A cadmium(II) coordination polymer with both polyrotaxane and polycatenane features constructed by a V‐shaped semi‐rigid ligand: synthesis and fluorescence properties

One of the most interesting phenomena in coordination polymers (CPs) is the co‐existence of different interlaced motifs. However, CPs having two different interlaced motifs at the same time are still rare. Colourless block‐shaped crystals of the two‐dimensional polymer poly[[aqua(μ₂‐naphthalene‐2,6‐dicarboxylato){μ₂‐4,4′‐[oxybis(4,1‐phenylene)]dipyridine}cadmium(II)] monohydrate], {[Cd(C₁₂H₆O₄)(C₂₂H₁₆N₂O)(H₂O)]·H₂O}_n , (I), was synthesized under hydrothermal conditions by the self‐assembly of 4,4′‐[oxybis(4,1‐phenylene)]dipyridine (OPY) with Cd^II in the presence of naphthalene‐2,6‐dicarboxylic acid (H₂ndc). Each Cd^II ion is six‐coordinated by two N atoms from the pyridine rings of two OPY ligands and by four O atoms, three of which are from two ndc²⁻ ligands and one of which is from a water molecule. In (I), every two identical two‐dimensional (2D) 6³ layers are interpenetrated in a parallel fashion, resulting in an interesting 2D→2D framework with both polyrotaxane and polycatenane characteristics. The extension of these sheets into a three‐dimensional supramolecular net is via O—H…O hydrogen bonds. The solid‐state photoluminescence properties of (I) are also discussed.     

Syntheses and characterization of dinuclear and tetranuclear AgI supramolecular complexes generated from symmetric and asymmetric molecular clips containing oxadiazole rings

A new asymmetric ligand, 5‐{3‐[5‐(4‐methylphenyl)‐1,3,4‐oxadiazol‐2‐yl]phenyl}‐2‐(pyridin‐3‐yl)‐1,3,4‐oxadiazole ( L5 ), which contains two oxadiazole rings, was synthesized and characterized. The assembly of symmetric 2,5‐bis(pyridin‐3‐yl)‐1,3,4‐oxadiazole ( L1 ) and asymmetric L5 with AgCO₂CF₃ in solution yielded two novel Ag^I complexes, namely catena‐poly[[di‐μ‐trifluoroacetato‐disilver(I)]‐bis[μ‐2,5‐bis(pyridin‐3‐yl)‐1,3,4‐oxadiazole]], [Ag₂(C₂F₃O₂)₂(C₁₂H₈N₄O)₂]_n or [Ag₂(μ₂‐O₂CCF₃)₂( L1 )₂]_n ( 1 ), and bis(μ₃‐5‐{3‐[5‐(4‐methylphenyl)‐1,3,4‐oxadiazol‐2‐yl]phenyl}‐2‐(pyridin‐3‐yl)‐1,3,4‐oxadiazole)tetra‐μ₃‐trifluoroacetato‐tetrasilver(I) dichloromethane monosolvate, [Ag₄(C₂F₃O₂)₄(C₂₂H₁₅N₅O₂)₂]·CH₂Cl₂ or [Ag₂(μ₃‐O₂CCF₃)₂( L5 )]₂·CH₂Cl₂ ( 2 ). Complex 1 displays a one‐dimensional ring–chain motif, where dinuclear Ag₂(CF₃CO₂)₂ units alternate with Ag₂( L1 )₂ macrocycles. This structure is different from previously reported Ag– L1 complexes with different anions. Complex 2 features a tetranuclear supramolecular macrocycle, in which each ligand adopts a tridentate coordination mode with the oxadiazole ring next to the p‐tolyl ring coordinated and that next to the pyridyl ring free. Two L5 ligands are bound to two Ag1 centres through two oxadiazole N and two pyridyl N atoms to form a macrocycle. The other two oxadiazole N atoms coordinate to the two Ag2 centres of the Ag₂(O₂CCF₃)₄ dimer. Each CF₃CO₂^? anion adopts a μ₃‐coordination mode, bridging the Ag1 and Ag2 centres to form a tetranuclear silver(I) complex. This study indicates that the donor ability of the bridging oxadiazole rings can be tuned by electron‐withdrawing and ‐donating substituents. The emission properties of ligands L1 and L5 and complexes 1 and 2 were also investigated in the solid state.     

