Inorganic Chemistry Communications (v.6, #9)

Contents list (iii-iv).

In situ 27Al NMR experiments under hydrothermal and room temperature conditions demonstrate that aluminum monomers are the species controlling the Al13 Keggin ε conversion into Al30. New 27Al NMR signatures of Keggin-type aluminum polycation are observed in solution. A chemical pathway is proposed to explain the isomerization process.
Keywords: Al13; Al30; Aluminum polycations; 27Al NMR; Isomerization;

The hydrothermal reaction of H2aip (aip2−=5-aminoisophthalate) and Cd(II) acetate dihydrate yields an unprecedented three-dimensional (3,4)-connected network, [Cd(aip)(H2O)] · H2O, with 658 topology and interesting photoluminescent behaviour in the solid state.
Keywords: 658 Topology; 5-Aminoisophthalate; Cadmium(II); Crystal structure;

Oxidative addition of halogens to MoRu(CO)6(dppm)2 by Mozhgan Khorasani-Motlagh; Nasser Safari; Craig B Pamplin; Brian O Patrick; Brian R James (1175-1179).
Halogens oxidatively add to MoRu(CO)6(μ-dppm)2 (1) at ambient temperature to yield [(CO)2Mo(μ-X)(μ-CO)(μ-dppm)2Ru(CO)2]+[Mo(CO)4X3], where X=Cl (2) or I (3), dppm=Ph2PCH2PPh2, and the μ-CO is semi-bridging. Complexes 2 and 3 have been characterized by elemental analysis, conductivity, and NMR spectroscopy, while the molecular structure of 3 has been determined by X-ray crystallography. Ignoring a weak metal–metal bond interaction, the cation of 3 is most easily described as pseudo-octahedral at Ru(II) and Mo(0) centres; the anion is a monocapped octahedron that has been described previously.
Keywords: Molybdenum complex; Ruthenium complex; Bis(diphenylphosphino)methane; Halogen reactivity; Crystal structure; Semi-bridged carbonyl;

The structure of the cis-equatorial isomer of [Cr(ed3a)(H2O)] · H2O (ed3a=ethylenediamine-N,N,N -triacetate ion) was determined by X-ray diffraction method. The complex crystallizes in the monoclinic space group P21/n, a=7.004(1) Å, b=15.958(2) Å, c=11.046(1) Å, β=97.16(1)°, and Z=4. Conformational analysis of the three possible geometrical isomers, trans(H2O,N), trans(H2O,N H ), and trans(H2O,O) of [Cr(ed3a)(H2O)] moiety, performed using the consistent force field (CFF) program with the recently developed parameters for EDTA-type complexes, yielded structural details and energies of the minimized form for each of the isomers. Calculated energies showed that the cis-eq isomer is the most stable one, with the geometry in a very good agreement with the crystallographic structure. Comparison of the molecular mechanics calculations with those for the analogous [Cr(ed3p)(H2O)] · H2O (ed3p=ethylenediamine-N,N,N -tripropionate ion) revealed some general patterns for the conformational preference of EDTA-type complexes.
Keywords: Cr(III) complexes; Multidentate chelates; X-ray crystal structure; Molecular mechanics (MM);

Synthesis and crystal structure of [Mg3Cl5(Et2O)6]+[Me2SbI2] by Wu Zhang; Ji-Ping Hu; Xiao-Feng Ding; Yun-Jun Wu; Zhong-Wen Ye (1185-1187).
The title complex [Mg3Cl5(Et2O)6]+[Me2SbI2] has been prepared by the reaction of Grignard reagent MeMgI with antimony trichloride in diethyl ether and its crystal structure was characterized by X-ray diffraction. It crystallizes in the monoclinic space group C2/c, with a=18.1507(13),b=20.1850(13),c=14.0547(10) Å, β=110.390(2)°, V=4826.6(6) Å3, Z=4,D c=1.514 g cm−3, F(000)=2192, Mo-Kα radiation (λ=0.071073 nm). The final R and ωR are 0.0587 and 0.1728, respectively, with 4716 observed reflections. It is an halogen exchange product, explanation for probable process was given.
Keywords: Crystal structure; Grignard reagent; Antimony complex;

