Different Coordination Modes (different + coordination_mode)

Distribution by Scientific Domains

Selected Abstracts

Two novel benzenedicarboxylate-metal complexes: synthesis, crystal structures and fluorescent properties

Yi-Shan Song
Abstract Two novel benzenedicarboxylate,metal complexes, [Sm(nphth)(Hnphth)(H2O)3,H2O]2 and [Zn(nphth)(bipy)(H2O) ,H2O]2 (2) (H2nphth = 3-nitrophthalic acid, bipy = 2,2,-bipyridine), have been synthesized under hydrothermal condition and characterized by single-crystal X-ray diffraction. Both complex 1 and 2 exhibit a dimeric structure, and nphth ligand shows different coordination mode in the f-block and d-block complexes. The fluorescent properties of two complexes are investigated; the results reveal that the two complexes show different kinds of fluorescence. Copyright 2007 John Wiley & Sons, Ltd. [source]

The Variable Binding Modes of Phenylbis(pyrid-2-ylmethyl)phosphane and Bis(pyrid-2-ylmethyl) Phenylphosphonite with AgI and CuI

Fernando Hung-Low
Abstract A series of new bridging phosphane and phosphonite structures forming three- and six-membered rings with the metal centers were synthesized and characterized. The resulting compounds of phenylbis(pyrid-2-ylmethyl)phosphane (1) with the silver(I) salts of trifluoroacetate (tfa,), tetrafluoroborate (BF4,), and trifluoromethanesulfonate (OTf,), and copper tetrakis(acetonitrile) hexafluorophosphate (PF6,) shows the flexibility of the ligand by displaying different coordination modes associated with the electronic and structural characteristics of the corresponding anion. Accordingly, ligand 1 in these complexes displays two different binding modes. With Agtfa and AgBF4 compounds 3 and 4 are obtained where the ligand chelates to two silver atoms that exhibit normalAg,Ag contacts in the range of 2.9 . When AgOTf or Cu(NCCH3)4PF6 are used, one molecule of 1 bridges the metal centers through a phosphorus atom while another is terminally bound. This induces short M,M distances of 2.6871 and 2.568 for 5 and 6, respectively. Similarly, the coordination behavior of the heterofunctional bis(pyrid-2-ylmethyl) phenylphosphonite ligand (2) is reported with Cu(NCCH3)4PF6 (7) and AgBF4 (8) to form two novel discrete molecules. In these complexes 2 coordinates through the P and N atoms, with the difference that in 7 the O atom of one of the carbinol arms is also bound to the Cu. Elemental analysis, variable-temperature multinuclear NMR spectroscopy, single-crystal X-ray diffraction, and low-temperature luminescence studies were carried out to fully characterize the compounds. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Polymers or Supramolecules Generated From a New V-Shaped Bis-monodentate Ligand and the Effect of Steric Hindrance on Coordination Modes of the Ligand

Caihua Zhou
Abstract A new V-shaped bis-monodentate ligand L (L = 2,3,-dipyridylamine) (1) has been designed and synthesized by alkylation reaction of pyridylamine. An investigation of the charge distributions of the coordination atoms and single-point energy calculations of four conformers of ligand L based on the geometry of conformers optimized by the DFT (density functional theory) method was carried out. The results show that the four conformers of ligand L take on two stable and two less stable configurations. Theory forecasts that two relatively stable configurations present in complexes as probable coordination motifs of the ligand, and that steric hindrance of pyridine nitrogen atoms in isomers will affect its coordination ability together with the electronic factor. This forecast has been demonstrated by the coordination chemistry of ligand L, that is, configuration (a) and (b) of the ligand occur in the following reported complexes, which combines with AgI or CuII through two coordination modes (bidentate bridging or a monodentate mode) resulting in coordination polymers {[Ag (L)2]NO3}n (2), [Cu2(L)2(maa)4]n (maa = methacrylic acid) (3), and the mononuclear molecule [Cu(L)4](ClO4)22CH3CH2OH (4). The ligand assumes different coordination modes in the three complexes because of different levels of steric hindrance of the pyridine nitrogen atoms in the conformers. Interestingly, polymers 2 and 3 assume a 1D helical structure and a linear framework, respectively, and 4 has a 2D supramolecular architecture induced from hydrogen bond interactions. In addition, the magnetic properties of 3 have been explored, which shows a strong antiferromagnetic interaction.( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Di-2-pyridyl Ketone Oxime in Zinc Chemistry: Inverse 12-Metallacrown-4 Complexes and Cationic Pentanuclear Clusters

