Inorganic Chemistry Communications (v.8, #6)

Contents List (iii-viii).

The syntheses, crystal structures and optical limiting effects of transition metal adducts bridged by bipyridyl-based ligands by Yunyin Niu; Ning Zhang; Yinglin Song; Hongwei Hou; Yaoting Fan; Yu Zhu (495-499).
Reactions of HgI2 and MnCl2 with N,N′-bis(3-pyridylmethyl)thiourea (bpt) give two adducts [HgI2(bpt)]2 1 and [MnCl2(bpt)2] n  · 2CH3OH 2. 1 is a binuclear metallocyclic compound; 2 possesses regular 1-D double chain structure with bridging bpt ligands. Their optical limiting threshold was determined to be 1.0 and 0.7 J cm−2, which is comparable to those of many heterothiometallates.Two novel compounds [HgI2(bpt)]2 (1) and [MnCl2(bpt)2] n  · 2CH3OH (2) (bpt =  N,N′-bis(3-pyridylmethyl)thiourea), have been synthesized via the self-assembly reaction in solution. Complex 1 possesses a two–dimensional supramolecular network formed by hydrogen bonds among repeating [HgI2(bpt)]2 dimeric units. Complex 2 is a one-dimensional coordination polymer containing uniform –MnCl2–(bpt)2–MnCl2–(bpt)2– double chain. Their limiting thresholds were determined to be 1.0 J cm−2 for 1 and 0.7 J cm−2 for 2 and the results testified that the skeletal structure and constituted metal nuclearity have a strong impact on the NLO properties of the complexes.
Keywords: Bipyridyl-based ligand; Coordination polymer; Double chain structure; Optical limiting effects;

The photochemical oxidative addition of GeCl4 to [W(CO)422-1,5-C8H12)] affords the new cyclooctadiene complex of tungsten(II) [WCl(GeCl3)(CO)322–1,5-C8H12)] (1), which in CH2Cl2/CH3CN solution transforms to the dimeric compound [(μ-Cl)2W2(GeCl3)2(CO)6(NCMe)2] (2). The molecular structure of compound 2 was determined by single-crystal X-ray diffraction studies.The photochemical oxidative addition of 1 equiv. of GeCl4 to [W(CO)422-1,5-C8H12)] affords the very labile seven-coordinate complex of tungsten(II) [WCl(GeCl3)(CO)322-1,5-C8H12)] (1). The structure of compound 1 has been established by IR and 1H NMR spectroscopic methods. A very labile 1,5-cyclooctadiene ligand of 1 in dichloromethane/acetonitrile solution leaves the coordination sphere of tungsten to give a dimeric seven-coordinate compound of tungsten(II) [(μ-Cl)2W2(GeCl3)2(CO)6(NCMe)2] (2). The crystal structure of a new dimeric compound containing W–Ge bonds (2) was determined by X-ray diffraction studies.
Keywords: Tungsten; Germanium; Heterobimetallic compound; Cyclooctadiene complex; Crystal structure; NMR;

Interaction of molybdenum oxomethoxide and bismuth chloride in toluene/acetonitrile media leads to the formation of an unusual ionic salt [ Mo ( OMe ) 5 ( CH 3 CN ) ] + Bi 2 Cl 7 - (1), providing the first example of an isolated mononuclear alkoxide cation.Interaction of molybdenum oxomethoxide and bismuth chloride in toluene/acetonitrile media leads to the formation of an unusual ionic salt [Mo(OMe)5(CH3CN)]Bi2Cl7 (1), providing the first example of an isolated mononuclear alkoxide cation, [Mo(OMe)5(CH3CN)]+ with rather uniform Mo–O(Me) bond lengths. The product can be isolated with moderate yields and only from solutions with considerable excess of the molybdenum reactant (Mo:Bi ≈ 2:1) after refluxing of the reaction mixture, which indicates disproportionation of MoO(OMe)4 in solution into MoO2(OMe)2 and Mo(OMe)6 as a crucial step in its formation.
Keywords: Metal alkoxide; Heterometallic complexes; Molecular precursor; Catalysis;