Synthesis and Crystal Structure of a New 2D Honeycomb—like Cadmium （Ⅱ） Complex with Tripodal Ligand

A new cadmium (II) coordination polymer, [Cd(TTTMB)₂]‐(SO₄) · 21H₂O, where TTTMB =1,3, 5‐tris (imidazol‐1‐yl‐methyl)‐2,4,6‐trimethylbenzene, was obtained by self‐assembly of tripodal ligand TTTMB with CdSO₄·2.7H₂O in acetonitrile, and characterized by X‐ray crystallography. The crystal data belongs to monoclinic space group C_c with cell parameters a = 1.16891(4) nm, b=2.06671(6) nm, c = 2.48185(7) nm, β = 97.8560(10)°, R = 0.0487, wR = 0.1211. The results of structure analysis indicate that each TTTMB ligand coordinates three metal atoms and in turn each Cd(II) atom with octahedral coordination geometry connects six nitrogen atoms of imidazole group from six different TTTMB ligands to produce a 2D honeycomb network structure. There are a lot of water molecules linked by hydrogen bonds and occupied the channels formed intra‐ and inter‐sheets.     

Mixed‐ligand MnII and CuII complexes with alternating 2,2′‐bipyrimidine and terephthalate bridges

The novel polymeric complexes catena‐poly[[diaquamanganese(II)]‐μ‐2,2′‐bipyrimidine‐κ⁴N¹,N^1′:N³,N^3′‐[diaquamanganese(II)]‐bis(μ‐terephthalato‐κ²O¹:O⁴)], [Mn₂(C₈H₄O₄)₂(C₈H₆N₄)(H₂O)₄]_n, (I), and catena‐poly[[[aquacopper(II)]‐μ‐aqua‐μ‐hydroxido‐μ‐terephthalato‐κ²O¹:O^1′‐copper(II)‐μ‐aqua‐μ‐hydroxido‐μ‐terephthalato‐κ²O¹:O^1′‐[aquacopper(II)]‐μ‐2,2′‐bipyrimidine‐κ⁴N¹,N^1′:N³,N^3′] tetrahydrate], {[Cu₃(C₈H₄O₄)₂(OH)₂(C₈H₆N₄)(H₂O)₄]·4H₂O}_n, (II), containing bridging 2,2′‐bipyrimidine (bpym) ligands coordinated as bis‐chelates, have been prepared via a ligand‐exchange reaction. In both cases, quite unusual coordination modes of the terephthalate (tpht²⁻) anions were found. In (I), two tpht²⁻ anions acting as bis‐monodentate ligands bridge the Mn^II centres in a parallel fashion. In (II), the tpht²⁻ anions act as endo‐bridges and connect two Cu^II centres in combination with additional aqua and hydroxide bridges. In this way, the binuclear [Mn₂(tpht)₂(bpym)(H₂O)₄] entity in (I) and the trinuclear [Cu₃(tpht)₂(OH)₂(bpym)(H₂O)₄]·4H₂O coordination entity in (II) build up one‐dimensional polymeric chains along the b axis. In (I), the Mn^II cation lies on a twofold axis, whereas the four central C atoms of the bpym ligand are located on a mirror plane. In (II), the central Cu^II cation is also on a special position (site symmetry ). In the crystal structures, the packing of the chains is further strengthened by a system of hydrogen bonds [in both (I) and (II)] and weak face‐to‐face π–π interactions [in (I)], forming three‐dimensional metal–organic frameworks. The Mn^II cation in (I) has a trigonally deformed octahedral geometry, whereas the Cu^II cations in (II) are in distorted octahedral environments. The Cu^II polyhedra are inclined relative to each other and share common edges.     

