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Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (v.66, #2)
Hydrogen bonding effects on infrared and Raman spectra of drug molecules by Laban Bondesson; Kurt V. Mikkelsen; Yi Luo; Per Garberg; Hans Ågren (pp. 213-224).
Infrared and Raman spectra of three drug molecules, aspirin, caffeine and ibuprofen, in gas phase and in aqueous solution have been simulated using hybrid density functional theory. The long range solvent effect is modelled by the polarizable continuum model, while the short range hydrogen bonding effects are taken care of by the super-molecular approach with explicit inclusion of water molecules. The calculated spectra are found to compare well with available experimental results. The agreement obtained make grounds for proposing theoretical modeling as a tool for characterizing changes in the bonding environments of drug molecules in terms of particular variations in their IR and Raman spectra.
Keywords: Drug molecules; Infrared; Raman; Solvent effect; Hydrogen bonding; DFT
Interaction of meso-tetrakis(4-sulphonatophenyl)porphine with chitosan in aqueous solutions by Alla Synytsya; Andriy Synytsya; Petra Blafkova; Karel Volka; Vladimír Král (pp. 225-235).
Interaction of meso-tetrakis(4-sulphonatophenyl)porphine (TPPS4) with chitosan ( Mr∼400kDa, N-acetyls ∼20mol.%) was studied in aqueous solutions. UV–vis absorption and circular dichroism (CD) spectroscopic titration of 10μmoll−1 TPPS4 with chitosan demonstrated that an addition of the polysaccharide at appropriate concentrations and pH values induce and support self-aggregation of the macrocycles. The mode of aggregation was strongly dependent on pH: stacking (H-type) aggregates predominated at weak acidic conditions (pH 4.8–6.8) and tilted (J-type) aggregates at pH 2.5. At the intermediate pH value (3.6) both types of TPPS4 aggregates were detected. High amount of chitosan (>0.05mmoll−1 of GlcN) disrupts H-aggregates forming monomeric porphyrin–chitosan complexes (pH 3.6–6.8), while J-aggregates (pH 2.5) are stable even at very high chitosan concentrations. CD titration experiments confirmed the formation of optically active species of TPPS4 in the presence of chitosan. The complex nature of CD bands assigned to both types of porphyrin aggregates indicated the occurrence of several chiral macrocyclic species dependently on pH value and chitosan concentration.
Keywords: TPPS; 4; Chitosan; Aggregation; UV–vis absorption; Circular dichroism
Photophysical properties of novel lanthanide (Tb3+, Dy3+, Eu3+) complexes with long chain para-carboxyphenol ester p-L-benzoate (L=dodecanoyloxy, myristoyloxy, palmitoyloxy and stearoyloxy) by Bing Xu; Bing Yan (pp. 236-242).
In this paper, a series of 12 binary luminescent lanthanide coordination compounds with long chain p-carboxyphenol ester were assembled. Both elemental analysis and infrared spectroscopy allowed to determine the complexes formula: LnL3, where Ln=Tb, Dy, Eu; L= p-dodecanoyloxybenzoate (12-OBA), p-myristoyloxybenzoate (14-OBA), p-palmitoyloxybenzoate (16-OBA) and p-stearoyloxybenzoate (18-OBA), respectively. The photophysical properties of these complexes were studied in detail with various of spectroscopies such as ultraviolet–visible absorption spectra, low temperature phosphorescence spectra and fluorescent spectra. The ultraviolet–visible absorption spectra showed that some bands shift with the different chain length of p-carboxyphenol ester. From the low temperature phosphorescent emission, the triplet state energies for these four ligands were determined to be around 24,242cm−1 (12-OBA), 24,612cm−1 (14-OBA), 24,084cm−1 (16-OBA) and 24,125cm−1 (18-OBA), respectively, suggesting they are suitable for the sensitization of the above lanthanide ions, especially for Tb3+ and Dy3+. The fluorescence excitation and emission spectra for these lanthanide complexes of the four ligands take agreement with the above predict from energy match.
Keywords: Lanthanide complexes; Long chain; p; -carboxyphenol ester; Photophysical property; Energy transfer; Spectroscopy
NMR spectrometric studies of complexation of [60]fullerene with series of meso-tetraphenylporphyrins by Sumanta Bhattacharya; Sandip K. Nayak; Subrata Chattopadhyay; Manas Banerjee (pp. 243-249).
Extensive1H NMR spectrometric studies have been done to gain information on the nature of molecular interactions of the supramolecular complexes of [60]fullerene with a series of meso-tetraphenylporphyrins, namely, meso-5,10,15,20-tetraphenylporphyrin (1), meso-5,10,15,20-tetra-2-bromophenyl-porphyrin (2) and meso-5,10,15,20-tetra-2-chlorophenyl-porphyrin (3) in toluene medium. [60]Fullerene has been shown to form 1:1 adducts with the above series of meso-tetraphenylporphyrins. Formation constants ( K) for all the complexes have been determined from the systematic variation of the NMR chemical shifts of beta proton of the porphyrin in presence of [60]fullerene. It has been observed that3 acts as a better donor in forming supramolecular complex with [60]fullerene.
Keywords: [60]Fullerene; meso; -Tetraphenylporphyrins; NMR study; Formation constant; Ab initio calculation
Structure and spectroscopic characteristics of 4- tert-butylphenoxyacetylhydrazones of arylaldehydes by S.N. Podyachev; I.A. Litvinov; R.R. Shagidullin; B.I. Buzykin; I. Bauer; D.V. Osyanina; L.V. Avvakumova; S.N. Sudakova; W.D. Habicher; A.I. Konovalov (pp. 250-261).
By reaction of 4- tert-butylphenoxyacetylhydrazide with aromatic aldehydes and acetone a new series of 4- tert-butylphenoxyacetylhydrazones was synthesized. The structural peculiarities of the investigated molecules have been determined by means of X-ray analysis and IR spectroscopy. The diagnostically important IR spectral criteria required for the conformational analysis of acethylhydrazones have been considered. It was established that the 4- tert-butylphenoxyacetylhydrazide in condensed phase exists only as aZN–C(O)-conformer. Its derivatives exist asEN–C(O) andZN–C(O)-forms. As a rule, the prevalence ofZN–C(O)-form has been observed in CCl4 solutions. The structure of investigated compounds is also determined by a system of inter- and intramolecular hydrogen bonds. The energy of hydrogen bonds was estimated.
Keywords: 4-; tert; -Butylphenoxyacetylhydrazide; 4-; tert; -Butylphenoxyacetylhydrazones; Conformation; Hydrogen bonds; IR spectroscopy; X-ray crystallography
Correlation of infrared spectra of zinc(II) carboxylates with their structures by V. Zeleňák; Z. Vargová; K. Györyová (pp. 262-272).