Crystal structure and mesogenic property of an iron(II) complex with a terpyridine derivative ligand by Shinya Hayami; Kazutoshi Danjobara; Yuji Shigeyoshi; Katsuya Inoue; Yoshihiro Ogawa; Yonezo Maeda (506-509).
Iron(II) compound [Fe(C16-terpy)2](BF4)2 (1) was synthesized, and exhibited liquid crystal transition. The thermodynamically stable form of the compound 1 is a low-spin state at room temperature. The single crystal X-ray analysis revealed the structure for iron(II) compound [Fe(C16-terpy)2](ClO4)2  · acetone (1′). It can be understood that the low-spin iron(II) compound 1 is new type metallomesogen.Iron(II) compound [Fe(C16-terpy)2](BF4)2 (1) was synthesized, and exhibited liquid crystal transition. The thermodynamically stable form of the compound 1 is a low-spin state at room temperature. The single crystal X-ray analysis revealed the structure for iron(II) compound [Fe(C16-terpy)2](ClO4)2  · acetone (1′). It can be understood that the low-spin iron(II) compound 1 is new type metallomesogen.
Keywords: Metallomesogen; Iron(II) complex;

Cu(I) coordination complex with TTF-based radical cation ligand by Sun-Young Kwon; Jang-Hoon Cho; Hong-In Lee; Uk Lee; Dong-Youn Noh (510-512).
A novel dimeric Cu(I) complex with mono-functionalized TTF derivative, [(CET-EDTTTF)CuBr2]2, was prepared and characterized by X-ray structure analysis, EPR spectroscopy and electrical conductivity measurement. This complex is forming a chain-like structure through the short intermolecular S⋯S contacts between two [CET-EDTTTF] •+ ligands.A single crystal of a dimeric Cu(I) complex with the mono-functionalized TTF derivative, [(CET-EDTTTF)CuBr2]2 (CET-EDTTTF = 4-(cyanoethylthio)-4′,5′-(ethylenedithio)tetrathiafulvalene), was prepared through the slow-diffusion of CET-EDTTTF and Cu(I)Br, and characterized by X-ray structure analysis and EPR spectroscopy. Detailed structural and EPR investigations revealed that the neutral CET-EDTTTF ligand is oxidized to its radical cation during complexation. Two [CET-EDTTTF] •+ ligands are facing each other through short intermolecular S⋯S contacts forming a linear chain structure.
Keywords: Cu(I) complex; TTF; Radical cation; X-ray structure; EPR;

Tuning the redox properties of a 1-D supramolecular array via selective deprotonation of coordinated imidazoles around a Mn(II) center by Brian S. Hammes; Bryan J. Damiano; Paul H. Tobash; Melanie J. Hidalgo; Glenn P.A. Yap (513-516).
A novel 1-D supramolecular array is reported containing neural Mn(II) building blocks. Upon selective deprotonation of the cationic analog, [Mn(H2 2)2]+2, the redox potential of [Mn(H2)2] shifts significantly more negative. However, both complexes self-organize into very similar 1-D zigzag ribbons in the solid state.A neutral 1-D supramolecular array containing [Mn(H2)2] building blocks was synthesized by the selective deprotonation of two coordinated imidazole moieties from the cationic Mn(II) complex, [Mn(H2 2)2]2+. Upon deprotonation the redox potential of [Mn(H2)2] shifts significantly more negative, when compared to the cationic Mn(II) complex. However, X-ray crystallographic studies done on both complexes show a very similarly distorted octahedral geometry around the Mn(II) ion. Interestingly, while [Mn(H2)2] lacks both charge and counterion to assist in crystal packing, both the neutral and cationic complexes self-organize, using primarily π–π and edge-to-π aryl interactions, into very similar 1-D zigzag ribbons in the solid-state.
Keywords: Mn(II) complexes; Imidazole; Selective deprotonation; 1-D Supramolecular array;

