Synthesis and characterization of Cu(II), Co(II) and Ni(II) coordination polymers containing bis(imidazolyl) ligands

Two structurally related flexible imidazolyl ligands, bis(N-imidazolyl)methane (L₁) and 1,4-bis(N-imidazolyl)butane (L₂), were reacted with Cu(II), Co(II) and Ni(II) salts of aliphatic/aromatic dicarboxylic acids resulting in the formation of a number of novel metal–organic coordination architectures, [CuB₂(ox)₂(L₁)₂(H₂O)₂] · 4H₂O (1) (ox = oxalate), [Cu(pdc)(L₂)_1.5] · 4H₂O (2, pdc = pyridine-2,6-dicarboxylate), [Co(L)₂(H₂O)₂](tp) · 4H₂O (3, tp = terephthalate), [Ni(L₁)₂(H₂O)₂](ip) · 5H₂O (4, ip = isophthalate), [Cu₂(L₁)₄(H₂O)₄](tp)₂ · 7H₂O (5), [Co(mal)(L₁)(H₂O)] · 0.5MeOH (6, mal = malonate), [Co(pdc)(L₁)(H₂O)] (7). All the complexes have been structurally characterized by X-ray diffraction analysis. The different coordination modes of the dicarboxylate anions, due to their chain length, rigidity and diimidazolyl functionality, lead to a wide range of different coordination structures. The coordination polymers exhibit 1D single chain, ladder, 2D sheet and 2D network structures. The aliphatic and aromatic dicarboxylates can adopt chelating μ₂ and chelating-bridging μ₃ coordination modes, or act as uncoordinated counter anions. The central metal ions are coordinated in N₂O₄, N₄O₂, N₂O₃ and N₃O₃ fashions, depending on the ancillary ligands. The topology of 1 gives rise to macrocycles which are connected through hydrogen bonds to form 1D chains, whereas compound 2 exhibits a 1D polymeric ladder in which the carboxylate acts as a pincer ligand. Compounds 3–5 show doubly bridged 1D chains, and the dicarboxylate groups are not coordinated but form 2D corrugated sheets with water molecules intercalated between the cationic layers. Compound 6 has a 2D network sheet structure in which each metal ion links three neighboring Co atoms by the bis(N-imidazolyl)methane ligand. The cobalt compound 7, with a 2D polymeric double sheet structure, is built from pincer carboxylate (pdc) and 1,4-bis(N-imidazolyl)methane ligands.     

Three 2D mixed-ligand Co(II) coordination polymers containing flexible bis(benzimidazole) ligands with different spacers

Three new Co(II) coordination polymers, [Co(L1)(bpdc)] _n (1), [Co(L2)(ndc)(H₂O)·2H₂O] _n (2) and [Co(L3)(ndc)(H₂O)·H₂O] _n (3) (L1 = 1,2-bis(5,6-dimethylbenzimidazole)ethane, L2 = 1,3-bis(5,6-dimethylbenzimidazole)propane, L3 = 1,4-bis(5,6-dimethylbenzimidazole)butane, H₂bpdc = 4,4′-biphenyldicarboxylic acid, H₂ndc = 2,6-naphthalenedicarboxylic acid) have been synthesized under hydrothermal conditions and structurally characterized by X-ray crystallography. All three complexes feature (4,4) networks that extend into 3D supramolecular frameworks via hydrogen bonding interactions. The luminescence properties and catalytic activities of these complexes with respect to the degradation of methyl orange in a Fenton-like process have been investigated.     

Novel Pb(II), Zn(II), and Cd(II) coordination polymers constructed from ferrocenyl-substituted carboxylate and bipyridine-based ligands