Mono‐ and tetranuclear copper(I) complexes with N‐heterocyclic chelating and triphenylphosphine ligands: Crystal structures,luminescent and heterogeneous catalytic properties

N‐heterocyclic chelating and triphenylphosphine ligands react with cuprous halide to form a variety of copper(I) complexes, namely, mononuclear [Cu(PBO)(PPh₃)Br]^.CH₂Cl₂ ( 1 ) and [Cu(PBM)(PPh₃)I] ( 2 ) (PBO = 2‐(2′‐Pyridyl)benzoxazole, PBM = 2‐(2′‐Pyridyl)benzimidazole, PPh₃ = triphenylphosphine) and tetranuclear [Cu₄(μ₂‐I)₂(μ₃‐I)₂(PPh₃)₄]^.2CH₂Cl₂ ( 3 ) have been synthesized and characterized. Complexes 1 and 2 are basically alike; both of them are mononuclear and four‐coordinated, possessing a slightly distorted trigonal pyramidal geometry. Complex 3 is tetranuclear and the coordination numbers of the two copper(I) atoms are three and four, Cu(1) forming an approximate trigonal planar coordination environment, while Cu(2) is a slightly distorted trigonal pyramidal geometry, resulting in a distorted chair‐like conformation. Complexes 1 and 2 are emissive in the solid state at ambient temperature, with the maxima at 552 and 602 nm, respectively, due to a MLCT excited state. Moreover, complex 3 manifests promising heterogeneous catalytic activities for the degradation of methylene blue (MB), with degradation efficiency of 99% under ambient light.     

A mixed‐ligand copper(II) complex that inhibits growth and induces apoptosis by DNA targeting in human epithelial cervical cancer cells

A new mixed‐ligand copper(II) complex, [Cu(L)(phen)]⋅MeOH (L = 4‐chloro‐2‐[(2‐hydroxyphenyl)iminomethyl]phenol), was synthesized. It belongs to the orthorhombic crystal system and Cu(II) is five‐coordinated in a seriously distorted square pyramidal geometry. DNA binding experiments confirmed an intercalative mode of interaction of the complex with calf thymus DNA. In a DNA cleavage experiment with the complex, as hydrogen peroxide was involved, oxidative DNA cleavage occurred and double‐stranded breaks even appeared at certain concentration. The strong interaction with bovine serum albumin suggested that the complex might be transported by protein. The complex exhibited more significant cytotoxicity in HeLa cells (IC₅₀ = 0.46 ± 0.01 μM) for 48 h, compared with cisplatin (10.61 ± 0.86 μM). This work indicated that the complex could induce apoptosis in a dose‐dependent manner and was associated with cell cycle arrest to some extent. Being consistent with the results of DNA cleavage experiment, comet assay indicated that the complex induced severe DNA fragmentation. The results showed the production of reactive oxygen species increased with increasing concentration of the complex. The complex was suggested to be capable of promoting HeLa cell apoptosis through an oxidative DNA damage pathway.     

A new one‐dimensional cadmium(II) coordination polymer incorporating 4‐[4‐(1H‐imidazol‐1‐yl)phenyl]pyridine and 5‐hydroxybenzene‐1,3‐dicarboxylate ligands

The design and synthesis of new organic lgands is important to the rapid development of coordination polymers (CPs). However, CPs based on asymmetric ligands are still rare, mainly because such ligands are usually expensive and more difficult to synthesize. The new asymmetric ligand 4‐[4‐(1H‐imidazol‐1‐yl)phenyl]pyridine (IPP) has been used to construct the title one‐dimensional coordination polymer, catena‐poly[[[aqua{4‐[4‐(1H‐imidazol‐1‐yl‐κN³)phenyl]pyridine}cadmium(II)]‐μ‐5‐hydroxybenzene‐1,3‐dicarboxylato‐κ³O¹,O^1′:O³] monohydrate], {[Cd(C₈H₄O₅)(C₁₄H₁₁N₃)₂(H₂O)]·H₂O}_n, under hydrothermal reaction of IPP with Cd^II in the presence of 5‐hydroxyisophthalic acid (5‐OH‐H₂bdc). The Cd^II cation is coordinated by two N atoms from two distinct IPP ligands, three carboxylate O atoms from two different 5‐OH‐bdc²⁻ dianionic ligands and one water O atom in a distorted octahedral geometry. The cationic [Cd(IPP)₂]²⁺ nodes are linked by 5‐OH‐bdc²⁻ ligands to generate a one‐dimensional chain. These chains are extended into a two‐dimensional layer structure via O—H…O and O—H…N hydrogen bonds and π–π interactions.     