A simple synthesis of isotopically pure 2,2′-dipyridyl-d 8 by Edith C. Glazer; Brinn Belyea; Yitzhak Tor (517-519).
A simple synthesis of bpy-d 8 is reported. The ligand is formed via a dedeuteration reaction of pyridine-d 5 in a process that is convenient, safe, and results in high isotopic purity.Isotopically pure bpy-d 8 is formed via a dehydrogenation reaction of pyridine-d 5 in a process that is convenient and safe.
Keywords: bpy; Coordination compounds; Deuterium; NMR; Ruthenium;

The carcinogenic Cr(VI) can be effectively reduced into Cr(III) under UV irradiation in the presence of polyoxometalate.Reduction of Cr(VI) into Cr(III) was examined under UV light irradiation (λ  > 320 nm) in the aerated aqueous solution of four Keggin-type polyoxometalates (POM). All the POMs were effective to initiate the Cr(VI) photoreduction, but they exhibited notably different activity, following the order of H3PW12O40  ≫ H4SiW12O40  > H4GeW12O40  > H3PMo12O40. Whereas the thermodynamics favored Cr(VI) reduction by each reduced POM, the observed order in photoactivity was not in agreement with the one expected from POM redox potentials. Instead, the relative photoactivity among four POMs was exactly the same as those observed for photodegradation of propan-2-ol and textile dye X3B. It was proposed that generation of the reduced-POM was the rate-determining step both for Cr(VI) reduction and for organic oxidation in water.
Keywords: Polyoxometalate; Dichromate; Photoreduction;

New manganese (II) 2d-polymer with deprotonated hydroxytetrazine bridges by M.A. Kiskin; A.A. Sidorov; I.G. Fomina; G.L. Rusinov; R.I. Ishmetova; G.G. Aleksandrov; Yu.G. Shvedenkov; Zh.V. Dobrokhotova; V.M. Novotortsev; O.N. Chupakhin; I.L. Eremenko; I.I. Moiseev (524-528).
New antiferromagnetic hydroxytetrazine bridged manganese (II) 2D-polymer [Mn(μ-N,N′,O-3,5-Me2C3HN2C2(O)N4)2] n (2) has been prepared.A reaction of pivalate polymer [Mn(OOCCMe3)2(EtOH)] n (1) with 3-hydroxy-6-(3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazine (2, L) in EtOH solution under inert atmosphere gives rise to an antiferromagnetic 2D-polymer [Mn(μ-N,NO-3,5-Me2C3HN2C2(O)N4)2] n (4). According to the X-ray analysis data, M(L–H)2 units form a 2D-infinite network in the lattice of compound 4 where L–H is a starting deprotonated hydroxytetrazine. The reaction of 1 with bis[3,5-(dimethylpyrazolyl)]-1,2,4,5-tetrazine (3) in MeCN solution in air results in an antiferromagnetic hexanuclear pivalate cluster Mn64-O)2(μ-OOCCMe3)10(L1)4 (5) where L1 is a dimethylpyrazole molecule – product of hydrolytic splitting of initial bispyrazolyltetrazine.
Keywords: Manganese (II) coordination polymer; X-ray structure; Magnetic properties;