Maria Alexiou
Abstract The use of di-2-pyridyl ketone oxime (Hpko)/X, "blends" (X, = PhCO2,, N3,, NCO,, acac,, NCS,) in zinc chemistry yields neutral tetranuclear and cationic pentanuclear clusters. Various synthetic procedures have led to the synthesis of compounds [Zn4(OH)2(O2CPh)2(pko)4]3MeCN (13MeCN), [Zn4(OH)2(N3)2(pko)4]4DMF (24DMF), [Zn4(OH)2(NCO)2(pko)4]3DMFH2O (33DMFH2O), [Zn4(OH)2(acac)2(pko)4]4CH2Cl2 (44CH2Cl2), [Zn5Cl2(pko)6][ZnCl(NCS)3]2.5H2O1.5MeOH (52.5H2O1.5MeOH) and [Zn5(NCS)2(pko)6(MeOH)][Zn(NCS)4]2.5H2OMeOH (62.5H2OMeOH). The structures of the six complexes have been determined by single-crystal X-ray crystallography. The tetranuclear molecules of 1,4 lie on a crystallographic inversion centre and have an inverse 12-metallacrown-4 topology. Two triply bridging hydroxides are accommodated in the centre of the metallacrown ring. The pko, ligands form a propeller configuration that imposes absolute stereoisomerism with , and , chirality. Two metal ions are in distorted O2N4 octahedral environments, whereas the rest are in severely distorted tetrahedral or trigonal bipyramidal environments. The five Zn ions of the cations of 5 and 6 are held together by six pko, ligands which adopt three different coordination modes; the chloro (5) and isothiocyanato (6) ligands are terminal. The five Zn ions define two nearly equilateral triangles sharing a common apex, and the novel Zn5 topology can be described as two "collapsed" 9-metallacrown-3 structures sharing a common Zn apex. Besides the pentanuclear cations, the structures of 5 and 6 contain slightly distorted tetrahedral [ZnCl(NCS)3]2, and [Zn(NCS)4]2, ions, respectively, with the isothiocyanato ligands binding the metal ion in a virtually linear fashion. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Nitrogen-Rich Compounds of the Lanthanoids: Highlights and Summary

Georg Steinhauser
Abstract In this third part of our research on the 5,5,-azobis[1H -tetrazol-1-ides] (ZT) of the lanthanoids, we present two compounds with La2(ZT)3 moieties with very different coordination modes between the cations and the anions. One La2(ZT)3 -containing compound is interesting, because it contains trimeric La3(ZT)3III cations, which are arranged in a windmill-like structure. Moreover, the first double salt of a ZT compound, namely the carbonate compound La2(ZT)2(CO3),12 H2O, is presented and discussed. Another highlight of nitrogen chemistry is the first molecular structure of a 5-azido-2H -tetrazole (CHN7) molecule, in the form of the spectacular compound Dy2(ZT)3,4 CHN7,24 H2O. This is the first known complete molecular structure of an azidotetrazole molecule (the organic molecule with the highest nitrogen-content: 88.3% N). All compounds have been characterized completely including elemental analyses, vibrational (IR and Raman) spectroscopy, and X-ray crystal-structure determination. We summarize our ,nitrogen-rich compounds of the lanthanoids' project and extensively discuss selected literature on this topic and compare previously published results with ours. [source]

Poly[bis(,-benzene-1,4-dicarboxylato)bis[,-6-(4-pyridyl)-5H -imidazolo[4,5- f][1,10]phenanthroline]dilead(II)]: an interpenetrating ,-Po net

Zhan-Lin Xu
The asymmetric unit of the title compound, [Pb2(C8H4O4)2(C18H11N5)2]n, contains two PbII atoms, two benzene-1,4-dicarboxylate (1,4-bdc) dianions and two 6-(4-pyridyl)-5H -imidazolo[4,5- f][1,10]phenanthroline (L) ligands. Each PbII atom is eight-coordinated by three N atoms from two different L ligands and five carboxylate O atoms from three different 1,4-bdc dianions. The two 1,4-bdc dianions (1,4-bdc1 and 1,4-bdc2) show different coordination modes. Each 1,4-bdc1 coordinates to two PbII atoms in a chelating bis-bidentate mode. Each carboxylate group of the 1,4-bdc2 anion connects two PbII atoms in a chelating,bridging tridentate mode to form a dinuclear unit. Neighbouring dinuclear units are connected together by the aromatic backbone of the 1,4-bdc dianions and the L ligands into a three-dimensional six-connected ,-polonium framework. The most striking feature is that two identical three-dimensional single ,-polonium nets are interlocked with each other, thus leading directly to the formation of a twofold interpenetrated three-dimensional ,-polonium architecture. The framework is held together in part by strong N,H...O hydrogen bonds between the imidazole NH groups of the L ligands and the carboxylate O atoms of 1,4-bdc dianions within different ,-polonium nets. [source]