Structural comparison of group 7 tricarbonyl complexes of 2‐{[2‐(1H‐imidazol‐4‐yl)ethyl]iminomethyl}‐5‐methylphenolate

Two tricarbonyl complexes of rhenium(I) and manganese(I) coordinated by the ligand 2‐{[2‐(1H‐imidazol‐4‐yl)ethyl]iminomethyl}‐5‐methylphenolate are reported, viz. fac‐tricarbonyl(2‐{[2‐(1H‐imidazol‐4‐yl‐κN³)ethyl]iminomethyl‐κN}‐5‐methylphenolato‐κO)rhenium(I) methanol monosolvate, [Re(C₁₆H₁₄N₃O₄)(CO)₃]·CH₃OH, (I), and fac‐tricarbonyl(2‐{[2‐(1H‐imidazol‐4‐yl‐κN³)ethyl]iminomethyl‐κN}‐5‐methylphenolato‐κO)manganese(I), fac‐[Mn(C₁₆H₁₄N₃O₄)(CO)₃], (II), display facial coordination in a distorted octahedral environment. The crystal structure of (I) is stabilized by O—H...O, N—H...O and C—H...O hydrogen‐bond interactions, while that of (II) is stabilized by N—H...O hydrogen‐bond interactions only. These interactions result in two‐dimensional networks and π–π stacking for both structures.     

Syntheses and structures of discrete copper(II) and cadmium(II) supramolecular complexes based on 1,4‐diacylthiosemicarbazone ligands

Thiosemicarbazides and their metal complexes have attracted considerable interest because of their biological activities and their flexibility, which allows the ligands to bend and rotate freely to accommodate the coordination geometries of various metal centres. Discrete copper(II) and cadmium(II) complexes have been prepared by crystallization of N‐[2‐(2‐hydroxybenzoyl)hydrazinecarbonothioyl]propanamide (H₃L) with Cu(CH₃COO)₂ or Cd(NO₃)₂ in a dimethylformamide/methanol mixed‐solvent system at room temperature, affording the complexes di‐μ‐acetato‐bis{μ₄‐1‐[(2‐oxidophenyl)carbonyl]‐2‐(propanamidomethanethioyl)hydrazine‐1,2‐diido}tetracopper(II) dimethylformamide disolvate, [Cu₄(C₁₁H₁₀N₃O₃S)₂(C₂H₃O₂)₂]·2C₃H₇NO, (I), and bis{μ₂‐[(2‐hydroxyphenyl)formamido](propanamidomethanethioyl)azanido}bis[(4,4′‐bipyridine)nitratocadmium(II)] dihydrate, [Cd₂(C₁₁H₁₂N₃O₃S)₂(NO₃)₂(C₁₀H₈N₂)₂]·2H₂O, (II). Complex (I) consists of four Cu^II cations, two μ₄‐bridging trianionic ligands and two μ₂‐bridging acetate ligands, while complex (II) is composed of two Cd^II cations, two μ₂‐bridging monoanionic ligands, two nitrate ligands and two 4,4′‐bipyridine ligands. These discrete complexes are connected by hydrogen bonds and van der Waals interactions to form a three‐dimensional supramolecular architecture. Compared with (I), the phenolic hydroxy group and hydrazide N atom of the thiosemicarbazide ligand of (II) are not involved in coordination and lead to a binuclear Cd^II complex. This different coordination mode may be attributed to the larger ionic radius of the Cd^II ion compared with the Cu^II ion.     