A luminescent polymeric silver(I) coordination tubular helicate by Lei Han; Daqiang Yuan; Yanqing Xu; Mingyan Wu; Yaqiong Gong; Benlai Wu; Maochun Hong (529-532).
A new luminescent polymeric silver(I) coordination polymer, {[Ag(tptb)(MeCN)]ClO4} n (1), (tptb = 2,4,6-trimethyl-1,3,5-tris(2-pyrimidinylthiomethyl)benzene), was synthesized and characterized to be a isolated, 1D tubular helicate.A new polymeric silver(I) coordination polymer, {[Ag(tptb)(MeCN)]ClO4} n (1), (tptb = 2,4,6-trimethyl-1,3,5-tris(2-pyrimidinylthiomethyl)benzene), was synthesized by self-assembly reaction of tptb and AgClO4, and structurally characterized to be a isolated, 1D tubular helicate. 1 is luminescent and displays an emissive maximum at 510 nm in the solid state at room temperature.
Keywords: Silver compound; Tubular helicate; Luminescence; Coordination polymer;

Old ligands with new coordination chemistry: Linear trinuclear mixed oxidation state cobalt(III/II/III) complexes and their mononuclear “ligand” cobalt(III) complexes featuring 2-pyridyloximates by Theocharis C. Stamatatos; Aidan Bell; Paul Cooper; Aris Terzis; Catherine P. Raptopoulou; Sarah L. Heath; Richard E.P. Winpenny; Spyros P. Perlepes (533-538).
A family of novel linear, trinuclear mixed-valence CoIIICoIICoIII clusters have been synthesised employing 2-pyridyloximato ligands; the mononuclear “ligand” CoIII units of the trinuclear clusters have also been prepared and characterised.Reaction schemes involving 2-pyridyloximes, (py)C(R)NOH, CoII sources and counterions X in various solvents lead to the new family of linear trinuclear clusters [ Co 3 III , II , III { ( py ) C ( R ) NO } 6 ] X 2 (py = 2-pyridyl group; R = H, Me, Ph; X = ClO4, PF6). The outer metal centres are low spin, octahedral CoIII ions and are coordinated by three N,N′-bound 2-pyridyloximato ligands; each of these outer CoIII complexes acts as a tridentate chelating “ligand” to the central CoII ion, which adopts an octahedral geometry with six oxygen donor atoms. The CoIII “ligands” have been individually prepared and the reaction of [CoIII{(py)C(Me)NO}3] with Co(ClO4)2  · 6H2O leads to the isolation of [ Co 3 III , II , III { ( py ) C ( Me ) NO } 6 ] ( ClO 4 ) 2 .
Keywords: Cobalt(II) complexes; “Complexes as ligands” strategy; Mixed-valence cobalt(II/III) complexes; 2-Pyridyloxime ligands; Trinuclear cobalt clusters;

A self-assembled molecular ladder with Cu(H2O)4 units as cross rungs by Ben-Yong Lou; Da-Qiang Yuan; Ben-Lai Wu; Lei Han; Fei-Long Jiang; Mao-Chun Hong (539-542).
A self-assembled 1D molecular ladder {[Cu2(sasp)2Cu(H2O)4] · 0.5H2O} n (1) with Cu(H2O)4 units as cross rungs and sasp–Cu–sasp–Cu chains as side rails displays strong antiferromagnetic interactions within Cu3O2 and weak interunit ferromagnetic interactions. Interchain hydrogen bonds result in weak antiferromagnetic interactions.The self-assembly of salicylaldehyde, d,l-aspartic acid and Cu(NO3)2  · 3H2O gave a 1D molecular ladder {[Cu2(sasp)2Cu(H2O)4] · 0.5H2O} n (1) in which Cu(H2O)4 units serve as cross rungs and two sasp–Cu–sasp–Cu chains with opposite chirality serve as side rails. Compound 1 displays strong antiferromagnetic interactions within Cu3O2 trinuclear units and weak interunit ferromagnetic interactions. Interchain hydrogen bonds result in weak antiferromagnetic interactions.
Keywords: Cu(II); N-Salicylideneaspartic acid; Molecular ladder; Antiferromagnetic; Ferromagnetic; Hydrogen bonding;