The correlation of the infrared spectra of zinc(II) carboxylates with their structures was investigated in the paper. The complexes with different modes of the carboxylate binding, from chelating, through bridging ( syn–syn, syn–anti, monatomic), ionic to monodentate were used for the study, namely [Zn(C6H5CHCHCOO)2(H2O)2] (I) with chelating carboxylate group (C6H5CHCHCOO=cinnamate), [Zn2(C6H5COO)4(pap)2] (II) with syn–syn bridging carboxylate (C6H5COO=benzoate; pap=papaverine), [Zn(C6H5CHCHCOO)2(mpcm)] n (III) with syn–anti carboxylate bridge (mpcm=methyl-3-pyridylcarbamate), [Zn(C5H4NCOO)2(H2O)4] (IV) with ionic carboxylate group (C5H4NCOO=nicotinate), [Zn(C6H5COO)2(pcb)2] n (V) with monodentate carboxylate coordination (pcb=3-pyridylcarbinol) and [Zn3(C6H5COO)6(nia)2] (VI) with syn–syn and monatomic carboxylate bridges (nia=nicotinamide). First, the mode of the carboxylate binding was assigned from the infrared spectra using the magnitude of the separation between the carboxylate stretches, Δexp= νas(COO−)− νs(COO−). Then the values Δexp were compared with those calculated from structural data of the carboxylate anion ( Δcalc). The conclusions about the carboxylate binding which resulted from the Δ values, were confronted with the crystal structure of the complexes. The limitations and recommendations were formulated to assign the mode of the carboxylate binding from the infrared spectra. The dependence of the Δexp values on the magnitudes of Zn–O–C angles in bidentate carboxylate coordination was observed.
Keywords: Zinc; Carboxylate; IR; Stretching vibration; Structure
Photoacoustic and luminescence spectra study on the effects of chlorine substituent on the energy transfer of Eu(III)–chlorobenzoic acid by Bin Hu; Da Chen; Qingde Su (pp. 273-277).
The photoacoustic (PA) amplitude spectra of three complexes of Eu(III) combined with chlorobenzoic acid (Eu( o-ClC6H4CO2)3·H2O, Eu( m-ClC6H4CO2)3·H2O and Eu( p-ClC6H4CO2)3·H2O) have been measured, and the PA phase of the different complexes have been calculated. Both the PA amplitude spectra and the luminescence spectra reflect the variation of the luminescent properties, and the PA phase is directly relative to the relaxation time. Since the relaxation is the process of the intramolecular energy transfer between the ligands and the central ion, the molecular structure of ligand is the important factor to decide the energy gap between the lowest triplet state of ligand and the resonance level of central ion. The effects of chlorine substituent on the molecular structure and energy gap of the complexes have been studied by PA phase and luminescence spectra.
Keywords: Photoacoustic phase; Chlorine substituent; Intramolecular energy transfer
Upconversion and fluorescence spectral studies of Er3+/Yb3+-codoped Bi2Q3–GeO2–Ga2Q3–Na2O glasses by Qiuhua Nie; Cheng Jiang; Xunsi Wang; Tiefeng Xu; Haoquan Li (pp. 278-281).
The absorption spectra and upconversion fluorescence spectra of Er3+/Yb3+-codoped natrium–gallium–germanium–bismuth glasses are measured and investigated. The intense green (533 and 549nm) and red (672nm) emission bands were simultaneously observed at room temperature. The quadratic dependence of the green and red emission on excitation power indicates that the two-photon absorption processes occur. The influence of Ga2C3 on upconversion intensity is investigated. The intensity of green emissions increases slowly with increasing Ga2O3 content, while the intensity of red emission increases significantly. The possible upconversion mechanisms for these glasses have also been discussed. The maximum phonon energy of the glasses determined based on the infrared (IR) spectral analysis is as low as 740cm−1. The studies indicate that Bi2O3–GeO2–Ga2O3–Na2O glasses may be potential materials for developing upconversion optical devices
Keywords: Rare-earth compounds; Optical materials; Frequency upconversion
A Fourier transform infrared spectroscopic study of Mg-rich, Mg-poor and acid leached palygorskites by Yuanfeng Cai; Jiyue Xue; D.A. Polya (pp. 282-288).
The FTIR spectra of pure magnesium-rich (Mg-rich) and magnesium-poor (Mg-poor) palygorskites, before and after short-term (<7h) and long-term (360h) acid leaching are presented here. Comparison of decomposition spectra of Mg-rich and Mg-poor palygorskites clearly shows that the absorption peaks related to pairs of octahedral cation differ depending on the octahedral site occupancy. Short-term acid leaching of palygorskites results in significant changes to FTIR absorption bands near 1200 and 790cm−1. As the acid attack progresses, the band at 1200cm−1 shifts to lower wavenumbers, whilst the band at 790cm−1, which here is assigned to SiU–O–SiD symmetrical stretching vibration, shifts to higher wavelengths. Longer-term leaching of palygorskites results in the disappearance of 900–1200cm−1 absorption bands, showing that the palygorskite has largely decomposed to amorphous silica. Assignments of several other bands have been made as follows: several vibrations relate to OH, i.e. 847cm−1, hygroscopic water (1635cm−1), Si–O vibrations 1100, 611–621, 470–481cm−1, etc. appear in the FTIR spectra of 360h acid leached palygorskite. Three bands near 1100, 611–621 and 470–481cm−1 relate to Si–O vibration of an ideal hexagonal (Si2O5)n sheet.
Keywords: FTIR spectroscopy; Palygorskite; Acid leaching; Hydroxyl stretching vibrations; XRF analysis
Synthesis, characterization and luminescence property of N, N′-di(pyridine N-oxide-2-yl)pyridine-2,6-dicarboxamide and corresponding lanthanide (III) complexes by Hai-Jun Zhang; Ru-Hu Gou; Lan Yan; Ru-Dong Yang (pp. 289-294).
A new ligand, N, N′-di(pyridine N-oxide-2-yl)pyridine-2,6-dicarboxamide (LH2) and its several lanthanide (III) complexes (La, Eu, Gd, Tb, Y) were synthesized and characterized in detail based on elemental analysis, conductivity measurements, IR,1H NMR, MS (FAB) and UV spectra and TG-DTA studies. The results indicated that the composition of these binary complexes is [Ln(LH2)(NO3)2·H2O]NO3· nH2O ( n=0–1); while the ligand has a good planar structure with strong hydrogen bonds. The fluorescence spectra exhibits that the Tb (III) complex and the Eu (III) complex display characteristic metal-centered fluorescence in solid state while ligand fluorescence is completely quenched. However, the Tb (III) complex displays more effective luminescence than the Eu (III) complex, which is attributed to especial effectivity in transferring energy from the lowest triplet energy level of the ligands ( T) onto the excited state (5D4) of Tb (III) than that (5D1) of Eu (III).
Keywords: Rare earth compounds; Fluorescence; Phosphorescence; Pyridine; N; -oxide; N; ,; N; ′-Di(pyridine; N; -oxide-2-yl)pyridine-2,6-dicarboxamide metal complexes
Selective and sensitized spectrophotometric determination of trace amounts of Ni(II) ion using α-benzyl dioxime in surfactant media by Mehrorang Ghaedi (pp. 295-301).