Treatment of two kinds of ferrocenyl-substituted carboxylate ligands (3-ferrocenyl-2-crotonic acid, HOOC-CH=(CH(3))CFc (Fc=(eta(5)-C(5)H(5))Fe(eta(5)-C(5)H(4))) or O-ferrocecarbonyl benzoic acid, o-HOOCC(6)H(4)COFc with Pb(OAc)(2).3H(2)O, Zn(OAc)(2).2H(2)O, or Cd(OAc)(2).2H(2)O) resulted in four novel ferrocene-containing coordination polymers [[Pb(mu(2)-eta(2)-OOCCH=(CH(3))CFc)(2)].MeOH](n) (1), [[Zn(o-OOCC(6)H(4)COFc)(2)(4,4'-bipy)(H(2)O)(2)].2MeOH.2H(2)O](n) (4,4'-bipy = 4,4'-bipyridine) (2), [[Cd(o-OOCC(6)H(4)COFc)(2)(bpe)(MeOH)(2)].2H(2)O](n) (bpe = 1,2-bis(4-pyridyl)ethene) (3), and [Pb(o-OOCC(6)H(4)COFc)(eta(2)-o-OOCC(6)H(4)COFc)(bpe)](n)() (4). Their crystal structures have been characterized by single X-ray determinations. In polymer 1, Pb(II) ions are bridged by tridentate FcC(CH(3))=CHCOO(-) anions, forming an infinite chain [Pb(mu(2)-eta(2)-OOC=CH(CH(3))CFc)(2)](n). In polymers 2-4, there are three kinds of components, metal ions, o-FcCOC(6)H(4)COO(-) units, and organic bridging ligands. The bipyridine-based ligands connect metal ions leading to a one-dimensional chain with o-FcCOC(6)H(4)COO(-) units acting as monodentate or chelate ligands in the side chain. Such coordination polymers containing ferrocenyl-substituted carboxylate and bipyridine-based ligands are very rare. The solution-state differential pulse voltammetries of polymers 1-4 were determined. The results indicate that the half-wave potential of the ferrocenyl moieties is influenced by the Pb(II) ions in polymer 1 and strongly influenced by Zn(II), Cd(II), or Pb(II) ions in polymers 2-4. The thermal properties of the four polymers were also investigated.     

One-dimensional coordination polymers of Co(II) and Cd(II)-squarate with 2-methylimidazole and 4(5)-methylimidazole ligands

Two new mixed-ligand coordination polymers, {[Co(μ_1,3-sq)(H₂O)₂(2-Meim)₂]·2(2-Meim)}_n (1) and [Cd(μ_1,3-sq)(H₂O)₂(4(5)-Meim)₂]_n (2), (sq = squarate, 2-Meim = 2-methylimidazole, 4(5)-Meim = 5-methylimidazole) have been synthesized and structurally characterized by X-ray crystallography. The spectral (IR and UV–Vis) and thermal analyses are also reported. The Co(II) and Cd(II) ions are distorted octahedrally coordinated by four oxygen atoms of two O¹–O³-bridging squarate ligands and two trans-aqua ligands, and by two nitrogen atoms of the trans-imidazole (2-Meim or 4(5)-Meim) ligands. The structures of 1 and 2 consist of one-dimensional chains of μ-1,3-squarato bridged metal(II) complex units. These chains are held together by hydrogen bonding interactions, forming three-dimensional framework.     

Homochiral Zn and Cd coordination polymers containing amino acid-tetrazole ligands

The reactions of (S)-3-cyanophenylalanine with NaN(3) in the presence of H(2)O and Lewis acids (ZnCl(2) and CdCl(2)) afford two unprecedented 3D homochiral networks, mono[(S)-5-(3-tetrazoyl)-phenylalaninato]zinc(II) (1) and mono[(S)-5-(3-tetrazoyl)-phenylalaninato]cadmium(II) monoaqua(II) (2), respectively. The two compounds are isostructural with noninterpenetrated SrAl(2) topology. The structure of these coordination polymers gives new insight into Sharpless' reaction of chiral 5-substituted 1H-tetrazole and homochiral supramolecular array constructions.     