Poly[(acetone)tetraaqua[,6 -ethyl (dichloromethylene)diphosphonato][,5 -ethyl (dichloromethylene)diphosphonato]tribarium(II)]

Jonna Jokiniemi
The novel title compound, [Ba3(C3H5Cl2O6P2)2(C3H6O)(H2O)4]n, has a polymeric two-dimensional network structure which lies parallel to the (10) plane. The asymmetric unit consists of three independent Ba2+ ions, two of them eight-coordinated and the third nine-coordinated, and two independent ethyl (dichloromethylene)diphosphonate(3,) ligands, one acetone ligand and four aqua ligands. The coordination environments around the BaO8 polyhedra are best described as bicapped trigonal prismatic, while the BaO9 polyhedron is in a distorted tricapped trigonal prismatic geometry. The two diphosphonate ligands adopt different coordination modes. Both ligands chelate three metal cations, but one is coordinated to six metal cations in total and forms two six-membered and one four-membered chelate ring, while the other is coordinated to five metal cations in total and forms one six-membered and two four-membered chelate rings, the fifth unsubstituted O atom remaining uncoordinated. [source]

A novel O,Zn bridging polymer complex of 2,6-bis[bis(carboxylatomethyl)aminomethyl]-4-methylphenolate

Yuan-Yuan Zhang
A new one-dimensional coordination polymer, catena -poly[[acetatohexaaqua{,4 -2,6-bis[bis(carboxylatomethyl)aminomethyl]-4-methylphenolato}trizinc(II)] octahydrate], [Zn3(C17H17N2O9)(C2H3O2)(H2O)6]8H2O, is a trinuclear complex consisting of three zinc centers joined by a phenolate bridge and Zn(H2O)4 units. In each complex polymer unit, the three Zn atoms have different coordination modes. Of the two phenolate-bridged Zn ions, one adopts a distorted octahedral coordination composed of two carboxylate ligands, one tertiary N atom, two water molecules and the bridging phenolate ligand, while the other adopts a pyramidal geometry composed of two carboxylate ligands, one tertiary N atom from another coordination arm, one acetate anion as the counter-anion and the bridging phenolate ligand. The third type of Zn centre is represented by two independent Zn atoms lying on inversion centres. They both have an octahedral coordination consisting of four O atoms from four water molecules and two acetate carbonyl O atoms from the ligand. The latter Zn atoms join the above-mentioned binuclear complex units through O atoms of the carboxylate groups into an infinite chain. Neighboring aromatic rings are distributed above and below the chain in an alternating manner. Between the coordination chains, the Zn...Zn separations are 5.750,(4) and 6.806,(4),. The whole structure is stabilized by hydrogen bonds formed mainly by solvent water molecules. [source]

Synthesis, structure and biological activity of triorganotin 1H -tetrazolyl-1-acetates: cyclic hexamer and linkage coordination polymers

Yun-Fu Xie
Abstract Reaction of 1H -tetrazolyl-1-acetic acid (CHN4CH2CO2H) with (R3Sn)2O or R3SnOH yields triorganotin 1H -tetrazolyl-1-acetates [CHN4CH2CO2SnR3, R = Ph (1), p -tolyl (2), cyclohexyl (3), n -Bu (4) and Et (5)]. 1H -tetrazolyl-1-acetates in these triorganotin derivatives display remarkably different coordination modes, depending on the properties of the organic substituents bonded to the tin atoms. Complex 1 displays a rare cyclohexameric structure by the assembly of the SnN coordination bond, while complex 2 forms a linkage coordination polymer through the intermolecular SnN interactions. The structure of complex 3 is similar to that of complex 2, but the intermolecular SnN interactions are weaker in the former. However, in complex 4, the tetrazolyl nitrogen atoms do not coordinate to the tin atoms. This complex forms a polymeric chain by the unsymmetric bridging carboxylate group. All these complexes exhibit good antifungal activities in vitro against Alternaria solani, Cercospora arachidicola, Gibberella zeae, Physalospora piricola and Botrytis cinerea. The corresponding EC50 values of these complexes were tested. Copyright 2009 John Wiley & Sons, Ltd. [source]

Iron(II) Complexes with Bio-Inspired N,N,O Ligands as Oxidation Catalysts: Olefin Epoxidation and cis -Dihydroxylation