Structure and magnetic properties of a one-dimensional chain complex {[Mn2(TPA)2(o-phth)](ClO4)2}n by Lei Yang; Fang Bian; Shi-ping Yan; Dai-zheng Liao; Peng Cheng; Zong-hui Jiang (1188-1191).
A terephthalate-bridged chain complex of {[Mn2(TPA)2(o-phth)](ClO4)2}n (TPA=tris(2-pyridylmethyl)amine, o-phth=terephthalato dianion) was synthesized and characterized by X-ray crystallography and magnetic measurements. In the compound, each terephthalate acts as tetrakis(monodentate) ligand and links manganese(II) pairs to yield a one-dimensional chain. The manganese(II) ion coordinates with four nitrogen atoms of TPA and two oxygen atoms of two carboxylate groups from two terephthalate ligands and occurred in a distorted octahedral structure. The complex crystallizes in triclinic space group P 1 ̄ , with α=108.673(4)°, β=93.420(5)°, γ=92.342(5)°; a=8.170(2) Å, b=9.904(3) Å, c=15.134(4) Å; V=1155.7(5) Å3; Z=1; R 1=0.0567, wR 2=0.1458. In the temperature range 4–300 K, magnetic measurement shows that the exchange interaction of the two manganese(II) ions is antiferromagnetic, and the values obtained for J, g and zj are −1.20, 1.97 and −0.03 cm−1, respectively.
Keywords: Crystal structure; Mn(II) complex; Terephthalate; Magnetic properties; One-dimensional chain;

Synthesis, spectroscopic and photochemical characterization of phenylthiol-derivatized zinc phthalocyanine complex: 2,3,9,10,16,17,23,24-octa(4-methylphenylthio-)phthalocyaninatozinc(II) [ZnPc(SC6H4CH3)8] (3a) and its alkanethiol derivative, 2,3,9,10,16,17,23,24-octabutylthiophthalocyaninatozinc(II) [ZnPc(SC4H9)8] (3b) are described. Spectroscopic analyses show that 3a has a higher aggregation tendency than 3b in organic solvents. Photochemical studies indicate that 3b is more photostable and more efficient at singlet oxygen generation than 3a.
Keywords: Thio-substituted zinc phthalocyanine; Spectroscopy; Voltammetry; Singlet oxygen; Photostability;

First crystal structure determination and high-frequency EPR study of an organoarsanecopper radical complex by Shengfa Ye; Wolfgang Kaim; Biprajit Sarkar; Brigitte Schwederski; Falk Lissner; Thomas Schleid; Carole Duboc-Toia; Jan Fiedler (1196-1200).
The red radical complex {(μ-bptz)[Cu(AsPh3)2]2}(BF4) 1, bptz=3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, was obtained as a stable species and characterized by X-ray crystallography, spectroelectrochemistry and EPR at 9.5 and 285 GHz. Comparison with the previously reported {(μ-bptz)[Cu(PPh3)2]2}(BF4) 2 reveals longer Cu-element bonds by about 0.1 Å but otherwise a similar “organic sandwich” structure involving intramolecular π(phenyl)–π(tetrazine)–π(phenyl) interactions, a 3+1 coordination at the copper(I) centers, and averaged tetrazine intraring bond distances. Reversible oxidation to a blue dication with an intense MLCT band at 650 nm occurs at −0.24 V vs. Fc+/o. EPR studies show the effect of the higher spin–orbit coupling constant of the As vs. P atoms through slightly larger g anisotropy as determined through high frequency measurements.
Keywords: Arsane ligands; Copper complex; EPR; π Interaction; Radical complex;