Synthesis and structural characterization of 2D Zn(II), Cd(II), and Co(II) coordination polymers containing 3-chloro-1,2-benzenedicarboxylate and positional isomers of triazole-bipyridine

Three compounds, [Zn₂L₂(4,4′-bpt)₂] _n (1), [Cd₂L₂(3,4′-bpt)(H₂O)₂] _n (2) and {[CoL(3,3′-bpt)(H₂O)]?H₂O} _n (3) (L?=?3-Cl-1,2-benzenedicarboxylate dianion, 4,4′-bpt?=?1H-3,5-bs(4-pyridyl)-1,2,4-itriazole, 3,4′-bpt?=?1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole and 3,3′-bpt?=?1H-3,5-bis(3-pyridyl)-1,2,4-triazole), based on three positionally isomeric triazole-bipyridine ligands, were synthesized. Structural analyses of 1–3 reveal diverse 2-D network structures, which are based on different [ML] _n (M?=?Zn, Cd, Co) chains. In the [ZnL] _n chains of 1, the carboxylic groups of L connect the adjacent Zn(II) centers with a monodentate bridging coordination mode (μ₂-η^{1 ?}/^? η¹ ). In 2, [CdL] _n is a double chain connected by the carboxylic groups of L with μ₃-η^{1 ?}/^? η²/η² and μ₃-η^{1 ?}/^? η^{1 ?}/^? η² bridges. The [CoL] _n chains of 3 are formed by the carboxylic groups of L with the μ₂-η^{1 ?}/^? η² coordination mode. The powder X-ray diffraction and the thermal stability of 1–3, the luminescent properties of 1 and 2, and the magnetic behavior of 3 have been briefly investigated.     

Physico-chemical studies of Ni(II), Co(II), Zn(II) and Cd(II) ions-p-bromobenzoylacetonate systems

The thermodynamic dissociation constant (pk_D) of p-bromobenzoylacetone and overall stability constants (log β₂) of its complexes with Ni(II), Co(II), Zn(II) and Cd(II) have been determined potentiometrically in dioxane-water mixture (75%, v/v) at 30±0·1°C in 0·1 M sodium perchlorate. On incorporating pH corrections, the pk_D of the ligand became 11·76±0·02. The thermodynamic values of log β₂ have been evaluated using correction-term method, linear plot and method of least squares. The values of log β₂ obtained from the latter method turned out to be 18·64±0·03, 17·94±0·04, 17·53±0·03 and 14·75±0·03 for Ni(II), Co(II), Zn(II) and Cd(II) complexes, respectively. This order is consistent with the Irving-William's series.The solid bis(p-bromobenzoylacetonate) dihydrate complexes of these metals have been synthesised and characterised.     

Zn(II) and Cd(II) coordination polymers assembled by di(1H-imidazol-1-yl)methane and carboxylic acid ligands

Five new Zn(II)/Cd(II) coordination polymers constructed from di(1H-imidazol-1-yl)methane (L) mixed with different auxiliary carboxylic acid ligands formulated as [Zn(L)(H(2)L(1))(2)·(H(2)O)(0.2)](n) (1), {[Zn(L)(L(2))]·H(2)O}(n) (2), {[Cd(2)(L)(2)(L(2))(2)]·2H(2)O}(n) (3), {[Cd(L)(L(3))]·H(2)O}(n) (4) and [Cd(L)(L(4))](n) (5) (H(3)L(1) = 1,3,5-benzenetricarboxylic acid, H(2)L(2) = 4,4'-oxybis(benzoic acid), H(2)L(3) = m-phthalic acid and H(2)L(4) = p-phthalic acid) have been synthesized under hydrothermal conditions and structurally characterized. Four related auxiliary carboxylic acids were chosen to examine the influences on the construction of these coordination frameworks with distinct dimensionality and connectivity. The coordination arrays of 1-5 vary from 1D zigzag chain for 1, 2D (4,4) layer for 2-4, to 2-fold interpenetrated 3D coordination network with the α-Po topology for 5. The thermal and photoluminescence properties of complexes 1-5 in the solid state have also been investigated.     