Synthesis and coordination chemistry of the PPN ligand 2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine

The synthesis and crystal structure of the multidentate PPN ligand 2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine (L ), C₁₉H₃₅NP₂, are described. In the isostructural tetrahedral Fe and Co complexes of type LM Cl₂ (M = Fe, Co), namely {2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine‐κ²P ,N }dichloridoiron(II), [FeCl₂(C₁₉H₃₅NP₂)], and {2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine‐κ²P ,N }dichloridocobalt(II), [CoCl₂(C₁₉H₃₅NP₂)], the ligand adopts a bidentate P ,N‐coordination, whereas in the case of the octahedral Mn complex {2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine‐κ²P ,P ′}bromidotricarbonylmanganese(I), [MnBr(C₁₉H₃₅NP₂)(CO)₃], the ligand coordinates via both P atoms to the metal centre.     

A new copper(II) coordination polymer containing chains of interconnected paddle‐wheel antiferromagnetic clusters

The construction of supramolecular architectures based on inorganic–organic coordination frameworks with weak noncovalent interactions has implications for the rational design of functional materials. A new crystalline binuclear copper(II) one‐dimensional polymeric chain, namely catena‐poly[[[tetrakis(μ‐4‐azaniumylbutanoato‐κ²O :O ′)dicopper(II)(Cu —Cu )]‐μ‐chlorido‐[diaquadichloridocopper(II)]‐μ‐chlorido] bis(perchlorate)], {[Cu₃Cl₄(C₄H₉NO₂)₄(H₂O)₂](ClO₄)₂}_n , was obtained by the reaction of 4‐aminobutyric acid (GABA) with CuCl₂·2H₂O in aqueous solution. The structure was established by single‐crystal X‐ray diffraction and was also characterized by IR spectroscopy and magnetic measurements. The crystal structure consists of [{Cu₂(GABA)₄}{CuCl₄(H₂O)₂}]⁺ cations and isolated perchlorate anions. Two symmetry‐related Cu^II centres are bridged via carboxylate O atoms into a classical paddle‐wheel configuration, with a Cu…Cu distance of 2.643 (1) Å, while bridging Cl atoms complete the square‐pyramidal geometry of the metal atoms. The Cl atoms connect the paddlewheel moieties to a second Cu^II atom lying on an octahedral site, resulting in infinite helical chains along the c axis. The packing motif exhibits channels containing free perchlorate anions. The crystal structure is stabilized by hydrogen bonds between the perchlorate anions, the coordinated water molecules and the ammonium groups of the polymeric chains. The magnetic analysis of the title compound indicates a nontrivial antiferromagnetic behaviour arising from alternating weak–strong antiferromagnetic coupling between neighbouring Cu^II centres.     

Crystallographic report: Coordination polymers containing Cd(NO3)2 and Cd(H2O)22+ units bridged by btp ligands (btp = 2,6‐bis(N′‐1,2,4‐triazolyl)pyridine)

There are two kinds of coordination polymers in the title compound: one contains Cd(NO₃)₂ units bridged by 2,6‐bis(N′‐1,2,4‐triazolyl)pyridine (btp) ligands and the other contains Cd(H₂O)₂²⁺ bridged by btp ligands. The two coordination polymers are connected through hydrogen bonds. Copyright © 2004 John Wiley & Sons, Ltd.     

Mononuclear and three‐dimensional metal complexes based on a multidentate hydrazone ligand