Highly sensitive and interference-free sensitized spectrophotometric method for the determination of Ni(II) ions is described. The method is based on the reaction between Ni(II) ion and benzyl dioxime in micellar media in the presence of sodium dodecyl sulfate (SDS). The absorbance is linear from 0.1 up to 25.0μgmL−1 in aqueous solution with repeatability (RSD) of 1.0% at a concentration of 1μgmL−1 and a detection limit of 0.12ngmL−1 and molar absorption coefficient of 68,600Lmol−1cm−1. The influence of reaction variables including type and amount of surfactant, pH, and amount of ligand and complexation time and the effect of interfering ions are investigated. The proposed procedure was applied to the determination of trace amounts of Ni(II) ion in tap water, river water, chocolate and vegetable without separation or organic solvent extraction.
Keywords: α-Benzyl dioxime (BDO); Spectrophotometric method; Surfactant media; Sodium dodecyl sulfate (SDS); Nickel(II) ion
Spectroscopic studies of the interaction between methylene blue–naphthol orange complex and anionic and cationic surfactants by Shunzo Yamamoto; Serina Kobashi; Ken-ichiro Tsutsui; Yoshimi Sueishi (pp. 302-306).
Initially, the absorbance of MB at 665nm decreased rapidly with increasing sodium dodecyl sulfate (SDS) concentration, but increased gradually above about 2.3×10−3M. However, the absorbance of MB was almost independent of the cetyltrimethylammonium bromide (CTAB) concentration. On the other hand, the absorbance of NpO was affected by addition of CTAB in a similar manner to the change in MB-SDS system, but not by addition of SDS. The absorption band of MB showed a small red-shift and a decrease in intensity upon addition of NpO, while that of NpO showed only the decrease in the intensity upon the addition of MB. These spectral changes were attributed to the formation of complexes between these dyes. The effects of anionic and cationic surfactants on the absorption spectra of mixtures of MB and NpO were also examined. Contrary to the effects on the absorption spectrum of MB and NpO, respectively, the absorbances of MB and NpO in the mixtures were changed with the additions of both anionic and cationic surfactants. The spectral changes were explained by changes in the forms of MB and NpO in the solutions with increasing surfactant concentrations.
Keywords: Methylene blue; α-Naphthol orange; Complex; Surfactants; Ion pair; Aggregation; Micelle
Spin-flop and spin-Peierls transition in doped CuGeO3 by O. Yalçın; F. Yıldız; B. Aktaş (pp. 307-311).
Ni++ ions doped inorganic CuGeO3 sample has been studied by using electron spin resonance (ESR) technique in the temperature range of 3–300K. The ESR spectrum of Cu++ ion has been observed to be strongly temperature dependent for inorganic spin-Peierls (SP) Cu0.96Ni0.04GeO3 samples. The ESR line width and ESR amplitude exponentially vanishes below a critical temperature, Tsp=14K. The one-dimensional (1D) antiferromagnetic (AF) spin chain formed of Cu++ is broken by Ni++ (spin-1) ion, giving uncoupled spins at the end of the chains that give extra contribution to the spectra at lower temperature and stabilizes a Néel state. The g-factor is much smaller than the expected value for isolated Cu++ and Ni++ ions and is much more anisotropic than for undoped samples [O. Yalçın, B. Aktaş, J. Magn. Magn. Mater. 258/259 (2003) 137 (reference therein)]. It is shown that the ground state of dimerized spins is singlet. The spin-flop (SF) phenomenon is obtained from AF state mixed condition and then ferromagnetic (FM) state. The spin-flop field slightly increases when increasing temperature in the temperature range 100–300K. The SF transition is showed almost AF order for Cu0.96Ni0.04GeO3.
Keywords: Spin-flop transition; Electron spin resonance; Spin-Peierls transition; CuGeO; 3PACS; 75.0.Jm; 76.30.Da; 71.20.Ps; 75.50.Ee; 75.10.Jm; 75.40.Cx
Electronic and vibrational spectra of Mn rich sursassite by B. Jagannadha Reddy; Ray L. Frost (pp. 312-317).
The optical spectrum of Mn2+ in octahedral coordination for sursassite is characterized by well resolved bands at 580, 515, 470, 390, 340, and 295nm (17240, 19420, 21280, 25640, 29410 and 33900cm−1). Crystal field parameters evaluated from the observed bands are Dq=690, B=680 and C=2800cm−1. A broad band centred around 13000cm−1 attributed to Fe(III) ion is an impurity in sursassite confirmed from EDX analysis. Vibrational spectra have been investigated both by IR and Raman spectroscopy. The correlation between vibrational modes and the structural properties of the manganese silicate, sursassite, is made and compared with other silicates. Two vibrational modes of CO32− observed; the antisymmetric stretching mode ( ν3) at 1420cm−1 (IR active) and the out-of-plane bending mode ( ν2) (IR and Raman active) at ∼875cm−1. This confirms the Mn rich phases in sursassite as observed from SEM probably an Mn carbonate-rhodochrosite.
Keywords: XRD and SEM analyses; UV–vis and NIR spectroscopy; Sursassite; Mn(II) distorted octahedral symmetry; Overtone and combination bands; Layered silicates; Infrared and Raman spectroscopy
Semiorganic nonlinear optical material for frequency doubling: Preparation and properties of sodium p-nitrophenolate dihydrate (SPNP) by S. Dhanuskodi; A. Pricilla Jeyakumari; S. Manivannan; J. Philip; S.K. Tiwari (pp. 318-322).
Sodium p-nitrophenolate (SPNP), a semiorganic nonlinear optical (NLO) material useful for frequency doubling in the IR region, has been synthesized. The solubility studies have been carried out in the temperature range 30–50°C. Single crystals (size 12mm×7mm×4mm) have been grown by slow evaporation of the saturated aqueous solution (methanol as solvent) at 30°C. The lattice parameters of the grown crystals have been determined by single crystal X-ray diffraction technique. The UV–vis–NIR transmittance spectrum has been recorded in the range 200–1500nm. The molecular structure was confirmed by FT-IR and FT-NMR. SPNP was thermally stable up to 103°C as determined by TG/DTA curves. By a modified Kurtz and Perry method, the powder SHG efficiency was found to be five times that of KDP and its phase matching property was established. Laser damage threshold of SPNP was determined using a Nd:YAG laser.
Keywords: PACS; 42.65.k; 42.70.Hj; 33.254.k; 61.66.HqSolubility; Solution growth; Single crystals; Nonlinear optical material
Optical characterization of Eu3+ and Tb3+ ions doped zinc lead borate glasses by A. Thulasiramudu; S. Buddhudu (pp. 323-328).
This paper reports on the spectral analysis of Eu3+ or Tb3+ ions (0.5mol%) doped heavy metal oxide (HMO) based zinc lead borate glasses from the measurement of their absorption, emission spectra and also different physical properties. From the XRD, DSC profiles, the glass nature and glass thermal properties have been studied. The measured emission spectrum of Eu3+ glass has revealed five transitions (5D0→7F0,7F1,7F2,7F3 and7F4) at 578, 591, 613, 654 and 702nm, respectively, with λexci=392nm (7F0→5L6). In the case of Tb3+:ZLB glass, four emission transitions such as (5D4→7F6,7F5,7F4 and7F3) that are located at 489, 542, 585 and 622nm, respectively, have been measured with λexci=374nm. For all these emission bands decay curves have been plotted to evaluate their lifetimes and the emission processes that arise in the glasses have been explained in terms of energy level schemes.