Novel coordination compounds: Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) cations with acesulfame/N,N-diethylnicotinamide ligands

Abstract

Five coordination complexes with Mn²⁺ (1), Co²⁺ (2), Ni²⁺ (3), Cu²⁺ (4), and Zn²⁺ (5) containing acesulfame (ace) and N,N-diethylnicotinamide (dena) ligands were synthesized and structural binding properties investigated. Four compounds (1, 2, 4, and 5) were examined with single crystal X-ray diffraction methods. The structures containing Mn(II), Co(II), and Zn(II) were iso-structural. Six-coordination of metal cations were completed with two moles dena and four aqua ligands. The dena ligands were coordinated via pyridine nitrogen as neutral-monodentate. Charge stabilities of the complexes are complemented by two moles monoanionic ace ligands, located outside of the coordination unit. In the Cu(II) complex, the coordination is completed by acidic nitrogen and carbonyl oxygen atoms of two ace ligands and pyridine nitrogen of two moles dena ligands. The coordination to Cu(II) for ace ligands was monoanionic-bidentate. All metal cations in the structure are distorted octahedral. Thermal decomposition of complexes begins with removal of the aqua molecules from the structures and is completed by combustion of organic ligands. The final decomposition products of all structures have been identified as corresponding metal oxides. Some biological applications (anti-fungal/anti-bacterial) were studied using 1–5.     

Physico-chemical studies of Ni(II), Co(II), Zn(II), and Cd(II) ions with p-fluorobenzoylacetone

Incorporation of pH correction, in data obtained from the potentiometric titration of p-fluorobenzoylacetone with NaOH solution in dioxane-water (31,V/V) at 30±0.1°C in a medium of constant ionic strength, =0.1M (NaClO₄) gave the value of thermodynamic dissociation constant (pk _D ) as 12.06±0.02. Under similar conditions of solvent composition, temperature and ionic strength the thermodynamic stepwise formation constants of the complexes formed between Ni(II), Co(II), Zn(II) and Cd(II) ions and the above ligand, using method of least squares, gave log ₂ as 19.50±0.05, 18.89±0.05, 18.61±0.04 and 16.16±0.08 resp. This order is in accordance with theIrving-Williams series. Derivatives of the above metals have also been synthesised and characterised.With 2 Figures     

Dinuclear tetrapyridyl pendant-armed azamacrocyclic complexes of Co(II), Ni(II), Cu(II) and Cd(II)

The coordination capability of the new tetrapyridyl pendant-armed azamacrocyclic ligand L, towards Co(II), Ni(II), Cu(II) and Cd(II) ions was studied. The ligand and the complexes were characterized by microanalysis, LSI mass spectrometry, IR, UV-Vis and NMR spectroscopy, magnetic studies and conductivity measurements. Crystal structures of [Co₂L(CH₃CN)₂](ClO₄)₄·2CH₃CN and [Cd₂L(NO₃)₂](NO₃)₂·2H₂O complexes have been determined. The X-ray studies show the presence of dinuclear endomacrocyclic complexes with the metal ion in a similar distorted octahedral environment, coordinated by one pyridyl bridgehead group, two amine nitrogen atoms and two pyridyl pendant-arms. The sixth coordination position around the metal ion is completed by one acetonitrile molecule in [Co₂L(CH₃CN)₂](ClO₄)₄·2CH₃CN and by one monodentate nitrate anion in [Cd₂L(NO₃)₂](NO₃)₂·2H₂O. Different sort of intramolecular non-classical hydrogen bonds were found in the crystal lattice of both structures.     

Orotic acid complexes of Co(II), Ni(II), Zn(II) and Cd(II) with imidazole

The [Co(HOr)(H₂O)₂(im)₂] (1), [Ni(HOr)(H₂O)₂(im)₂] (2), [Zn(H₂O)₂(im)₄](H₂Or)₂ (3) and [Cd(HOr)(H₂O)(im)₃] (4) complexes (H₃Or: orotic acid, im: imidazole) were synthesized and characterized by elemental analysis, magnetic and conductance measurements, UV-vis and IR spectra. The thermal behaviour of the complexes was also studied by simultaneous thermal analysis techniques (TG, DTG and DTA). The orotate ligand (HOr²⁻) coordinated to the Co(II), Ni(II) and Cd(II) ions are chelated to the deprotonated pyrimidine nitrogen (N₍₃₎) and the carboxylate oxygen, while do not coordinate to the Zn(II) ion is present as a counter-ion (H₂Or⁻). The first thermal decomposition process of all the complexes is endothermic deaquation. This stage is followed by partially (or completely) decomposition of the imidazole and orotate ligands. In the later stage, the remained organic residue exothermically burns. On the basis of the first DTG_max, the thermal stability of the complexes follows order: 2, 176°C>1, 162°C>4, 155°C>3, 117°C in static air atmosphere. The final decomposition products which identified by IR spectroscopy were the corresponding metal oxides.     