A Pd-catalysed Stille coupling of 2,6-diphenyliodobenzene with tributylcyclopentadienyltin gave the sterically constrained ligand precursor cyclopentadienyl-2,6-diphenylbenzene (1). Treatment of this precursor with tetrakis(diethylamido)zirconium(IV) gave the three-legged piano-stool complex [(2,6-Ph2–C6H35-C5H4)Zr(NEt2)3] (2). Complex 2 was characterised by 1H- and 13C{1H}-NMR spectroscopy as well as by X-ray crystallography which showed significant distortions of the three-legged piano-stool geometry as a result of steric interactions with the bulky aryl substituent.
Keywords: Crystal structures; Zirconium complexes; Cyclopentadienyl ligands; Stille couplings;

Catalase and superoxide dismutase mimics for the treatment of inflammatory diseases by Anna E.O. Fisher; Suzette C. Maxwell; Declan P. Naughton (1205-1208).
Conjugation of a metal ion chelator to aromatic amino acids generates a series of novel metal-binding anti-oxidant enzyme mimics. Our catalytic peptoids are designed to suppress oxidative damage via a number of routes. These include: (i) binding redox-active metal ions that further generate/activate RONS, (ii) removal of hydrogen peroxide by catalase activity, (iii) removal of superoxide by superoxide dismutase activity, and (iv) preventing the formation of hydroxyl radicals and peroxynitrite by removal of their precursors [as in (ii) and (iii)]. Thus, the redox-active metal ions are changed from detrimental RONS producers to beneficial RONS scavengers. In conclusion, we present a series of biomimetic peptoids that (i) bind redox-active metal ions, (ii) detoxify RONS and (iii) have potential therapeutic applications in inflammatory diseases.
Keywords: Catalase; Superoxide dismutase; Enzyme mimic; Metal ions;

Six- and four-coordinated zinc(II) complexes exhibit strong blue fluorescent properties by Long Yi; Li-Na Zhu; Bin Ding; Peng Cheng; Dai-Zheng Liao; Shi-Ping Yan; Zong-Hui Jiang (1209-1212).
A new ligand, 4-(p-chlorophenyl)-1,2,4-triazole (pCltrz), and its complexes, [Zn(pCltrz)6]2(ClO4)2  · H2O (1) and [Zn(pCltrz)2Cl2] (2), were synthesized. The structure of 1 exhibits the first case that zinc(II) ion coordinated with six triazole ligands to form octahedral environment. Both 1 and 2 display very strong blue photoluminescence as the result of the fluorescence from the intraligand emission excited state.
Keywords: Zinc complex; Triazole; Crystal structure; Fluorescence properties;

The reaction of the bicyclic anhydride of diethylenetraiamine-pentaacetic acid (DTPAA) with inositol gave diethylenetriamine-inositol-biester-N,N ,N″-triacetic acid (DTPA-BI) (1). (1) was characterized by FAB-MS, 1HNMR, IR and elemental analysis. Its chelates of Gd(III), Fe(III) and Mn(II) holding promise of magnetic resonance imaging (MRI) were synthesized. Gd(III) complex was obtained from Gd2O3 and the acid form of (1). Thermodynamic stability constant and relaxation of Gd(III) complex with DTPA-BI were determined. The spin–lattice relaxivity (R 1=5.6 l mmol−1 s−1) of chelate was slightly larger than that of [GdDTPA]2−. The results showed that the complex is a prospective MRI agent, although thermodynamic stability constant of DTPA-BI K [GdDTPA-BI] =1018.2 was a little less than that of [GdDTPA]2− (K[GdDTPA] 2−=1020.73).
Keywords: Diethylenetriamine-inositol-biester-N,N ,N″-triacetic acid; Thermodynamic stability constant; Relaxivity MRI contrast agent;

A novel coordination polymer [Ba(H2O)4(CuL)2] n (where L=Schiff base derived from 5-bromosalicylaldehyde and glycylglycine) has been synthesized and characterized by X-ray crystallography. The structure reveals the formation of one-dimensional chains, which are assembled further into two-dimensional network by hydrogen bonds between the coordinated water molecules.
Keywords: Ba(II)–Cu(II) complex; One-dimensional chain; Crystal structure; Dipeptide;