Keywords: Zinc lead borate glasses; Optical properties
Synthesis, characterization and DNA-binding studies of 2-carboxybenzaldehydeisonicotinoylhydrazone and its La(III), Sm(III) and Eu(III) complexes by Yuan Wang; Yan Wang; Zheng-Yin Yang (pp. 329-334).
2-Carboxybenzaldehydeisonicotinoylhydrazone (HL), and its three lanthanide complexes, LnL3·4H2O [Ln=La(1), Sm(2), Eu(3)], have been synthesized and characterized on the basis of elemental analyses, molar conductivities, IR spectra and thermal analyses. In addition, the DNA-binding properties of the ligand and its complexes have been investigated by absorption, fluorescence and viscosity measurements. The experimental results indicated that the complexes (2) and (3) can bind to DNA, but the ligand and the complex (1) cannot; the binding affinity of the complex (3) is higher than that of the complex (2) and the intrinsic binding constant Kb of the complex (3) is 7.86×104M−1.
Keywords: Synthesis; Lanthanide; Complexes; DNA-binding studies; 2-Carboxybenzaldehydeisonicotinoylhydrazone
Synthesis, crystal structure and characterization of photochromic 1,2-bis{2-ethyl-5-[2-(1,3-dioxolane)]-3-thienyl}perfluorocyclopentene by Shouzhi Pu; Tianshe Yang; Ruji Wang; Fushi Zhang; Jingkun Xu (pp. 335-340).
A novel photochromic diarylethene, 1,2-bis{2-ethyl-5-[2-(1,3-dioxolane)]-3-thienyl}perfluorocyclopentene (BEDTP), was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. Its photochromic and fluorescent properties were also investigated. The results showed that this compound exhibited reversible photochromism, changing from colorless to magenta after irradiation with UV light both in solution and in the crystalline phase. In hexane solution, the open-ring isomer of BEDTP exhibited relatively strong fluorescence at 400nm when excited at 282nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 254nm light and its closed-ring isomer showed almost no fluorescence.
Keywords: Diarylethene; Crystal structure; Photochromism; Fluorescence
Flow-injection chemiluminescence sensor for determination of isoniazid in urine sample based on molecularly imprinted polymer by Yan Xiong; Houjiang Zhou; Zhujun Zhang; Deyong He; Chao He (pp. 341-346).
In this paper, molecularly imprinted polymer (MIP) of isoniazid is synthesized through thermal radical copolymerization of metharylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of isoniazid template molecules. A novel flow injection chemiluminescence sensor for isoniazid determination is developed by packing the isoniazid-MIP into the flow cell as recognition elements. Isoniazid could be selectively adsorbed by the MIPs and the adsorbed isoniazid was sensed by its great enhancing effect on the weak CL reaction between luminol and periodate which were mixed in the flow cell. The enhanced CL intensity is linear in the range 2×10−9 to 2×10−7g/mL and the detection limit is 7×10−10g/mL (3 σ) isoniazid with a relative standard deviation 2.8% ( n=9) for 8×10−8g/mL. The sensor is reversible and reusable. It has a great improvement in sensitivity and selectivity for CL analysis. As a result, the sensor has been successfully applied to determination of isoniazid in human urine. At the same time, the binding characteristic of the polymer to isoniazid was evaluated by batch method and the dynamic method, respectively.
Keywords: Isoniazid; Molecularly imprinted polymer; Chemiluminescence sensor
Synthesis, spectral and oxidase studies of a new diamide copper(II) complex with pendant benzimidazolyl groups by Sunil K. Upadhyay; Sarita Tehlan; Pavan Mathur (pp. 347-352).
A new benzimidazole-based diamide ligand- N, N′-bis(alanine-2-benzimidazolyl) hexanediamide (ABHA) has been synthesized and utilized to prepare Cu(II) complexes of general composition [Cu(ABHA)X2]· nH2O,where X is an exogenous anionic ligand (X=Cl−,NO3−). Low temperature EPR spectra has been obtained that shows g∥> g⊥>2.0024, indicating a tetragonal geometry in the solution state. The complexes display a quasi-reversible redox wave due to the Cu(II)/Cu(I) reduction process. E1/2 values shift anodically as NO3−−, indicating that the bound NO3− stabilizes the Cu(II) ion while the bonded Cl− destabilizes it. The complex [Cu(ABHA)Cl2] has been found to oxidize dopamine to dopachrome or aminochrome, both in a methanolic and a reverse-miceller system. The oxidation of dopamine to aminochrome is reminiscent of the functioning of Prostglandin H-synthetase in brain cells which requires dopamine as a cofactor for catalytic activity.
Keywords: Copper(II) complexes; Dopamine; Aminochrome; Benzimidazole diamides
Spectral characterization and crystal structure of 2-benzoylpyridine nicotinoyl hydrazone by Mini Kuriakose; M.R. Prathapachandra Kurup; E. Suresh (pp. 353-358).
The synthesis, spectral characterization and crystal structure of 2-benzoylpyridine nicotinoyl hydrazone (HL) is reported. Spectral techniques employed include1H NMR, COSY homonuclear, HSQC heteronuclear correlation techniques, electronic and IR. The infrared spectrum suggests the existence of the compound in keto form in solid state, which is further established by the single crystal X-ray analysis. The compound crystallizes into a triclinic lattice with P-1 symmetry with two molecules per unit cell.
Keywords: Hydrazones; Nicotinic acid hydrazide; COSY; HSQC; Crystal structure
A simple and rapid flow injection chemiluminescence determination of cysteine with Ru(phen)32+–Ce(IV) system by B. Rezaei; A. Mokhtari (pp. 359-363).
A new chemiluminescence system was developed for the determination of cysteine by flow injection system. This method is based on the reaction of L-cysteine with Ru(phen)32+ and Ce(IV) to produce chemiluminescence. The calibration curve was linear over the range 8.0×10−7 to 4.0×10−5 and 4.0×10−5 to 1.0×10−3M with a detection limit of 7.0×10−7M (S/N=3). The relative standard deviation of 4.0×10−6M cysteine was found 3.5% ( n=10). The influence of potential interfering substances was studied. The proposed method was successfully applied for the flow injection determination of cysteine in the real samples with minimum sampling rate of 90sample/h.
Keywords: Cysteine; Flow injection; Ruthenium; Chemiluminescence
Synthesis and characterization of thiolate–Ag(I) complexes by solid-state and solution NMR and their antimicrobial activity by Anvarhusein A. Isab; Mohammed I.M. Wazeer (pp. 364-370).
