Synthesis,X-ray crystal structure and DFT studies of cobalt(II) and vanadium(V) complexes with N,N,O-tridentate aroyl-hydrazone based ligand

A new aroyl-hydrazone, 2-pyridine carboxaldehyde-derived hydrazone ligand and its cobalt(II) (1) and vanadium(V) (2) complexes were prepared. The structures of these compounds were investigated using elemental analysis, spectral (IR, UV), and X-ray diffraction measurements. The electrochemical properties of the complexes were studied by cyclic voltammetry. The hydrazone ligand acted as tridentate and coordinated to vanadium and cobalt via N-imine, N-pyridine, and O-benzohydrazide atoms. The Co(II) complex crystallizes in the monoclinic system, space group P2₁/c, and has a binuclear structure. Chloride ions behave as the linking bridge and a tridentate hydrazine ligand HL and water as the terminal capping ligands. The central Co(II) ion has distorted octahedral geometry. The vanadium(V) complex crystallizes in the monoclinic crystal system, space group P2₁/n, and can be described as having highly distorted trigonal-bipyramidal coordination. The geometries and electronic properties of the complexes were also obtained using DFT and TD-DFT calculations.     

The Crystal and Molecular Structure of a New Calcium(II) Complex with Pyridine-2,6-DiCarboxylate,Water and Nitrate Ligands

Crystals of {catena-[μ-aqua-O]bis[μ-pyridine-2,6-dicarboxylato-O,N-O']} {[monoaqua-nitrato, O-calcium(II)] [diaqua-calcium(II)]} contain dimeric units composed of two calcium(II) ions and two ligand molecules, in which the calcium ions are bridged by two bidentate oxygen atoms, each donated by one carboxylic group of the ligand. The Ca(II) ion is also coordinated by one oxygen atom of the second carboxylate group and the hetero-ring nitrogen atom belonging to the same ligand molecule. The dimers form molecular chains through protons situated at the symmetry centers halfway between the non-bridging carboxylate oxygen atoms. In addition, both calcium ions in the dimer are bridged to calcium ions in adjacent dimers - each by a pair water oxygen molecules giving rise to two-dimensional molecular sheets. Coordination of the Ca ion in the dimer is completed either by two water oxygen atoms or by one water oxygen atom and an oxygen atom donated by a nitrate group. The molecular sheets are held together by an extended system of hydrogen bonds.     

Dimeric Molecules in the Crystals of a Calcium(II) Complex with Pyridine-2,6-Dicarboxylate and Water Ligands

The crystals of bis[ w -pyridine-2,6-dicarboxylato-O,N,O')]bis[trisaqua-calcium(II)] di(pyridine-2,6-dicarboxylic acid) contain dimeric molecules composed of two calcium(II) ions and two ligand molecules. Calcium ions are bridged by two bidentate oxygen atoms each donated by one carboxylic group of the ligand [Ca―N 2.467(2)Å], a monodentate oxygen atom of the second carboxylate group of the ligand [Ca―N 2.484(2)Å] and three oxygen atoms donated by the water molecules [mean Ca―O 2.388(2)Å]. The coordination polyhedron is a distorted pentagonal bipyramid. Acid molecules were found to be located in the space between dimers and involved in an extended network of hydrogen bonds.     

The Crystal Structures of Two Calcium(II) Complexes with Pyrazine- 2,6-Dicarboxylate and Water Ligands

The structure of catena-{bis[(μ-aqua)(diaqua)(pyrazine-2,6-dicarboxylato-O,N-μ-O')](calcium(II)} consists of dimeric units composed of two calcium(II) ions, two ligand molecules and six water molecules. The calcium ions are bridged by two bidentate oxygen atoms, each donated by one carboxylic group of the ligand. The Ca(II) ion is also coordinated by one oxygen atom of the second carboxylate group and the hetero-ring nitrogen atom belonging to the same ligand molecule. Both calcium ions in a dimer are bridged to the Ca(II) ions in adjacent dimers by a pair of water molecules forming infinite molecular ribbons. In addition, each Ca(II) ion is coordinated by three water molecules; one of them is used for bridging the adjacent dimer. The coordination polyhedron around the Ca(II) ion is a pentagonal bipyramid with two apices above and one apex below the equatorial plane. The same molecular pattern is observed in the structure of catena-{bis[(μ-aqua)(diaqua)(pyrazine-2,6-dicarboxylato-O,N-μ-O')](calcium(II)} dihydrate which, in addition, contains two solvation water molecules per unit cell. In both compounds the molecular ribbons are held together by extended systems of hydrogen bonds.     