A potentially pentadentate hydrazone ligand, N′‐[1‐(pyrazin‐2‐yl)ethylidene]nicotinohydrazide (HL), was prepared from the condensation reaction of nicotinohydrazide and acetylpyrazine. Reactions of HL with MnCl₂, Mn(CH₃COO)₂ and Cd(CH₃COO)₂ afforded three metal complexes, namely dichlorido{N′‐[1‐(pyrazin‐2‐yl‐κN¹)ethylidene]nicotinohydrazide‐κ²N′,O}manganese(II), [MnCl₂(C₁₂H₁₁N₅O)], (I), bis{N′‐[1‐(pyrazin‐2‐yl‐κN¹)ethylidene]nicotinohydrazidato‐κ²N′,O]manganese(II), [Mn(C₁₂H₁₀N₅O)₂], (II), and poly[[(acetato‐κ²O,O′){μ₃‐N′‐[1‐(pyrazin‐2‐yl‐κ²N¹:N⁴)ethylidene]nicotinohydrazidato‐κ³N′,O:N¹}cadmium(II)] chloroform disolvate], {[Cd(C₁₂H₁₀N₅O)(CH₃COO)]·2CHCl₃}_n, (III), respectively. Complex (I) has a mononuclear structure, the Mn^II centre adopting a distorted square‐pyramidal coordination. Complex (II) also has a mononuclear structure, with the Mn^II centre occupying a special position (C₂ symmetry) and adopting a distorted octahedral coordination environment, which is defined by two O atoms and four N atoms from two N′‐[1‐(pyrazin‐2‐yl)ethylidene]nicotinohydrazidate (L⁻) ligands related via a crystallographic twofold axis. Complex (III) features a unique three‐dimensional network with rectangular channels, and the L⁻ ligand also serves as a counter‐anion. The coordination geometry of the Cd^II centre is pentagonal bipyramidal. This study demonstrates that HL, which can act as either a neutral or a mono‐anionic ligand, is useful in the construction of interesting metal–organic compounds.     

Supramolecular architectures in CoII and CuII complexes with thiophene‐2‐carboxylate and 2‐amino‐4,6‐dimethoxypyrimidine ligands

The coordination chemistry of mixed‐ligand complexes continues to be an active area of research since these compounds have a wide range of applications. Many coordination polymers and metal–organic framworks are emerging as novel functional materials. Aminopyrimidine and its derivatives are flexible ligands with versatile binding and coordination modes which have been proven to be useful in the construction of organic–inorganic hybrid materials and coordination polymers. Thiophenecarboxylic acid, its derivatives and their complexes exhibit pharmacological properties. Cobalt(II) and copper(II) complexes of thiophenecarboxylate have many biological applications, for example, as antifungal and antitumor agents. Two new cobalt(II) and copper(II) complexes incorporating thiophene‐2‐carboxylate (2‐TPC) and 2‐amino‐4,6‐dimethoxypyrimidine (OMP) ligands have been synthesized and characterized by X‐ray diffraction studies, namely (2‐amino‐4,6‐dimethoxypyrimidine‐κN)aquachlorido(thiophene‐2‐carboxylato‐κO)cobalt(II) monohydrate, [Co(C₅H₃O₂S)Cl(C₆H₉N₃O₂)(H₂O)]·H₂O, (I), and catena‐poly[copper(II)‐tetrakis(μ‐thiophene‐2‐carboxylato‐κ²O:O′)‐copper(II)‐(μ‐2‐amino‐4,6‐dimethoxypyrimidine‐κ²N¹:N³)], [Cu₂(C₅H₃O₂S)₄(C₆H₉N₃O₂)]_n, (II). In (I), the Co^II ion has a distorted tetrahedral coordination environment involving one O atom from a monodentate 2‐TPC ligand, one N atom from an OMP ligand, one chloride ligand and one O atom of a water molecule. An additional water molecule is present in the asymmetric unit. The amino group of the coordinated OMP molecule and the coordinated carboxylate O atom of the 2‐TPC ligand form an interligand N—H…O hydrogen bond, generating an S(6) ring motif. The pyrimidine molecules also form a base pair [R₂²(8) motif] via a pair of N—H…N hydrogen bonds. These interactions, together with O—H…O and O—H…Cl hydrogen bonds and π–π stacking interactions, generate a three‐dimensional supramolecular architecture. The one‐dimensional coordination polymer (II) contains the classical paddle‐wheel [Cu₂(CH₃COO)₄(H₂O)₂] unit, where each carboxylate group of four 2‐TPC ligands bridges two square‐pyramidally coordinated Cu^II ions and the apically coordinated OMP ligands bridge the dinuclear copper units. Each dinuclear copper unit has a crystallographic inversion centre, whereas the bridging OMP ligand has crystallographic twofold symmetry. The one‐dimensional polymeric chains self‐assemble via N—H…O, π–π and C—H…π interactions, generating a three‐dimensional supramolecular architecture.     