Silver(I) complexes of several thiolates have been prepared. These complexes have been characterized by elemental analysis and13C NMR spectroscopy. All the Ag(I)–thiolate complexes are polymeric in nature. Therefore,13C CP MAS NMR is being used extensively to analyze the binding site of the ligand and the nature of complexation. A significant shift difference was observed for S binding site whereas smaller shift was observed for carboxylate binding site. The antimicrobial activities for Ag(I)–glutathione complex was measured and compared with Ag(I)–captopril complex.
Keywords: Thiolates; Silver(I) complexes; CP MAS NMR; Antimicrobial activity
One color resonant two photon ionization spectroscopy of p-methylstyrene and theoretical calculation by Jiangou Huang; Daoqing Xiao; Weibin Bi; Xiling Xu; Zhen Gao; Qihe Zhu; Cunhao Zhang (pp. 371-376).
The band origin of the S1←S0 transition of p-methylstyrene is determined to be 34,276cm−1 by one color resonant two photon ionization (1C-R2PI) method, which is red shifted by 3811cm−1 with respect to that of benzene. This indicates that the interaction of the methyl and vinyl groups with the ring in the S1 state is greater than that in the S0 state. The active vibrations assigned from the R2PI spectrum are found to be the in-plane ring modes. The bands at 399, 613, 724, and 786cm−1 are assigned to the vibrations 9b, 6b, 12, and 1, respectively, and discussed in detail. The experimental results are well supported by ab initio and density functional theory (DFT) calculations.
Keywords: p; -Methylstyrene; One color resonant two-photon ionization (1C-R2PI); Vibrational spectrum; Ab initio; Density functional theory (DFT)
Luminescent properties of solvent effect for europium and terbium nitrate complexes with 3,3,7,7-tetra[ N-benzyl- N-phenyl(acetamide)-2-oxymethyl]-5-oxanonane by Ke-Wei Lei; Wei-Sheng Liu; Min-Yu Tan (pp. 377-380).
The multipodal ligand 3,3,7,7-tetra[ N-benzyl- N-phenyl(acetamide)-2-oxymethyl]-5-oxanonane (L) and its europium and terbium nitrate complexes were synthesized. The complexes were characterized by elemental analysis, IR, fluorescence spectroscopy and conductivity. The lanthanide atoms are coordinated by 0 atoms from CO, COC. With the difference of the solvent, the fluorescence properties of solvent effect for the complexes were investigated. Some factors that influencing the fluorescent intensity were discussed.
Keywords: Ether–amide type multipodal ligand; Lanthanide; Fluorescence; Solvent effect
Vibrational spectra and assignments of 5-amino-2-chlorobenzoic acid by ab initio Hartree–Fock and density functional methods by N. Sundaraganesan; B. Dominic Joshua; K. Settu (pp. 381-388).
The Fourier transform Raman and Fourier transform infrared spectra of 5-amino-2-chlorobenzoic acid (5A2CBA) were recorded in the solid phase. Geometry opitimizations were done without any constraint and harmonic-vibrational wavenumber and several thermodynamic parameters were calculated for the minimum energy conformer at ab initio and DFT levels invoking 6-311G(d,p) basis set and the results are compared with the experimental values with the help of three specific scaling procedures, the observed vibrational wavenumbers in FTIR and FT-Raman spectra were analyzed and assigned to different normal modes of the molecule. Most of the modes have wavenumbers in the expected range, the error obtained was in general very low. The appropriate theoretical spectrograms for the FTIR spectra of the title molecule were also constructed.
Keywords: FTIR and FT-Raman spectra: Ab initio and DFT; 5-Amino-2-chlorobenzoic acid; Vibrational analysis
Effect of B2O3 on luminescence of erbium doped tellurite glasses by Xiang Shen; Qiuhua Nie; Tiefeng Xu; Shixun Dai; Xunsi Wang (pp. 389-393).
The B2O3 was introduced into the Er3+ doped TeO2–ZnO–Na2O glass to increase the phonon energy of the host. The effect of B2O3 on the non-radiative rate of the4I11/2→4I13/2 transition of Er3+, the lifetime of the4I11/2 and4I13/2 levels, the green and red upconversion emissions intensity, and the4I13/2→4I15/2 emission intensity was discussed. The results show that the phonon energy of boro-tellurite glass is close to that of germanate glass and is quite smaller than that of borate glass. The lifetime of4I11/2 level and the upconversion emissions decrease with increasing B2O3 concentration. The higher OH group concentration presented in the boro-tellurite glass may shorten the lifetime of4I13/2 level and also reduce the quantum efficiency of4I13/2→4I15/2 emission. The future dehydrating procedures are suggested to enhance the efficiency of amplification at 1.5μm band.
Keywords: Tellurite glass; Erbium; Phonon energy; Upconversion; Optical amplifier
Vibrational assignment and structure of dibenzoylmethane by S.F. Tayyari; H. Rahemi; A.R. Nekoei; M. Zahedi-Tabrizi; Y.A. Wang (pp. 394-404).
Molecular structure and vibrational frequencies of 1,3-diphenyl-1,3-propanedione, known as dibenzoylmethane (DBM), have been investigated by means of density functional theory (DFT) calculations. The results were compared with those of benzoylacetone (BA) and acetylacetone (AA), the parent molecule. IR and Raman spectra of DBM and its deuterated analogue were clearly assigned.The calculated hydrogen bond energy of DBM is 16.15kcal/mol, calculated at B3LYP/6-311++G** level of theory, which is 0.28kcal/mol more than that of AA. This result is in agreement with the vibrational and NMR spectroscopy results. The molecular stability and the hydrogen bond strength were investigated by applying the Natural Bond Orbital analysis (NBO) and geometry calculations. The theoretical calculations indicate that the hydrogen bond in DBM is relatively stronger than that in BA and AA.
Keywords: Vibrational assignment; Dibenzoylmethane; Intramolecular hydrogen bond; β-Diketone; NBO
Ab initio and density functional computations of the vibrational spectrum, molecular geometry and some molecular properties of the antidepressant drug sertraline (Zoloft) hydrochloride by Seda Sagdinc; Fatma Kandemirli; Sevgi Haman Bayari (pp. 405-412).
Sertraline hydrochloride is a highly potent and selective inhibitor of serotonin (5HT). It is a basic compound of pharmaceutical application for antidepressant treatment (brand name: Zoloft). Ab initio and density functional computations of the vibrational (IR) spectrum, the molecular geometry, the atomic charges and polarizabilities were carried out. The infrared spectrum of sertraline is recorded in the solid state. The observed IR wave numbers were analysed in light of the computed vibrational spectrum. On the basis of the comparison between calculated and experimental results and the comparison with related molecules, assignments of fundamental vibrational modes are examined. The X-ray geometry and experimental frequencies are compared with the results of our theoretical calculations.
Keywords: DFT and HF calculations; Sertraline hydrochloride; IR spectra
Vibrational behavior of the phosphates ions in dittmarite-type compounds M′M″PO4·H2O (M′=K+, NH4+; M″=Mn2+, Co2+, Ni2+) by Violeta G. Koleva (pp. 413-418).