Unsolvated “carbons apart” neodymacarborane sandwich stabilized by bis(η6-benzene)potassium cation: a unique dimeric mixed-metal sandwiched ion-pair by Jianhui Wang; Shoujian Li; Chong Zheng; John A Maguire; Wolfgang Kaim; Narayan S Hosmane (1220-1223).
The reaction between NdCl3 and potassium metal in a 1:4 molar ratio in THF, followed by the addition of 2 equivalents of 1,2-(SiMe3)2-1,2-closo-C2B4H4 (1), produced the novel dimeric, mixed-metal sandwiched ion-pair, {2,2,4,4-(SiMe3)4-5,6-[(μ-H)2K(η6-C6H6)2]-1,1-commo-Nd(η5-2,4-C2B4H4)2}2 (2), in 78% yield, after re-crystallization in benzene. The simultaneous cage opening/metalation product 2 was verified by single crystal X-ray diffraction.
Keywords: Ion-pair; Neodymacarborane-sandwich; Bis(η6-benzene)potassium; Cage-opening/metalation; Dimer; Lanthanacarborane-anion; Potassium-sandwich-cation; Mixed-metal; Crystal structure; Synthesis;

A transition metal complex containing pyrazine-2,5-dicarboxylato bridging ligands: a novel three-dimensional manganese(II) compound by Garikoitz Beobide; Oscar Castillo; Antonio Luque; Urko Garcı́a-Couceiro; Juan P. Garcı́a-Teran; Pascual Román; Luis Lezama (1224-1227).
The novel metal-organic polymer [Mn(μ4-pzdc)] n (H2pzdc=pyrazine-2,5-dicarboxylic acid) has been synthesized by the hydrothermal reaction of Mn(NO3)2  · 4H2O with H2pzdc. X-ray diffraction analysis shows that the polymer exhibits an extended three-dimensional network with hexadentated pzdc ligands bridging four manganese(II) atoms. The magnetic measurements show the occurrence of weak antiferromagnetic couplings.
Keywords: Pyrazine bridge; Three-dimensional complex; Manganese complex; Dicarboxylate; Crystal structure; Magnetic properties;

Preparation and catalytic properties of a new dioxomolybdenum(VI) complex covalently anchored to mesoporous MCM-48 by Carla D. Nunes; Martyn Pillinger; Anabela A. Valente; André D. Lopes; Isabel S. Gonçalves (1228-1233).
Reaction of the solvent adduct MoO2Cl2(THF)2 with the 1,4-diazabutadiene ligands RNC(Ph)C(Ph)NR [R = (CH2)2CH3, (CH2)3Si(OMe)3] leads to complexes of the type MoO2Cl2(LL) in good yields at room temperature within a few minutes. The complex bearing the trimethoxysilyl groups was immobilized in the ordered mesoporous silica MCM-48 by covalent bonding. Solid state MAS NMR spectroscopy (13C, 29Si) confirms that the structural integrity of the complex was retained during immobilization, except for loss of methoxide groups due to the reaction with surface silanols. Powder X-ray diffraction (XRD) and N2 adsorption studies of the derivatized material indicate that the textural properties of the support were preserved during the grafting experiment and that the channels remained accessible. The modified material is active and selective in the epoxidation of cyclooctene at 55 °C using tert-butyl hydroperoxide as the oxidant. Stability was checked by recycling the solid catalyst several times. Some activity is lost from the first to second runs, but thereafter stabilizes. The catalytic behavior of the heterogenized catalyst was also compared with that observed in homogeneous phase for the complex with R=(CH2)2CH3.
Keywords: Catalysis; Chelating ligands; Mesoporous materials; Molybdenum; Olefin epoxidation; Oxide complexes;