Self-assembly of a pseudo-tetrahedral Zn(II) complex with a chiral reduced Schiff base into a helical superstructure by Vamsee Krishna Muppidi; Panthapally S. Zacharias; Samudranil Pal (543-547).
A pseudo-tetrahedral complex [ZnL2] with a chiral reduced Schiff base (HL) has been described. The crystal structure reveals right-handed (Δ) absolute configuration of the bis chelate and a right-handed (P) helical assembly of the molecules via intermolecular hydrogen bonding interactions.A pseudo-tetrahedral Zn(II) complex with an N,O-donor chiral reduced Schiff base N-(2-hydroxy-5-nitrobenzyl)-(R)-α-methylbenzylamine (HL) crystallize in the non-centrosymmetric space group P31. The [ZnL2] molecules having the Δ configuration assemble via intermolecular N–H⋯O and C–H⋯O interactions into a right-handed 31 helix.
Keywords: Zinc(II) complex; Tetrahedral; Chiral; Crystal structure; Helical;

A trinuclear cyanamidonitrate–copper(II) complex bridged by imidazolato ligands by Roman Boča; Mária Hvastijová; Jozef Kožı́šek; Marián Valko; Helmut Ehrenberg; Hartmut Fuess; Wolfgang Haase; Ingrid Svoboda; Rüdiger Werner (548-551).
Cyanamidonitrate (can  = NO2N(CN)) forms with copper(II) ions and neutral base (Him  = imidazole) a trinuclear complex of the linear type [(can)(Him)3Cu(μ-im)Cu(Him)2(NO3)2(μ-im)Cu(Him)3(can)]. The terminal Cu atoms are pentacoordinated, whereas the central Cu atom has a strongly elongated octahedral coordination The magnetic susceptibility measurements confirm that the exchange coupling constants of the adjacent Cu centers is strongly antiferromagnetic (J/hc  = −115 cm−1). The magnetization per complex is M  = 0.73 μB at B  = 5 T and T  = 5 K.Cyanamidonitrate (can  = NO2N(CN)) forms with copper(II) ions and neutral base (Him  = imidazole) a complex of the composition [Cu3(Him)8(im)2(NO3)2(can)2] where im stands for the imidazolato (deprotonated imidazole) ligand. The crystal structure reveals three Cu(II) atoms linked by two imidazolato groups in this trinuclear complex of the linear type [(can)(Him)3Cu(μ-im)Cu(Him)2(NO3)2(μ-im)Cu(Him)3(can)]. The terminal Cu atoms are pentacoordinated, whereas the central Cu atom has a strongly elongated octahedral coordination. The magnetic susceptibility measurements confirm that the exchange coupling constants of the adjacent Cu centers is strongly antiferromagnetic (J/hc  = −115 cm−1). The magnetization per complex is M  = 0.73 μ B at B  = 5 T and T  = 5 K.
Keywords: Cyanamidonitrate; Copper(II) complex; Structure; Magnetism;

In the acetonitrile (or methanol) solution amphetamine or methamphetamine was selectively and quantitatively converted into the corresponding N-formyl derivatives in the presence of Cu(bdpg)Cl2, triethylamine and hydrogen peroxide; (bdpg)=N,N-bis-(2-pyridyl-methyl)-β-alanineamide..We have observed that in the acetonitrile solution amphetamine or methamphetamine was selectively and quantitatively converted into the corresponding N-formyl derivatives in the presence of Cu(bdpg)Cl2, triethylamine and hydrogen peroxide; (bdpg) =  N,N-bis-(2-pyridyl-methyl)-β-alanineamide. This will give valuable information to establish the metabolic pathways of amphetamine or methamphetamine in human body.
Keywords: Drug metabolism; Amphetamine; Methamphetamine; Copper(II) chelate; Oxidation reaction;