The IR and Raman spectra of the isostructural M′M″PO4·H2O compounds (M′=K+, NH4+; M″=Mn2+, Co2+, Ni2+) are reported and discussed with respect to the normal vibrations of the PO43− ions. The vibrational behavior of PO43− is in agreement with its low site symmetry Cs in the lattices—the symmetric ν1 and ν2 modes are activated in the IR spectra and the degeneration of the asymmetric ν3 and ν4 modes is lifted. A relatively large unit-cell group splitting is observed for ν1 in both the IR and Raman spectra and for ν3 in Raman spectra. It has been established that the mean wavenumbers of the PO stretches (ν¯PO) are not affected by the M2+ ions present, but they are lower for the NH4-series than for the K-one (predominant influence of both the smaller repulsion potential and the hydrogen bonds in the NH4-lattices over the influence of the M+–O interactions). The extent of the energetic distortion of the PO43− ions has been estimated based on the spectroscopic data for the site group splitting of the asymmetric modes (Δ ν3 and Δ ν4), the separation between the highest and the lowest wavenumbered PO stretches (Δ νmax) and the intensity of ν1 in the IR spectra. The data provide an evidence that the PO43− ions in KM″PO4·H2O are more distorted regarding the PO bond lengths than those in NH4M″PO4·H2O, but their angular distortion is the same in both series. The trends for the energetic distortion of the phosphate ions found from the spectroscopic data correspond to the data for their geometric distortion deduced from the values of the distortion indices DI(PO) and DI(OPO).
Keywords: Infrared and Raman spectra; Ammonium metal(II) phosphate monohydrates; Potassium metal(II) phosphate monohydrates; Normal PO; 4; 3−; vibrations; Distortion of the PO; 4; 3−; ions
Anharmonicity of water stretching vibrations in series of isomorphous crystalline hydrates by Ljupčo Pejov; Gligor Jovanovski; Orhideja Grupče; Bojan Šoptrajanov (pp. 419-426).
On the basis of the experimentally obtained frequencies of isotopically isolated OH and OD species, the anharmonicity constants, as well as the harmonic eigenvalues of the OH and OD stretching vibrations for two members of the isomorphous series of metal(II) saccharinates hexahydrates (those of Mn and Cu) were calculated using several theoretical models [B. Berglund, J. Lindgren, J. Tegenfeldt, J. Mol. Struct. 43 (1978) 169, M.G. Sceats, S.A. Rice, J. Chem. Phys. 71 (1979) 973, H. Engstrom, J.B. Bates, L.A. Boatner, J. Chem. Phys. 73 (1980) 1073]. The anharmonicity constants and the ν(OH)/ ν(OD) isotopic ratios correlate well with the stretching frequencies of the isotopically isolated OH and OD oscillators. Both anharmonicity constants and isotopic ratios as criteria for the anharmonicity of the OH (OD) vibrations show that, with a very few exceptions, it increases with the increase in the hydrogen bond strength. The exceptions from the trend are explained in terms of local electrostatic field differences and force constant changes due to the coordination to the metal ion. The obtained regression equations were used to predict the anharmonicity constants of the ν(OD) modes in other members of the series. Within the three-particle model of the hydrogen bonded complex, the parameters characterising the coupling of the ν(OH)/ ν(OD)/modes with the low-frequency ν(O⋯O) ones were estimated. The positions of the overtones of OH and OD stretching vibrations in the compounds of copper and manganese were estimated using the calculated anharmonicity parameters. The predicted values for the OD oscillators were compared with the experimentally obtained data. Model calculations of the described type are shown to be valuable in the assignment of the second-order transitions, especially in complex systems.
Keywords: Anharmonicity constants; Hydrogen bonding; Crystalline hydrates; Isomorphous compounds; Isotopic ratio; Non-linear regression; Overtone and combination modes
Luminescent property and catalytic activity of Ru(II) carbonyl complexes containing N, O donor of 2-hydroxy-1-naphthylideneimines by M. Sivagamasundari; R. Ramesh (pp. 427-433).
The reaction of the chelating ligands (obtained by the condensation of 2-hydroxy-1-naphthaldehyde with various primary amines) with [RuHCl(CO)(EPh3)2(B)] (where E=P; B=PPh3, py or pip: E=As; B=AsPh3) in benzene afforded new stable ruthenium(II) carbonyl complexes of the general formula [Ru(Cl)(CO)(EPh3)(B)(L)] (L=anion of bidentate Schiff bases). The structure of the new complexes was investigated using elemental analyses, spectral (FT–IR, UV–vis and1H NMR) and electrochemical studies and is found to be octahedral. All the metal complexes exhibit characteristic MLCT absorption and luminescence bands in the visible region. The luminescence efficiency of the ruthenium(II) complexes was explained based on the ligand environment around the metal ion. These complexes catalyze oxidation of primary and secondary alcohols into their corresponding carbonyl compounds in the presence of N-methylmorpholine- N-oxide (NMO) as the source of oxygen. The formation of high valent RuIV=O species as a catalytic intermediate is proposed for the catalytic process.
Keywords: Ru(II) carbonyl complexes; Synthesis; Characterization; Luminescence; Oxidation
Spectrophotometric determination of trace copper in water samples with thiomichlersketone by Dayou Fu; Dong Yuan (pp. 434-437).
A simple and sensitive spectrophotometric method for determination of trace copper in water samples is proposed. In the presence of pH 4.6 HAc–NaAc buffer solution and surfactant polyethylene octyl phenyl ether (OP) medium, copper reacts with thiomichlersketone (TMK) to form a stable 1:4 complex. The complex Cu(II)–TMK–OP shows maximum absorbance at 500nm with a molar absorptivity value of 5.7×104lmol−1cm−1. Beer's law is obeyed for copper concentrations in the range of 0–15μg/25ml. The average recovery of copper is between 95.8 and 106%. The method has been applied for determination of trace copper in different water samples with satisfactory results.
Keywords: Copper; Thiomichlersketone; Spectrophotometric
A theoretical study on N-phenyl- N′-(2-thienylmethylene)hydrazine by F. Yakuphanoglu; Y. Atalay; M. Sekerci (pp. 438-441).
The molecular geometry and vibrational frequencies of N-phenyl- N′-(2-thienylmethylene)hydrazine (C11H10N2S) have been calculated using Hartree–Fock and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and angles obtained using HF and DFT (B3LYP) are in agreement with the experimental data. B3LYP method seems to be appropriate than HF method for the calculation of vibrational frequencies and geometrical parameters of the (C11H10N2S) compound.
Keywords: N; -Phenyl-; N; ′-(2-thienylmethylene)hydrazine (C; 11; H; 10; N; 2; S); IR spectra; DFT; HF
Spectroscopic study on the zinc-contaminated soils for the determination of zinc speciation by Tzu-Hsing Ko; Meng-Hsiu Shih; Hsin-Ta Hsueh (pp. 442-447).