Synthesis and Crystal Structure of a Decanuclear Silver（I）-thiolate Compound Ag10S[S2P（OEt）2]8

A new decanuclear silver(I) compound Ag₁₀(μ₈‐S)(dtp)₈ [dtp=S₂P(OEt)₂] was isolated from a reaction mixture containing W₂S₄(dtp)₂ and AgN0₃, and its solid‐state molecular structure was determinated by X‐ray crystallography. The crystallographic study revealed that the compound contains a distorted mono‐capped quasi‐prism [Ag_io] with an octat‐bridging S atom at the center of the prism. The compound (C₃₂H₈₀Ag₁₀O₁₆P₈S₁₇, M_r=2592.46) crystallizes in the monoclinic P2₁/n space group, with a = 1.5111(5) nm, b=2.3656(8) nm, c=2.284(1) nm, β= 96.88(3)°, V=8.107(5) nm³, Z=4 and D,=2.12 g · cm^?3. The solution using direct method and full‐matrix least‐squares refinement led to R=0.066, Rw=0.078 for 3928 reflections with I3σ(I).     

Structure and magnetic properties of a mixed‐ligand copper(II) complex

The hydrothermal synthesis of the novel complex poly[[μ₂‐N¹,N⁴‐bis(pyridin‐3‐yl)naphthalene‐1,4‐dicarboxamide‐κ²N³:N^3′](μ₄‐phthalato‐κ⁴O¹:O¹:O^1′:O^2′)copper(II)], [Cu(C₈H₄O₄)(C₂₂H₁₆N₄O₂)]_n, is described. With the phthalate ligand connecting neighbouring Cu^II cations, an infinite one‐dimensional chain is formed. Adjacent one‐dimensional chains are connected by the dicarboxamide ligand, forming an intriguing two‐dimensional framework. The magnetic properties and thermal stability of this complex are also described.     

Synthesis,crystal structure and magnetic properties of the binuclear copper (II) complex of a new bis (1, 4, 7, 10‐tetraazacyclododecane) ligand

A new binucleating macrocyclic ligand 2,6‐bis (1,4,7,10‐tetraazacyclododecan‐10‐ylmethyl) methoxy‐benzene (L) and its binuclear copper (II) complex, [Cu₂LBr₂] (CIO₄ )₂ · 3H₂O (1), was prepared and the structure was determined by X‐ray crystallography. Complex 1 crystallizes in monoclinic crystal system, P2₁/n space group with a = 0.8206(3), b =2.0892(8), c = 2.3053(7) mn, β = 95.83(2)°, V = 3.932 nm³, Mr=1017.57, Z = 4, D_c =1.692 g/cm³, and R= 0.0489, R_w 0.0552 for 6571 observed reflections with I ≥ 2σ (1). Both of the copper(II) centers are coordinated by four amine nitrogen donors of cyclen subunits and a bromide anion, and each copper(II) ion is in a square‐pyramidal coordination environment. Variable temperature magnetic susceptibility studies indicate that there exists weak intramolecular antiferro‐magnetic coupling ( ?2J = 2.06 cm^?1) between the two copper (II) centers.     

Synthesis,crystal structures and spectral properties of cobalt (Ⅱ) complexes:[ CoL (N_3) ] ·ClO_4 and CoL (N_3)_2 [L=tris ((3,5-dimethylpyrazol-1-yl) methyl) amine