Synthesis and crystal structure of [ n Bu4N][Er(pic)4] · 5.5H2O: a new infrared emitter by Paula C.R Soares-Santos; Helena I.S Nogueira; Vitor Félix; Michael G.B Drew; Rute A.Sá Ferreira; Luı́s D Carlos; Tito Trindade (1234-1238).
The new erbium(III) complex of picolinic acid (Hpic), [ n Bu4N][Er(pic)4] · 5.5H2O, was synthesized and the crystal structure determined by single-crystal X-ray diffraction. The compound was further characterized using IR, Raman, 1H NMR and elemental analysis. The picolinate ligands (pic) are coordinated through N,O-chelation to the erbium cations, as shown by X-ray diffraction and spectroscopic results, leading to an eight coordinate complex. Photoluminescence measurements were performed for this compound which exhibits infrared emission.
Keywords: Erbium complexes; Picolinic acid; Crystal structure; Photoluminescence;

Microporous solid based solely upon an intermolecular NH ⋯ O and NH ⋯ Cl hydrogen bond network by Satoshi Takamizawa; Ei-ichi Nakata; Teruo Saito; Taka-aki Okamura; Norikazu Ueyama (1239-1242).
A novel porous solid of ruthenium(II, III) dimer complex, [Ru2(p-O2CC6H4NHCOtBu)4Cl], constructed by intermolecularly linking the hydrogen bonds of NH ⋯ O and NH ⋯ Cl was synthesized and the porous structure was crystallographically determined. The dried crystalline solid shows a high BET surface area determined by measuring the adsorption of nitrogen gas and water vapor.
Keywords: Microporous solid; Gas adsorption; Dinuclear Ru complex; Hydrogen bonded network;

For the first time, density functional theory (DFT) calculation was performed on the titled complexes and the calculated geometries are in good agreement with the available experimental data. The decrease in the bond distances (Ln–X) as well as the increase in the Hirshfeld charges and the chemical hardness from La to Lu indicates an increase in ionic character on going from La to Lu. The lanthanide contraction and ionic character of metal–ligand bond are found to follow the order: Ln–X > Ln–Cp > Ln–O.
Keywords: Organolanthanide; DFT; Ionic character; Lanthanide contraction; Charge;

A carboxylate-bridged μ-oxo-bis[diperoxomolybdate(VI)] by Shu-Ya Hou; Zhao-Hui Zhou; Hui-Lin Wan; Seik-Weng Ng (1246-1248).
Carboxylate-bridged dinuclear peroxomolybdate(VI), K3{μ-Acμ-O-[Mo(O2)2O]2} (HAc=acetic acid), which was serendipitously obtained from the hydrogen-peroxide oxidation of potassium lactatoperoxomolybdate(VI), represents the first example of a ligand-stabilized dinuclear Mo2(O2)4(O)3.
Keywords: Molybdate(VI); Peroxo; Acetate; Crystal structure;

A novel copper coordination polymer, Cu(H2O)(1,3-BDC) · H2O was synthesized by a mixed solvothermal reaction of cupric acetate with 1,3-BDC and characterized by single-crystal X-ray diffraction. This compound crystallizes in a tetragonal space group P4/nmm with cell parameters a=19.1411(5) Å, c=6.7881(2) Å, and Z=8. Its structure contains paddle-wheel-like bi-copper clusters with the pseudo-octahedral centers of Cu(II) ion, Cu2O8(H2O)2. Every 1,3-BDC fragment links two such clusters to yield a two-dimensional open structure. It was also characterized by infrared spectroscopy, elemental analysis, inductively coupled plasma analysis, differential thermal and thermal gravimetric analyses.
Keywords: Copper coordination polymer; Solvothermal reaction; Crystal structure;

Mononuclear and dinuclear nickel(II) complexes and heterodinuclear Zn(II)Ni(II) complexes of the ligand 3,4:9,10-dibenzo-1,12-[N,N bis{4-methyl-1-oxa)-6, 6-formyl}-2-benzyldiaza]-5,8-dioxacyclotetradecane were prepared. The structure of the complex [NiL1a] was solved by X-ray crystallography. The electrochemical reduction processes of the mononuclear nickel(II) and the heterobinuclear zinc(II)nickel(II) complexes were irreversible and that the binuclear nickel(II) complexes showed quasireversible reduction processes and irreversible oxidation processes. Kinetics of hydrolysis of 4-nitrophenyl phosphate catalyzed by the complexes showed pseudo first order processes with rate constants in the range 2 × 10−5 s−1 for the mononuclear nickel(II) complexes and in the range 8 × 10−4 s−1 for the homo binuclear nickel(II) and heterobinuclear zinc(II)nickel(II) complexes.
Keywords: Macrocyclic ligands; Binuclear Ni(II) complexes; Electrochemical studies; Hydrolysis of 4-nitrophenyl phosphate;