A manganese coordination polymer [Mn2(NTC)(H2O)2] n , where NTC is 1, 4, 5, 8-naphthalenetetracarboxylate anion, has been synthesized by slow diffusion of manganese chloride and H4 NTC. Mn(II) ions are bridged by one coordinated water and two carboxylate groups in syn–syn mode to form infinite chains, which are further cross-linked by the naphthalene spacers of the NTC to produce 3-D extended network with open-channels. An antiferromagnetic coupling interaction between adjacent manganese ions dominates the magnetic property of the compound.A manganese coordination polymer [Mn2(NTC)(H2O)2] n , where NTC is 1,4,5,8-naphthalenetetracarboxylate anion, has been synthesized by slow diffusion of manganese chloride and H4NTC. Mn(II) ions are bridged by one coordinated water and two carboxylate groups in synsyn mode to form infinite chains, which are further cross-linked by the naphthalene spacers of the NTC to produce 3-D extended network with open-channels. An antiferromagnetic coupling interaction between adjacent manganese ions dominates the magnetic property of the compound.
Keywords: Manganese(II) complex; 1,4,5,8-Naphthalenetetracarboxylate; Magnetic; Crystal structure; Coordination polymer;

Heteroleptic ruthenium(II) complexes based on 6,6′-disubstituted 4,4′-bipyrimidines: New room temperature red-emitting species by Elena Ioachim; Elaine A. Medlycott; Garry S. Hanan; Frédérique Loiseau; Vittorio Ricevuto; Sebastiano Campagna (559-563).
New Ru(II) complexes based on 6,6′-disubstituted 4,4′-bipyrimidines emit in the red at λ max  > 780 nm are easily synthesized and modified.A new series of heteroleptic ruthenium(II) complexes based on 6,6′-disubstituted 4,4′-bipyrimidines (bpm) and two 2,2′-bipyridine (bpy) ligands have been prepared and their spectroscopic and electrochemical properties have been investigated. The complexes exhibit Ru-to-bpm metal-to-ligand charge transfer (MLCT) absorptions centered at about 540 nm and Ru-to-bpy MLCT absorptions centered at about 435 nm. The new complexes are emissive at room temperature in fluid solution and they are among the longest wavelength emitters (λ max  > 780 nm) based on tris-bidentate mononuclear Ru(II) complexes known.
Keywords: Ruthenium complexes; Luminescence spectroscopy; N ligands;

A new heterospin complex 1, [Cu2(oxpn)(NITPBA)2], derived from trans-oxamido-bridged copper(II) binuclear units [Cu2(oxpn), oxpn =  N,N′-bis(2-aminopropyl)oxamide] and carboxyl-substituted nitronyl nitroxide, (NITPBAH = 2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide), has been synthesized and characterized structurally and magnetically.A new heterospin complex 1, [Cu2(oxpn)(NITPBA)2], derived from trans-oxamido-bridged copper(II) binuclear units [Cu2(oxpn), oxpn =  N,N′-bis(2-aminopropyl)oxamide] and carboxyl-substituted nitronyl nitroxide, (NITPBAH = 2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide), has been synthesized and characterized structurally and magnetically. The complex 1 is a four-spin system. The magnetic susceptibility of 1 was measured over the range 2–300 K, which shows that there are unusually moderate antiferromagnetic-interactions between two copper(II) ions bridged by the oxamato bridge.
Keywords: Copper(II) complex; Heterospin; Trans-oxamido-bridged; Crystal structure; Antiferromagnetism;