Abstract The Rieske dioxygenases are a group of non-heme iron enzymes, which catalyze the stereospecific cis -dihydroxylation of its substrates. Herein, we report the iron(II) coordination chemistry of the ligands 3,3-bis(1-methylimidazol-2-yl)propionate (L1) and its neutral propyl ester analogue propyl 3,3-bis(1-methylimidazol-2-yl)propionate (PrL1). The molecular structures of two iron(II) complexes with PrL1 were determined and two different coordination modes of the ligand were observed. In [FeII(PrL1)2](BPh4)2 (3) the ligand is facially coordinated to the metal with an N,N,O donor set, whereas in [FeII(PrL1)2(MeOH)2](OTf)2 (4) a bidentate N,N binding mode is found. In 4, the solvent molecules are in a cis arrangement with respect to each other. Complex 4 is a close structural mimic of the crystallographically characterized non-heme iron(II) enzyme apocarotenoid-15,15,-oxygenase (APO). The mechanistic features of APO are thought to be similar to those of the Rieske oxygenases, the original inspiration for this work. The non-heme iron complexes [FeII(PrL1)2](OTf)2 (2) and [FeII(PrL1)2](BPh4)2 (3) were tested in olefin oxidation reactions with H2O2 as the terminal oxidant. Whereas 2 was an active catalyst and both epoxide and cis -dihydroxylation products were observed, 3 showed negligible activity under the same conditions, illustrating the importance of the anion in the reaction. [source]

Syntheses, Structures and Luminescence Properties of Ln-Coordination Polymers Based on Flexible Thiodiacetic Acid Ligand

Xiangyang HOU
Abstract Two novel lanthanide complexes with the formulas [Ln2(tda)3(H2O)2]n [Ln=Sm (1), Dy (2), H2tda=thiodiacetic acid] have been prepared by using the corresponding lanthanide salt and H2tda under hydrothermal conditions. Single crystal X-ray diffraction studies show that the two compounds are isostructural and present a 2D network based on the 1D metallic chain, in which an edge-sharing dinuclear polyhedral [Ln2O16] was found to be the building unit of the 1D chains. Interestingly, in the network, the tda ligands exhibit two different coordination modes, including the mode La: bis(syn,syn -bridging bidentate, chelating-bridging tridentate), and mode Lb: bis(chelating- bridging tridentate, syn, anti- bridging bidentate). Furthermore, through the tda ligand in modes La and Lb, the 1D metallic chains are cross-linked to generate a 2D network structure with (3,4,5,6)-connected (4768)(4466)(456)- (46)(43) topology. Photoluminescence measurements indicate that the dysprosium complex is yellow emitters, and the samarium complex shows salmon pink light emission in the solid state at room temperature. [source]

Hydrothermal Synthesis, Crystal Structures and Photoluminescence of Two Novel Metal-organic Supramolecular Frameworks Based on Mixed Ligands of Dipyrazino[2,3- f:2,,3,-h]quinoxaline and Pyridine-2,5-dicarboxylic Acid

Abstract Two novel metal-organic frameworks [Zn2(Dpq)2(2,5-pda)2(H2O)2]2H2O (1) (dipyrazino[2,3- f:2,3,- h]quinoxaline=Dpq) and [Cd2(Dpq)2(2,5-pda)2]2H2O (2) (pyridine-2,5-dicarboxylic acid=2,5-H2pda) have been obtained from hydrothermal reactions of two different metal(II) nitrates with the same mixed ligands Dpq and 2,5-H2pda, and structurally characterized by elemental analyses, TG, IR spectroscopy, and single-crystal X-ray diffraction analyse. Single-crystal X-ray analyses show that the metal ions are bridged by different coordination modes of 2,5-pda to form a dimer in 1, 2D rhombic grid in 2, respectively. In the compound 1, adjacent dimers are packed through hydrogen bonds and - aromatic stacking interactions to form a distorted , -Po supramolecular structure. In the compound 2, adjacent polymer layers are further linked by hydrogen bonds to form a distorted , -Po 3D supramolecular framework stabilized by - stacking interactions. The different structures of compounds 1 and 2 illustrate the influence of the metal ions and ligands on the self-assembly of polymeric coordination architectures. In addition, the title compounds exhibit blue emission in the solid state at room temperature. [source]

One-Dimensional Network Constructed by Salicylate and Phenanthroline Ligands with Copper (II)

Lag-Guan Zhu
Abstract A novel complex, [Cu2 (phen) (sal) (Hsal)2]n (1), was synthesized and structurally characterized. The base dimeric units are hold by sal ligands and extended into 1-D network. The carboxylate groups of salicylates coordinate to the central ion in three different coordination modes: chelating, bridging and bridging-chelating. In the case of bridging-chelating of the carboxylate group of the salicylate, all three oxygen atoms of salicylate are bidentately coordinated to copper ion, namely, ,4 -,3 binding mode. [source]