The purpose of this paper reported the zinc species in the highly contaminated soils from metallurgical area around Erh-Jen River in the southern of Taiwan. FTIR and XPS were used to investigate the zinc species in the contaminated soils. Through a FTIR analysis, appreciable of zinc bound by organic matter was found and their bonding structure consisted of antisymmetric and symmetric stretchings, Zn–HSsym and Zn–HSasym. With XPS analysis, the Angstrom scale depth scan was surveyed for investigation the zinc speciation. No signal of zinc was detected in the depth of 900Å for the larger particle contaminated soils whereas the detectable signal of zinc was determined in the XPS experiment. With further regression and fitting results, the major zinc species presented in the surface of larger and fine particle contaminated soils consisted of reductive and oxidative zinc species. In the deeper depth of contaminated soils, an inverse spinel zinc ferrite was found in the case of larger particle soil. No inverse spinel zinc ferrite was detected in the case of fine particle soil and could be attributed to the relatively small particle size.
Keywords: Zinc species; Contaminated soils; Angstrom scale; Spinel; Zinc ferrite
Fluorescence quenching of water-soluble conjugated polymer by metal cations and its application in sensor by Yan-Guo Chen; Dan Zhao; Zhi-Ke He; Xin-Ping Ai (pp. 448-452).
The effects of different metal cations on the fluorescence of water-soluble conjugated polymer (CP) and their quenching mechanism have been explored. Most transition metal cations, especially noble metal cations, such as Pd2+, Ru3+, and Pt2+ possessed higher quenching efficiency to CP fluorescence than that of the main group metal cations and other transition metal cations, which have filled or half-full outmost electron layer configurations. Base on this, rapid, sensitive detection of noble metal cations can be realized and a novel quencher-tether-ligand (QTL) probe was developed to detect avidin and streptavidin.
Keywords: Conjugated polymer; Metal cations; Fluorescence quenching; QTL
ESR and optical study of Mn2+ doped ammonium selenate single crystals by Ram Kripal; Ashutosh Kumar Shukla (pp. 453-456).
ESR and optical absorption studies of manganese doped ammonium selenate single crystals are performed at X-band and room temperature to ascertain the site symmetry and location of impurity ions in the lattice. Manganese ions are expected to enter the lattice interstitially. Various spin Hamiltonian parameters are determined. Optical absorption study is also done and associated distortion in the crystal lattice is estimated.
Keywords: PACS; 76.30Spin Hamiltonian; Optical absorption; Crystal field; Distortion
A water-soluble fluorescent fluoride ion probe based on Alizarin Red S–Al(III) complex by R. Sai Sathish; M. Ravi Kumar; G. Nageswara Rao; K. Anil Kumar; C. Janardhana (pp. 457-461).
A new water-soluble fluorescent fluoride ion signaling system has been developed based on the ligand exchange mechanism in aqueous medium. This procedure is based on the exchange of two Alizarin Red S (ARS) molecules coordinated to Al(III) by fluoride ion without interference from other common anions. The binary complex of ARS with Al(III) provides a sensitive signaling system for fluoride ion in the concentration range from 5×10−6 to 3×10−4M. The ligand exchange reaction of ARS–Al(III) complex with fluoride ion has been investigated by UV–vis and fluorescence spectroscopies combined with the AM1 semi-empirical quantum chemical calculations. The pale orange fluorescence ( λmax=575nm) exhibited by the complex upon excitation at 435nm decreases in intensity with fluoride addition with a detection limit of 0.1mgL−1.
Keywords: Alizarin Red S; AlCl; 3; Ligand exchange; Fluoride sensing; AM1
Theoretical investigations of the specific heat functions for the orthorhombic Nd+3 centers in some crystals by Fuat Bayrakçeken; Oktay J. Demir; İpek Ş. Karaaslan (pp. 462-466).
Garnets doped with Nd+3 have attracted extensive interests because of their applications in solid-state lasers, as well as upconversion luminescence and magneto-optical and magnetic properties. Usually, these properties are closely related to the local structures and properties of the Nd+3 impurities in the hosts. Since information about electronic states and local structures of the impurity Nd+3 in the garnets would be helpful to the understanding of the properties of these materials, theoretical investigations on the specific heat functions and the local structures for these Nd+3 centers are of significance.
Keywords: Nd; 3+; doped garnets; Crystals; Laser optical materials; Specific heat functions; Nd; 3+
Comparative study of the hydrogen-bonded complexes of phenol and o-cyanophenol with CO by Yordanka Dimitrova; Lalka I. Daskalova (pp. 467-473).
The structures, stability and vibrational spectra of the hydrogen-bonded complexes of carbon monoxide (CO) with phenol and o-cyanophenol ( syn and anti) have been studied using ab initio and DFT calculations. Full geometry optimization has been performed for the studied complexes by DFT (BLYP/6-311++G(d,p)) calculations. The calculations show that the hydrogen-bond formation of carbon monoxide (CO) with phenol and o-cyanophenol ( syn and anti) leads to the following stable structures: C6H5OH…CO (1A); C6H5OH…OC (1B); (syn) o-CNC6H4OH…CO (2A-syn); (syn) o-CNC6H4OH…OC (2B-syn); (anti) o-CNC6H4OH…CO (2A-anti) and (anti) o-CNC6H4OH…OC (2B-anti). Having in mind the corrected values of the dissociation energy, the studied hydrogen-bonded complexes can be ordered according their stability as follows:2A-anti>2A-syn>1A>2B-anti>1B>2B-syn. The predicted red-shifts for the νOH vibration with the B3LYP/6-311++G(d,p) calculations for the structures1A (−46cm−1),2A-syn (−60cm−1) and2A-anti (−73cm−1) are in very good agreement with the experimentally observed. The magnitudes of the wavenumber shifts are indicative of relatively weak OH…C hydrogen-bonded interactions. The calculations predict an increase of the IR intensity of the νOH vibration in the complexes1A,2A-anti and2A-syn up to five times.
Keywords: Hydrogen-bonded CO complexes; Ab initio; DFT calculations
Surface-enhanced vibrational spectra of 2-nitrofluorene by E.A. Carrasco-Flores; M.M. Campos-Vallette; R.E. Clavijo (pp. 474-479).
The infrared and Raman spectra of the isolated adsorbate 2-nitrofluorene (2NF) have been registered and the spectral assignment was performed on the basis of both previous data concerning related molecules and density functional theory DFT calculations. The theoretical calculations were compared to the experimental results, obtaining a good agreement with the IR and Raman data. The surface-enhanced infrared and Raman spectra, SEIRA and SERS, of 2NF on different metal surfaces were registered; the best spectra were obtained by using the 633nm laser line. The most probable orientation and organization of the adsorbate on the surface were inferred from the reflection–absorption infrared spectrum RAIRS and SERS and SEIRA data.
Keywords: Vibrational spectroscopy; Raman; SERS; 2-Nitrofluorene
Spectroscopic studies of some thiosemicarbazide compounds derived from Girard's T and P by M.M. Mostafa (pp. 480-486).