Studies of Co(II), Ni(II), Cu(II) and Cd(II) chelates with different phosphonic acids

Co(II), Ni(II), Cu(II) and Cd(II) chelates with 1-aminoethylidenediphosphonic acid (AEDP, H₄L¹), α-amino benzylidene diphosphonic acid (ABDP, H₄L²), 1-amino-2-carboxyethane-1,1-diphosphonic acid (ACEDP, H₅L³), 1,3-diaminopropane-1,1,3,3-tetraphosphonicacid (DAPTP, H₈L⁴), ethylenediamine-N,N′-bis(dimethylmethylene phosphonic)acid (EDBDMPO, H₄L⁵), O-phenylenediamine-N,N′-bis(dimethyl methylene phosphonic)acid (PDBDMPO, H₄L⁶), diethylene triamine-N,N,N′,N′,N″N″-penta(methylene phosphonic)acid (DETAPMPO, H₁₀L⁷) and diethylene triamine-N,N″-bis(dimethyl methylene phosphonic)acid (DETBDMPO, H₄L⁸) have been synthesised and were characterised by elemental and thermal analyses as well as by IR, UV–VIS, EPR and magnetic measurements. The first stage in the thermal decomposition process of these complexes shows the presence of water of hydration, the second denotes the removal of the coordinated water molecules. After the loss of water molecules, the organic part starts decomposing. The final decomposition product has been found to be the respective MO·P₂O₅. The data of the investigated complexes suggest octahedral geometry with respect to Co(II) and Ni(II) and tetragonally distorted octahedral geometry with respect to Cu(II). Antiferromagnetism has been inferred from magnetic moment data. Infrared spectral studies have been carried out to determine coordination sites.     

Formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates

A study is reported of the formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates. The results show that the precipitates form by reaction of the metal ions with KCo(CN)(6)(2-) ion-pairs in 1:1 ratio, followed by solid phase transformations.     

The coordination behaviour of ferrocene-based pyridylphosphine ligands towards Zn(II), Cd(II) and Hg(II)

The reaction of Group 12 metal dihalides MX(2) with the P,N-ligands [Fe(C(5)H(4)-PPh(2))(C(5)H(4)-2-py)] (1) (2-py = pyrid-2-yl), [Fe(C(5)H(4)-PPh(2))(C(5)H(4)-CH(2)-2-py)] (2) and [Fe(C(5)H(4)-PPh(2))(C(5)H(4)-3-py)] (3) (3-py = pyrid-3-yl) was investigated. For a 1 : 1 molar ratio of MX(2) and the respective ligand, three structure types were found in the solid state, viz. chelate, cyclic dimer and chain-like coordination polymer. The M(II) coordination environment is distorted pseudo-tetrahedral in each case. The P-M-N angle is much larger in the chelates (≥119°) than in the ligand-bridged structures (≤109°). 1 prefers the formation of chelates [MX(2)(1-κ(2)N,P)]. 3 forms coordination polymers [MX(2)(μ-3)](n). With the more flexible 2 all three structure types can occur. Dynamic coordination equilibria were observed in solution for the molecular complexes obtained with 1 and 2. NMR data indicate that the N- and P-donor sites interact most strongly with Zn(II) and Hg(II), respectively. While the formation of bis(phosphine)mercury complexes (soft-soft) was easily achieved, no bis(pyridine)zinc complex (borderline-borderline) could be obtained, which is surprising in view of the HSAB principle.     