X-Ray Diffraction Study on Manganese(II) Complexes with Thiophene-2-Carboxylate and Furan-3-Carboxylate Ligands

Abstract

Mn(II) cations in the crystals of trisaquobis(μ-thiophen-2-carboxylato-O,O′)(thiophen-2-carboxylato-O)manganese(II) monohydrate are bridged by oxygen atoms donated by bidentate carboxylic groups of two thiophen-2-carboxylate ligands. In addition, each Mn(II) ion is coordinated by an oxygen atom of a monodentate carboxylic group of this ligand and three oxygen atoms of water molecules. The coordination around the Mn(II) cation is octahedral. The bridging of the ligands results in molecular ribbons propagating in the c-direction of the crystal held together by C?H…O hydrogen bonds. The crystal structure of diaquobis(μ-furan-3-carboxylato-O,O′)di(μ-furan-3-carboxylato-O,O)(μ-aqua-O)manganese(II) consists of dinuclear structural units. In each molecule Mn(II) cations are O,O′ bridged by oxygen atoms of bidentate carboxylic groups of two furan-3-carboxylate ligands and have a water located between the Mn cations. The units are O,O′ bridged to Mn(II) ions located in adjacent units by bidentate oxygen atoms, forming molecular ribbons extending in the c-direction. Octahedral coordination around each Mn(II) ion is completed by two water molecules. The octahedra around two adjacent metal ions in the unit share a common apex - the bridging oxygen atom of the water molecule. The ribbons are held together by C?H…O hydrogen bonds between furan ring oxygen atoms and the carbon atoms of adjacent furan rings.     

Untersuchung der Komplexierung von Na+, K+, Ca2+ und Ba2+ mit einigen elektrisch neutralen Liganden durch Messung von 13C-chemischen Verschiebungen und Spin-Gitter-Relaxationszeiten

Investigation of the complexing of Na⁺, K⁺, Ca²⁺ and Ba²⁺ with some uncharged ligands by ¹³C-chemical shift and spin-lattice relaxation time measurements The influence of Na⁺, K⁺, Ca²⁺ and Ba²⁺ ions on ¹³C chemical shifts and on spin-lattice relaxation times of some electrically neutral ion carriers was investigated. In the solvents CD₃CN and CD₃OD and in presence of an excess of metal ions ligand 4 (see the Scheme) forms complexes of 1:1 stoichiometry. All four oxygen atoms of the ligand as well as solvent molecules take part in the coordination. In CDCl₃ as solvent, for all ions investigated except sodium, only 1:2 complexes (metal/ligand) were observed with 4 . Sodium ions form both 1:1 and 1:2 complexes in this solvent. In the 1:2 complexes of the investigated monovalent ions only one, in those of the divalent ions both amide carbonyl groups of ligand 4 take part in the coordination.     

Synthesis,characterization and crystal structures of oxidovanadium(V) hydrazone complexes with antibacterial activity

Abstract

Reaction of VO(acac)₂ with the hydrazone ligands N’-(2-hydroxybenzylidene)-3methylbenzohydrazide (H₂L¹) and N’-(2-hydroxybenzylidene)-3-methyl-4-nitrobenzohydrazide (H₂L²) afforded two oxidovanadium(V) complexes, [VOL¹(OMe)(MeOH)] (1) and [VOL²(OEt)(EtOH)] (2), respectively. The complexes have been characterized by elemental analyses, IR, UV-Vis, molar conductivity and X-ray single crystal diffraction techniques. The hydrazone ligands coordinate to the V ions through the phenolate oxygen, imino nitrogen and enolate oxygen atoms. The V ions in both complexes are in octahedral coordination, with the three donor atoms of the hydrazone ligands, and with the other three sites furnished by one methanol or ethanol oxygen atom, one deprotonated methanol or ethanol oxygen atom, and one oxo oxygen. The complexes were assayed for their antibacterial activity on the bacteria B. subtilis, E. coli, P. putida and S. aureus.     

Zinc complexes with 1-(1H-benzimidazol-1-ylmethyl)-1H-benzotriazole: the structure,quantum chemical calculations,and luminescence properties

An organic ligand 1-(1H-benzimidazol-1-ylmethyl)-1H-benzotriazole (bta) and two zinc complexes of the composition [Zn(bta)₂Hal₂] (Hal = Cl, Br) were synthesized. The crystal structure of the complex [Zn(bta)₂Cl₂] was determined and its features were discussed. According to X-ray diffraction data, the central atom has a tetrahedral environment composed of two nitrogen atoms from two ligand molecules coordinated in monodentate mode and two terminal chloride ions. Density functional theory (DFT) calculations of the ligand and complex [Zn(bta)₂Cl₂] were carried out. A study of the luminescence properties of the compounds synthesized suggests that excitation of the zinc complexes gives rise to a dual-band luminescence similar to that of the free ligand. Most probably, the emission originates from π—π* and π—π* intra-ligand transitions.