Two monomeric cobalt(Ⅱ)complexes,[CoL(N3)] ClO4(1)and CoL(N3)2(2),where L is tris((3,5-dimethylpyrazol-1-yl)methyl)amine,were synthesized and their crystal structures were determined by X-ray diffraction technique.Complex 1 is five coordinated with one azide nitrogen atom and four nitrogen atoms of the tris((3,5-dimethylpyrazol-l-yl)-methyl)amine ligand,and the metal center is in distorted trigonal bipyramidal environment.Complex 2 is six coordinated distorted octahedron with the two azide nitrogen atoms and four nitrogen donors of the tris((3,5-dimethylpyrazol-1-yl)-methyl)amine ligand.The solution behaviors of the title complexes have been further investigated by UV-Vis,and 1H NMR analysis.It is found that the formation of 1 and 2 depends on the molar ratio of the azide ion to metal salt and ligand Complex 1 attached with one azide group is more stable and easy to generate than complex 2 incorporated with two azide groups,and the reasons were well discussed.     

Synthesis,crystal structures and characterizations of three new copper(II) complexes including anti‐inflammatory diclofenac

Three new diclofenac‐based copper(II) complexes, namely tetrakis{μ‐2‐[2‐(2,6‐dichloroanilino)phenyl]acetato‐κ²O:O′}bis(methanol‐κO)copper(II), [Cu₂(μ‐dicl)₄(CH₃OH)₂] ( 1 ), bis{2‐[2‐(2,6‐dichloroanilino)phenyl]acetato‐κ²O,O′}bis(1‐vinyl‐1H‐imidazole‐κN³)copper(II), [Cu(dicl)₂(vim)₂] ( 2 ), and bis{2‐[2‐(2,6‐dichloroanilino)phenyl]acetato‐κ²O,O′}bis(1H‐imidazole‐κN³)copper(II), [Cu(dicl)₂(im)₂] ( 3 ) [dicl is diclofenac (C₁₄H₁₀Cl₂NO₂), vim is 1‐vinylimidazole (C₅H₆N₂) and im is imidazole (C₃H₄N₂)], have been synthesized and characterized by elemental analysis, FT–IR spectroscopy, thermal analysis and single‐crystal X‐ray diffraction. X‐ray diffraction analysis shows that complex 1 consists of dimeric units in which the dicl ligand exhibits a bidentate syn,syn‐μ₂ coordination mode linking two copper(II) centres. Complexes 2 and 3 have mononuclear units with the general formula [Cu(dicl)₂L₂] (L is vim or im) in which the Cu^II ions are octahedrally coordinated by two L and two dicl chelating ligands. The L and dicl ligands both occupy the trans positions of the coordination octahedron. The different coordination modes of dicl in the title complexes were revealed by Fourier transform IR (FT–IR) spectroscopy. The spin matching between the copper(II) centres in the dimeric [Cu₂(μ‐dicl)₄(CH₃OH)₂] units was also confirmed by magnetic data to be lower than the spin‐only value and electron paramagnetic resonance (EPR) spectra. The thermal properties of the complexes were investigated by thermogravimetric (TG) and differential thermal analysis (DTA) techniques.     

A new nano‐sized mononuclear Cu (II) complex with N,N‐donor Schiff base ligands: sonochemical synthesis,characterization, molecular modeling and biological activity

A new, simple Cu²⁺ nano‐structure Schiff base complex in methanol medium has been synthesized by the ultrasonic method. Structure of the compound was confirmed by FT‐IR, GC‐Mass and other spectroscopic techniques. The copper oxide (CuO) was achieved from the copper nano‐structure Schiff base complex as the raw material after calcination for 3 hr at 600 °C. According to results Cu²⁺ gives a complex with mole ratio 1:2 of metal to ligand (ML₂) with Schiff base which a distorted square planer is the most probable geometry for it. The calculations results from XRD patterns propose the nano‐sized complexes. The SEM images show morphology of both the copper complex and the CuO powder were plate‐like. The metal chelates of Cu²⁺ in two states of bulk and nano have been screened for their in vitro antibacterial activity against four bacteria, gram‐positive (Staphylococcus aureus) and gram‐negative (Escherichia coli) and three strains of fungus (Aspergillus flavus). The nano metal chelates were shown to possess more antibacterial activity than the bulk chelate. Finally, the empirical parameters of Schiff base compounds showed a good agreement with theoretical ones.