A 2-D ladder-type polymer, Mn2(NIT2-thz)2Cl4(H2O)2: synthesis, crystal structure and magnetic properties by Li-Ya Wang; Chen-Xi Zhang; Zhan-Quan Liu; Dai-Zheng Liao; Zong-Hui Jiang; Shi-Ping Yan (1255-1258).
A novel ladder-type two-dimensional complex Mn2(NIT2-thz)2Cl4(H2O)2 (NIT2-thz=2-(2-thiazole)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been prepared and characterized structurally. Magnetic measurements show that there are three kinds of antiferromagnetic interactions in the complex.A novel Mn(II)-nitronyl nitroxide-substituted thiazole complex Mn2(NIT2-thz)2Cl4(H2O)2 (NIT2-thz=2-(2-thiazole)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) was synthesized and characterized structurally and magnetically. It crystallizes in the orthorhombic space group Pbca. The complex has dimeric structure where two manganese ions are doubly bridged by chloride ions. Each manganese ion is in a distorted octahedral environment. The complex molecules were connected as two-dimensional ladder-type structure by the intermolecular interaction. Magnetic measurements show that there are three kinds of antiferromagnetic interactions in the compound.
Keywords: Crystal structure; Thiazole nitroxide radical; Manganese(II) complex; Antiferromagnetic interaction;

Crystal structures and spectroscopic behaviour of polymeric copper(II) chloroacetate adducts with 3- and 4-pyridylmethanol by Marcela Múdra; Ján Moncol’; Jozef Švorec; Milan Melnı́k; Peter Lönnecke; Tadeusz Glowiak; Reinhard Kirmse (1259-1265).
The structural and spectroscopic properties for polymeric complexes, Cu(Cl2CHCOO)2(3-PM)2, Cu(Cl3CCOO)2(3-PM)2, Cu(ClCH2COO)2(4-PM)2 and Cu(Cl2CHCOO)2(4-PM)2 (PM=pyridylmethanol), are reported. The characterization is based on elemental analysis, infrared, electronic and EPR spectra. The Cu(Cl2CHCOO)2(3-PM)2 as well as Cu(Cl3CCOO)2(3-PM)2 adopt polymeric structures as revealed by X-ray structure analysis. The polymeric structure of Cu(Cl2CHCOO)2(3-PM)2 is centrosymmetric and centred at the inversion center of the space group P1bar (Z=2), while the structure of Cu(Cl3CCOO)2(3-PM)2 contains two crystallographically independent centrosymmetrical molecules, which are centred at the inversion centres of the space group P21/c (Z=4).
Keywords: Copper; Carboxylate complexes; Crystal structure; Spectral properties; Coordination polymers; Pyridylmethanol;

Reduction of carbon dioxide during the synthesis of metal nano-particles in water by Irena Rusonik; Hurriyet Polat; Haim Cohen; Dan Meyerstein (1266-1268).
An effort was made to synthesize “carbon-free” metal (Fe0, Co0, Ni0) nano-particles via the reduction of their salts with BH4 in aqueous solutions. Surprisingly it was found that when the synthesis is carried out in the presence of CO2, e.g., in aerated solutions, the CO2 is catalytically reduced by BH4 on the surface of the metal particles. Carbon-free metals can be prepared by reduction under an inert atmosphere. Thus metal surfaces might have acted as catalysts for CO2 fixation, probably via the initial formation of carbon clusters, in the reductive atmosphere in the prebiotic era.
Keywords: Carbon dioxide; Metal nano-particles; Reduction; Sodium borohydride;

Host complexes that adapt to their guests: amphitopic receptors by Nancy Yue; Zengquan Qin; Michael C. Jennings; Dana J. Eisler; Richard J. Puddephatt (1269-1271).
Palladium (II) “lantern complexes” with the bis(pyridyl) ligand NN=1,3-C6H4(CONH-3-C5H4N)2, which can act as receptors for either cations or anions by adjusting the conformation of the amide substituents to accommodate the guest, are termed amphitopic receptor.