     

A Tetrahomodioxacalix[6]arene as a Ditopic Ligand for Uranyl Ions with Carbonate or Carbamate Bridges

The first crystal structures of a p-tert-butyltetrahomodioxacalix[6]arene comprising two tri-phenolic subunits separated by two ether bridges and two of its complexes with uranyl ions are reported. The doubly deprotonated macrocycle assumes a much elongated, cone-like conformation including two organic species. Two binuclear uranyl complexes are described. In both, each cation is bound to the three phenoxide oxygen atoms of a tri-phenolic subunit and to a central, bridging, carbonate or carbamate ion. The formation of the latter ions from the amines used as bases is discussed.     

基于5,5′-亚甲基二间苯二甲酸及1,2-双(咪唑基-1-甲基)苯的Zn~(2+)、Co~(2+)配位聚合物的合成及晶体结构

水热条件下,合成了2个三维配位聚合物{[Zn4(L)2(o-bix)2]·2H2O}n(1),{[Co4(L)2(o-bix)2]·2H2O}n(2)(H4L=5,5′-亚甲基二间苯二甲酸,o-bix=1,2-双(咪唑基-1-甲基)苯),并通过红外、热重和X-射线单晶衍射进行了表征。X-射线衍射结果表明这2个化合物具有相似的结构。在1个不对称单元中,化合物包含2个不同配位环境的金属离子,1个L4-配体,1个o-bix分子以及1个游离的溶剂水分子。中心金属离子分别采用畸变的四面体和四方锥构型,形成两类双核单元,然后通过全部脱质子的L4-形成3D孔洞结构,o-bix配体通过连接两类双核金属原子填充于孔洞之中,形成3D紧密堆积结构。对化合物的红外和热重性质进行了表征。     

Synthesis and structural studies of hydrazino-crown ethers and thermodynamic studies of their interaction with transition,and post-transition metal ions and methyl ammonium ion

Hydrazino-crown ethers have been synthesized in only 3 or 4 steps starting from 1,2-diacetylhydrazine. The X-ray crystal structure of protonated hydrazino-19-crown-7 (2) showed that one of the hydrazino nitrogen atoms was directed outside the ring cavity. A solvent methanol molecule is held in the cavity of the host ligand by three hydrogen bonds involving two hydrogen atoms bonded to nitrogens of the ligand and the alcohol hydrogen of the methanol. The logK values for the interaction of2 with CH₃NH ₊ ³ , Ag⁺, Pb²⁺, and Cd²⁺ were much less than those for the interaction of symmetrical triaza-l8-crown-6 (5) with the same cations. Hydrazino-crown2 reduced silver ions to silver metal when a solution of2 and silver ions in DMSO was allowed to stand for several days.     

Structural insight into the anion–water cluster: stabilised by alcohol and carboxylic acid containing tripodal ligand

A new flexible N-bridged, unsymmetrical, water-soluble tripodal ligand (L) bearing alcohol and carboxylic acid groups has been synthesised and its solid-state interaction with anions has been investigated. The fully deprotonated ligand encapsulates a sodium cation in a half cryptand bowl-shaped cavity (1). The chloride complex 2, contains a cyclohexane-like water cluster incorporating ligand OH groups. However, complexes with bromide and nitrate (3 and 4) are dimeric. Tetrahedral clusters containing two water molecules and two anions were found in complexes 3 and 4. Perchlorate complex 5 forms perchlorate–methanol adducts. Complex 1 forms a hydrophilic cation–water channel and complexes 2–4 form anion–water channels between the hydrophobic layers of the naphthalene moieties. Complexes 2, 5 and 3, 4 are isostructural in nature having similar packing structures.     