由不同长度柔性双咪唑配体构筑的镍(Ⅱ)配位聚合物（英文）

利用2,5-吡啶二酸分别与两种具有不同长度的柔性双咪唑配体,在同样的水热条件下合成了两例结构完全不同的镍(Ⅱ)配位聚合物Ni2(2,5-pdc)_2(L1)_2(H_2O)_2·6H2O(1),Ni(2,5-pdc)(L_2)(H_2O)·H_2O[2,5-pdc=2,5-吡啶二酸,L1=1,4-二(1-咪唑基)丁烷,L2=1,6-二(1-咪唑基)己烷](2).配合物1是三维4-连CdSO_4拓扑网格,Schlfli符号为(6~5·8).而配合物2是由一维螺旋链[Ni(L_2)]n和一维[Ni(2,5-pdc)]n链构筑而成的环-环相扣的一维链状结构.     

Synthesis,characterization, and crystal structures of 2D cobalt(II) and nickel(II) coordination polymers containing flexible bis(benzimidazole) ligands

Three coordination polymers, namely {[Ni(L1)(nip)(H₂O)]·2H₂O} _n (1), [Co(L2)(tbip)] _n (2), and {[Co₂(L3)₂(bptc)]·3H₂O} _n (3) (L1 = 1,4-bis(5,6-dimethylbenzimidazole)butane, L2 = 1,4-bis(5,6-dimethylbenzimidazole)-2-butylene, L3 = 1,3-bis(5,6-dimethylbenzimidazole)propane, H₂nip = 5-nitro-isophthalic acid, H₂tbip = 5-tert-butyl-isophthalic acid, H₄bptc = biphenyl-3,3′,4,4′-tetracarboxylic acid), have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as by single-crystal X-ray diffraction analysis. Complexes 1 and 2 both feature a two-dimensional (4,4) layer with (4⁴ × 6²) topology. Complex 3 possesses a uninodal 4-connected 2D htb network. The fluorescence spectra and catalytic properties of the complexes for the degradation of methyl orange by sodium persulfate in a Fenton-like process are reported.     

Solid-state thermal degradation behaviour of 1-D coordination polymers of Ni(II) and Cu(II) bridged by conjugated ligand

Monometallic complexes [Cudadb·yH₂O]_n (2) and [Nidadb·yH₂O]_n (3) and heterobimetallic complex [Cu_0.5Ni_0.5dadb·yH₂O]_n (4) {where dadbH₂ = 2,5-Diamino-3,6-dichloro-1,4-benzoquinone (1); y = 2–4; n = degree of polymerization} were characterized by elemental analysis, atomic absorption spectroscopy, infrared spectroscopy (FTIR) and powder X-ray diffraction. The thermal behaviour of the complexes was studied by thermal analysis (TG/DTA) under air as well as under helium atmospheres. The released gaseous products were investigated by evolved gas analysis performed by an online coupled mass spectrometer (TG/DTA-MS). Thermal degradation of 2 under helium atmosphere is distributed over five steps, whereas 3 and 4 exhibited only four degradation steps due to overlap of second and third degradation steps of into one major step. All the complexes exhibit three steps degradation under air. The complex 2 loses NH group in the second and HCl/Cl₂, CO groups simultaneously in third steps of decomposition under helium, whereas it loses NH and CO groups simultaneously in low temperature region of second step of degradation under air atmosphere as the loss of CO group is facilitated by air. EGA-MS under air and helium atmospheres shows that HCl, CO/CO₂ and (CN)₂ fragments are lost simultaneously at multiple steps, and not successively as predicted earlier. Rate of evolution of most evolved gases exhibits several maxima as a consequence of degradation followed by recombination reactions. Final residues under air and helium atmospheres correspond to the metal oxides and metals along with some carbonaceous matter.     

New Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with 3,3-dimethylglutaric Acid

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)3,3-dimethylglutarates were investigated and their quantitative composition, solubility in water at 293 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with general formula MC₇H₁₀O₄⋅nH₂O (n=0−2) were recorded and their thermal decomposition in air were studied. During heating the hydrated complexes of Mn(II),Co(II), Ni(II) and Cu(II) are dehydrated in one step and next all the anhydrous complexes decompose to oxides directly (Mn, Co, Zn) or with intermediate formation free metal (Ni,Cu) or oxocarbonates (Cd). The carboxylate groups in the complexes studied are bidentate. The magnetic moments for the paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II)attain values 5.62, 5.25, 2.91 and 1.41 M.B., respectively. This revised version was published online in August 2006 with corrections to the Cover Date.