The hydrothermal reaction of Na2WO4  · 2H2O, ZnCl2, Zn(Ac)2  · 2H2O, 2,2-bipyridine, and H2O gives rise to a novel Keggin unit supported zinc-bipyridyl complex [Zn(2,2-bipy)3]2[ZnW12O40Zn(2,2-bipy)2] · H2O consisting of a novel heteropolyanion [ZnW12O40Zn(2,2-bipy)2]4+ in which the Keggin anion [ZnW12O40]6− acts as a bidentate ligand towards the transition metal cation Zn2+ through a terminal oxygen and a bridging oxygen from the same WO6 octahedron.
Keywords: Hydrothermal synthesis; Polyoxometalates; Zinctungstate; Crystal structure;

Effect of Pb2+ on the photoluminescence characteristics of ZrO2: Mn2+ nanocrystals by Shu Fen Wang; Feng Gu; Meng Kai Lü; Su Wen Liu; Dong Xu; Duo Rong Yuan; Yong Xin Qi (1275-1277).
The photoluminescence (PL) properties of the Mn, Pb co-doped ZrO2 nanocrystals have been investigated in detail. A relatively broad and strong emission band centered at about 640 nm was observed originating from the 4T1 (4G) to the 6A1 (6S) transition of Mn2+. In the presence of Pb2+, the luminescent intensities of the ZrO2: Mn nanocrystals have been greatly enhanced due to the energy transfer from Pb2+ to Mn2+. As a concentration quenching exists, the optimum value of Pb2+ is 5%.
Keywords: ZrO2: Mn, Pb; Nanocrystal; Photoluminescence; Coprecipitation;

The first hetero-binuclear alkoxide of iron and vanadium: structural and spectroscopic features by Giovana G. Nunes; Geraldo R. Friedermann; Marcelo H. Herbst; Ricardo B. Barthem; Ney V. Vugman; J.Elaine Barclay; David J. Evans; Peter B. Hitchcock; G.Jeffery Leigh; Eduardo L. Sá; Jaı́sa F. Soares (1278-1281).
The immediate reaction between [V2(μ-OPri)2(OPri)6] (A) and [Fe2(μ-I)2I2(HOPri)4] (B) in toluene/propan-2-ol gives the novel mixed-metal [FeI2(μ-OPri)2V(OPri)2(HOPri)] (C). Structural, spectroscopic and magnetochemical characterisation are all consistent with a non-oxo vanadium(IV)/high-spin iron(II) formulation; variable-temperature X-band EPR spectra reveal an S=1/2↔S=1 equilibrium involving the vanadium centres in propan-2-ol solution.
Keywords: Non-oxo vanadium(IV); Iron(II); Heterometallic; Alkoxide; Binuclear;

The oxidative addition of PhSe–X molecules (X=Cl or Br) to Pt(II) complexes of formula [PtR(R)(N,N-chelate)] [R, R=Me, CH(CO2Me)2, CH(CO2Me)(CN); N,N-chelate=4,4-(tert-butyl)2-2,2-bipyridine] is described. The reaction quantitatively affords octahedral products [PtR(R)(SePh)(X)(N,N-chelate)], and is highly selective, since only the isomers with -X and -SePh in trans position are obtained. When R=R=CH(CO2Me)2 or R=R=CH(CO2Me)2(CN) an irreversible reductive elimination takes place in solution, giving rise to Pt(II) compounds [PtR(X)(N,N-chelate)] and organoselenium molecules PhSeR.
Keywords: Platinum; Selenium; Oxidative addition; Reductive elimination; Octahedral complexes;