基于5,5’-亚甲基二间苯二甲酸及1,2-双（咪唑基-1-甲基）-苯的Zn2+、Co2+配位聚合物的合成及晶体结构

水热条件下,合成了2个三维配位聚合物{[Zn₄（L）₂（o-bix）₂]·2H₂O}_n（1）,{[Co₄（L）₂（o-bix）₂]·2H₂O}_n（2）（H₄L=5,5’-亚甲基二间苯二甲酸,o-bix=1,2-双（咪唑基-1-甲基）-苯）,并通过红外、热重和X-射线单晶衍射进行了表征。X-射线衍射结果表明这2个化合物具有相似的结构。在1个不对称单元中,化合物包含2个不同配位环境的金属离子,1个L^4-配体,1个o-bix分子以及1个游离的溶剂水分子。中心金属离子分别采用畸变的四面体和四方锥构型,形成两类双核单元,然后通过全部脱质子的L^4-形成3D孔洞结构,o-bix配体通过连接两类双核金属原子填充于孔洞之中,形成3D紧密堆积结构。对化合物的红外和热重性质进行了表征。     

Synthesis, characterization and biological activities of Cu(II), Co(II), Mn(II), Fe(II), and UO2(VI) complexes with a new Schiff Base hydrazone: O-hydroxyacetophenone-7-chloro-4-quinoline hydrazone

The Schiff base hydrazone ligand HL was prepared by the condensation reaction of 7-chloro-4-quinoline with o-hydroxyacetophenone. The ligand behaves either as monobasic bidentate or dibasic tridentate and contain ONN coordination sites. This was accounted for be the presence in the ligand of a phenolic azomethine and imine groups. It reacts with Cu(II), Ni(II), Co(II), Mn(II), UO(2) (VI) and Fe(II) to form either mono- or binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, NMR, Mass, and UV-Visible spectra. The magnetic moments and electrical conductance of the complexes were also determined. The Co(II), Ni(II) and UO(2) (VI) complexes are mononuclear and coordinated to NO sites of two ligand molecules. The Cu(II) complex has a square-planar geometry distorted towards tetrahedral, the Ni(II) complex is octahedral while the UO(2) (VI) complex has its favoured heptacoordination. The Co(II), Mn(II) complexes and also other Ni(II) and Fe(III) complexes, which were obtained in the presence of Li(OH) as deprotonating agent, are binuclear and coordinated via the NNNO sites of two ligand molecules. All the binuclear complexes have octahedral geometries and their magnetic moments are quite low compared to the calculated value for two metal ions complexes and thus antiferromagnetic interactions between the two adjacent metal ions. The ligand HL and metal complexes were tested against a strain of Gram +ve bacteria (Staphylococcus aureus), Gram -ve bacteria (Escherichia coli), and fungi (Candida albicans). The tested compounds exhibited high antibacterial activities.     

含双水杨醛Schiff碱配体的双核配合物的合成及晶体结构

合成了4个含双水杨醛Schiff碱配体的双核过渡金属配合物,并通过元素分析、红外光谱、紫外光谱,热重分析以及X-射线单晶衍射等手段对所得配合物进行了表征。结果表明,配合物1、3和4都属于三斜晶系,空间群为P1,而配合物2属于单斜晶系,空间群为C2/c。在配合物1中,2个Cu髤离子具有不同的配位构型,其中一个Cu髤形成了五配位的四角锥构型,而另一个Cu髤形成了平面正方形构型。配合物4中,通过酚氧原子的桥联作用,双核单元相互连接形成了一维链状结构。     

The Synthesis and Characterization of Mononuclear and Binuclear Iron(II) Clathrochelate Complexes Derived from 2,3-Butanedione Oxime Hydrazone

The synthesis and characterization of a new series of iron(II) clathrochelate complexes, including the first example of a binuclear covalently linked c1athrochelate complex, is reported. The ligand system is based on the bifunctional chelate 2,3-butanedione oxime hydrazone which forms a tris-complex with iron(II). The c1athrochelate is completed by capping the complex with both a boronic acid/oxime capping reaction and a formaldehyde/hydrazone capping reaction. Electrochemical and spectroscopic characterizations of the complexes are discussed.     

Hydrothermal synthesis and characterizations of a novel modular europium(III) coordination polymer bridged by biphenyl-2,2′-dicarboxylate dianions and 1,10-phenanthroline

A novel europium(III) coordination polymer, [Eu₂(bpdc)₃(phen)₂(H₂O)₂] _n ·nH₂O (1) (bpdc?= biphenyl-2,2′-dicarboxylate; phen?=?1,10-phenanthroline), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction methods. Complex 1 is monoclinic, space group C2/c, with a?=?24.3862(6), b?=?12.0792(3), c?=?22.9120(5)?Å, α?=?90.00, β?=?115.160(1), γ?=?90.00°, V?=?6108.8(3)?ų, Z?=?4, final R ₁?=?0.0605 and wR ₂?=?0.1760. Each Eu(III) ion is coordinated by six oxygen atoms from three carboxylate groups of three different bpdc anions, an oxygen atom from one coordinated water molecule and two nitrogen atoms from one phen ligand to complete a deformed monocapped square antiprism. Each pair of bpdc anions acts as a tetradentate ligand to connect two adjacent Eu(III) ions through chelating carboxylate groups, resulting in a centrosymmetric binuclear unit. Each binuclear unit links two adjacent binuclear units through two terminal bpdc anions to produce a one-directional zigzag chain. Two different kinds of hydrogen-bonding interactions link the chains and the lattice water molecules to form a hydrogen-bonding network.     