The new binuclear complex [Cu(hfac)2(bpmu)]2 has been isolated by treatment of Cu(hfac)2  · H2O with bpmu. The single crystal X-ray structure reveals its dimeric nature and that the units are bonded through strong intra- and intermolecular O=C(N–H)2⋯O=C hydrogen bonds. The formation of the discrete species can be considered as the insertion of the bulky cis-{Cu(hfac)2} fragments into the prearranged hydrogen bonded pattern provided by the bpmu tecton through the O=C(N–H)2⋯O=C moieties.A novel binuclear metallacyclic complex, [Cu(hfac)2(bpmu)]2, was isolated by reacting copper(II) hexafluoroacetylacetonate with the bpmu ligand. The crystal structure reveals the presence of dimetal units with the Cu(II) centers in a six-coordinate environment and bridged by the bpmu spacers. The crystal consists of a racemate with the two copper(II) ions of one dimer molecule carrying either a ΔΔ or ΛΛ configuration. The pyridyl-urea-based spacers are connected intramolecularly by the expected strong urea-based hydrogen bonds O=C(N–H)2⋯O=C. The same type of H-bonds allows the molecular units of the same chirality to assemble forming supramolecular columns. This conformationally defined array and hydrogen-bonding network, together with the bulky properties of the fragment {Cu(hfac)2}, were used as a pre-programmed supramolecular information for controlling the formation of discrete species.
Keywords: Dimeric copper(II) complexes; Polypyridine complexes; N,N′-bis(3-pyridylmethyl)urea; Supramolecular chemistry; Hydrogen bonded assembly;

Syntheses, crystal structures and properties of two Mn(II) complexes of DTPA-bisamide derivative by Ying-Chun Liu; Shu-Lan Ma; Qian-Ling Guo; Jing Zhang; Miao-Qiong Xu; Wen-Xiang Zhu (574-577).
Two new Mn(II) complexes of DTPA-bisamide derivative (H5L), MnH3L · CH3OH · 2.5H2O (1) and {[Mn2.5L(H2O)8] · 5.25H2O} n (2) were synthesized and structurally characterized. X-ray structure analyses show that the two complexes have quite different structures. The relaxivity of the two complexes were determined.Two new Mn(II) complexes of DTPA-bisamide derivative ligand (H5L), MnH3L · CH3OH · 2.5H2O (1) and [Mn2.5L(H2O)8] · 5.25H2O (2) were synthesized and structurally characterized. X-ray structure analyses showed that the two complexes have quite different structures. In complex 1, Mn(II) cation adopts a novel seven-coordinate distorted pentagonal bipyramid polyhedron, while in complex 2, four different Mn(II) coordination environments are observed and form a novel 1-D zigzag coordination chain. Complexes 1 and 2 construct the 2-D and 3-D supramolecular architectures through versatile hydrogen bond interactions, respectively. The relaxivity of the two complexes were also determined. The higher R 1 value of 2 means that it may be applied in magnetic resonance imaging contrast agents.
Keywords: Supramolecular structure; Hydrogen bond; Crystal structure; DTPA derivative; Relaxivity study;

The succinamate(−1) ligand in 4f-metal chemistry: First example of amide coordination in the double-chain 1D coordination polymer catena-aquatris(succinamato(−1))erbium(III) by Argyro Messimeri; Vassilios Nastopoulos; Aris Terzis; Catherine P. Raptopoulou; Christos Papadimitriou; Spyros P. Perlepes (578-584).
Compound [Er(LH)3(H2O)] n , where LH is the monoanion of succinamic acid, is the first binary metal/LH complex, the first example of a succinamato metal complex in which amide coordination is realized and the first example of a polymeric LH complex of any metal. The LH ligands adopt three different coordination modes and the complex has a double-chain, ladder-like architecture.Two new 1D lanthanide(III) coordination polymers are reported which feature succinamate(−1) ligands (LH) that exhibit three different coordination modes. Compound 1 ∞ [ Er ( LH ) 3 ( H 2 O ) ] (1), which has been structurally characterized by single-crystal X-ray crystallography, is the first binary metal/LH complex, the first example of a succinamato(−1) metal complex in which amide coordination of LH is realized and the first example of a polymeric LH complex of any metal. The erbium(III) compound and its holmium(III) analog 2 have been studied by a variety of physical and spectroscopic techniques.
Keywords: Coordination polymers; Crystal structure; Dodecahedral coordination geometry; Erbium(III) complexes; f–f spectra; Succinamate(−1) ligand;