Three new derivatives of thiosemicarbazides, derived from the reactions of ethyl-, allyl- and phenyl isothiocyanates with Girard's T [(carboxymethyl) trimethylammonium chloride hydrazide] and P [1-(carboxymethyl) pyridinium chloride hydrazide], have been isolated and characterized by chemical analyses, conductivities, spectral (IR,1H NMR) and molecular weight measurements. The most important assignments of the functional groups in the isolated solid organic compounds have been determined using IR spectra. Also, the main functional groups in the skeleton of these compounds have been characterized using1H NMR spectra. Moreover, a comparative studies between the three thiosemicarbazide derivatives have been carried out. The role of the existence of ethyl-, allyl-, phenyl-, [(CH3)3N+–] and [C5H5N+–] on the position of the functional groups has been investigated. Finally, the absence of any type of hydrogen bonding (inter- and/or intra-) within these compounds is discussed on the basis of the data of melting points, IR and1H NMR spectra and molecular weight measurements.
Keywords: Spectroscopic studies; Thiosemicarbazide derivatives; Girard's T and P derivatives
Temperature and pressure dependence of the mode Grüneisen parameters close to the melting point in hexagonal ice by H. Karacali; H. Yurtseven (pp. 487-492).
We reexamine the Pippard relations in this study by relating the specific heat C P to the Raman frequency shifts1ν∂ν∂TP and the thermal expansivity αp to the1ν∂ν∂PT, when the mode Grüneisen parameter depends on the temperature and pressure close to the melting point in hexagonal ice. From linear relations between them, the values of the slopedPdT are deduced in this crystal.Our slope values calculated here do not change significantly compared to those obtained when the mode Grüneisen parameter is taken as a constant close to the melting point in hexagonal ice.
Keywords: Mode Grüneisen parameters; Hexagonal ice; Melting point
Determination of trace lead by solid substrate room temperature phosphorescence enhancing method based on heavy atom effect and dissoluble manganese supramolecule containing rhodamine 6G luminescent particles by Lin Xuan; Wu Ruo-Hong; Li Xiao-Ju; Chen Li; Lin Qing-Wei; GAO Wen-Yan; Zheng Ai-Fang; Liu Jia-Ming; Zhu Guo-Hui; Huang Xiao-Mei (pp. 493-498).
Dissoluble manganese supramolecule containing rhodamine 6G luminescent particles (M2) are synthesized, based on dissoluble manganese supramolecule (M1) doping rhodamine 6G (R.6G), by crystalline method. The particle diameters of M1 and M2 determined by ETM are both of micron degree. M1 and M2 can emit solid substrate room temperature phosphorescence (SS-RTP) on filter paper. The transition probability from the singlet state (S1) to triplet state (T1) of the luminescent molecules was greatly enhanced, based on the increment of luminescent molecules for each spot and the heavy atom effect of certain amount of Pb2+. As a result, the phosphorescence intensity ( Ip) of M2 was increased sharply, and the enhancing value of phosphorescence intensity (Δ Ip) is directly proportional to the concentration of Pb2+. Thus, a new method of SS-RTP enhancing for the determination of trace lead is established based on manganese supramolecule containing rhodamine 6G luminescent particles. The linear range of this method is 0.0040–0.400pgspot−1 of Pb2+ (corresponding concentration, 0.01–1.0ngmL−1; sample volume, 0.4μLspot−1), with a detection limit (LD) of 0.0011pgspot−1 (corresponding concentration, 2.8×10−12gmL−1 of Pb2+, n=11). For the working solutions containing 0.0040 and 0.40ngmL−1 of Pb2+, they were determined repeatedly for seven times, respectively. The R.S.D.s were 3.2 and 3.8%, respectively. This method has good repeatability, sensitivity and high precision. It has been applied to the determination of trace lead in human hair and tea samples with satisfactory results.
Keywords: Lead; Solid substrate room temperature phosphorescence enhancing method; Manganese supramolecule; Rhodamine 6G luminescent particles; Heavy atom effect
Kinetic spectrophotometric method for o-phenylenediamine in the presence of gold(III) by Özlen Altun; Halide Akbaş; Emre Dölen (pp. 499-502).
From the color developing reactions of o-phenylenediamine oxidizing agent and gold(III), the kinetic reactions between both of them in aquaeous solutions were studied using spectrophotometric and differential method. Light absorbances in the visible spectral range are measured as a function of mole fractions of phenylenediamine at a fixed gold(III) concentration and as a function of mole fraction of gold(III) at a fixed o-phenylenediamine concentration at periodic time internal. In the differential method, which was suggested by van’t Hoff, one deals with the actual rates of reactions as determined by measuring the slopes of absorbance–time curves. Optimum condition of the reaction were established as pH 6 at λ=466 nm and room temperature. When the oxidation of o-phenylenediamine by gold(III) was investigated, it was observed that the following rate formula and rate constant were found:v=k[Au+3]1/2[o-phenylenediamine]1/2,k=2.33×10−2s−1
Keywords: Spectrophotometry; Differential method; Gold(III); o; -Phenylenediamine; Reaction kinetics
Vibrational spectra and structure of 5,6-diamino uracil and 5,6-dihydro-5-methyl uracil by density functional theory calculations by V. Krishnakumar; R. Ramasamy (pp. 503-511).
The molecular vibrations of 5,6-diamino uracil and 5,6-dihydro-5-methyl uracil were investigated in polycrystalline sample, at room temperature, by FT-IR and FT-Raman spectroscopies. The spectra were interpreted with the aid of normal coordinate analysis following a full structure optimization and force field calculations based on the density functional theory (DFT) using standard B3LYP/6-31G* and B3LYP/6-311+G** methods and basis set combinations. The DFT force field transformed to natural internal coordinates was corrected by a well-established set of scale factors that were found to be transferable to the title compounds. The infrared and Raman spectra were also predicted from the calculated intensities. Comparison of the simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.
Keywords: Vibrational spectra; DFT calculations; SQM force field; Vibrational assignment; 5,6-Diamino uracil; 5,6-Dihydro-5-methyl uracil
Jahn-Teller distortion geometries and electronic structures of Ga3Ge, GaGe3, and their ions by Xiaolei Zhu (pp. 512-520).
Computational studies on the geometric, electronic, and spectroscopic properties of electronic states are presented for GaGe3, Ga3Ge, and their ions using the CASSCF and DFT(B3LYP)/CCSD(T)/QCISD(T) techniques. The optimized geometries of electronic states, vibrational frequencies, energy separations, Mulliken populations, ionization energies, electron affinities, binding energies are obtained. The anion photoelectron spectra of GaGe3− and Ga3Ge− are predicted. In addition, the results from the low-lying states of GaGe3 and Ga3Ge are compared with those of GaSi3 and Ga3Si. Results demonstrate that the equilibrium geometries of most electronic states of GaGe3, Ga3Ge, and their ions exhibit Jahn-Teller distortion. It is interesting to find that there is not charge transfer between Ga and Ge atoms upon an electron attachment to the ground states of GaGe3 and Ga3Ge, while the amount of charge transfer between Ga and Ge atoms significantly increases upon an electron ionization from the ground state of Ga3Ge.
Keywords: Electronic state; Ga; 3; Ge; GaGe; 3; Cluster; Jahn-Teller distortion