Proton Controlled Supramolecular Assembly: A Comparative Structural Study of Bis(2-guanidinobenzimidazolo)nickel(II) with Bis(2-guanidinobenzimidazole)nickel(II) Nitrate and 2-guanidinobenzimidazole

Abstract

Previously studies have shown that when 2-guanidinobenzimidazole complexes with a number of transition metal ions it tautomerises so that, in contrast to the free ligand structure, no intermolecular hydrogen bonding between bound ligands occurs. In the present study it is demonstrated that ligand deprotonation to yield bis(2-guanidinobenzimidazolo)nickel(II) restores much of the original hydrogen bonding capability of the uncomplexed ligand. The structure of this neutral complex is compared to the previously reported structure of its diprotonated derivative, bis(2-guanidinobenzimidazole)nickel(II) nitrate, as well as to the structure of the uncomplexed ligand. In contrast to the dicationic species, the neutral complex exists in two enantiomeric forms that assemble to form an extended supramolecular lattice, containing channels through its structure. The walls of the channels are made up of ‘strings’ of complex molecules and are held in position by hydrogen bonding between the bound ligands and dimethyl sulfoxide (solvent) molecules as well as water molecules. Some of the solvent molecules lie within the channels and some outside. The hydrogen bonding motif responsible for chain formation differs from that found in the free ligand structure.     

Synthesis,crystal structures and antimicrobial activity of azido and isocyanato Zn(II) complexes with the condensation product of 2-quinolinecarboxaldehyde and Girard’s T reagent

Two Zn(II) complexes with the condensation product of 2-quinolinecarboxaldehyde and trimethylammonium acetohydrazide chloride (Girard’s T reagent) (HLCl) and monodentate pseudohalides (azide and cyanate) have been synthesized and characterized by elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction. In both complexes, the coordination surroundings of the Zn(II) ions consist of a deprotonated hydrazone ligand coordinated through an NNO set of donor atoms and two monodentate pseudohalides (N₃^– or NCO^–) at the remaining coordination sites. The Zn(II) complexes showed low to moderate activity against laboratory control strains of pathogenic bacteria and fungi.     

Synthesis and crystal structures of new sodium phenolate compounds: coordination chemistry

Four new sodium complexes of phenolate and bisphenolate ligands have been synthesized and characterized by NMR spectroscopy and X-ray crystallography to study their coordination chemistry. The monoanionic tridentate [ONN] phenolate ligand gave a dimeric compound [Na₂L₂] (2), which crystallized in the orthorhombic crystal system, where the sodium ions have four coordination environments. The dianionic tridentate [ONO] phenolate ligand gave a dimeric [Na₂(L^IH)₂] (4) compound in the tetragonal crystal system. The sodium ions Na(1) and Na(1?) are four-coordinate both having a tetrahedral geometry with the O–Na–O angle being ca. 93°, the O^N^O ligand string comprising a tridentate ligand. Interestingly, despite the steric bulk of N(SiMe₃)₂, a mixture of compounds [NaL] (2) and NaN(SiMe₃)₂ was isolated as a dimeric structure [Na₂L(N(SiMe₃)₂)]₂ (5) crystallized in the monoclinic crystal system. Na(1) is four-coordinate bonding to the phenolic oxygen atom and two N atoms of the ligand L and the N of the N(SiMe₃)₂ ligand. The coordination around Na(1) is tetrahedrally distorted square planar with the ‘cis’ angles ranging from 75.11(4) to 117.40(5)° and the ‘trans’ angles being 140.87(4) and 154.82(5)°. Na(2) is three-coordinate, bonding to the two phenolate oxygen atoms and the N atom of the N(SiMe₃)₂ ligand. Na(2), however, is not coplanar with these atoms being displaced 0.42 Å from it. The coordination chemistry for 5 is very intriguing as the sodium ions have mixed four- and three-coordination numbers, probably due to the steric hindrance of the silylamide groups.