Syntheses,supramolecular structures and properties of six coordination complexes based on 5-sulfosalicylic acid and bipyridyl-like chelates

Six new complexes constructed by 5-sulfosalicylic acid and bipyridyl-like ligands (2,2′-bipy and 1,10-phen), namely [Cu₄(OH)₂(ssal)₂(phen)₄ · 7H₂O] (1), [Cu₄(OH)₂(ssal)₂(bipy)₄ · 2H₂O] (2), [Cd(Hssal)(bipy)] (3), [Cd(HL)₂(phen)₂] (4), [Cr(ssal)(bipy)(H₂O)₂ · 2H₂O] (5) and [Cr(ssal)(phen)₂] (6) (H₃ssal = 5-sulfosalicylic acid, H₂L = p-hydroxybenzenesulfonic acid, bipy = 2,2′-bipy, phen = 1,10-phen) were prepared under hydrothermal conditions and their structures were determined by single-crystal X-ray diffraction. Complexes 1 and 2 are both tetranuclear copper complexes with a stepped topology. In complex 3, a new coordination mode of the Hssal²⁻ group is reported in this work. During the synthetic process of complex 4, in situ decarboxylation of 5-sulfosalicylic acid into p-hydroxybenzenesulfonic acid is involved. Two chromium 5-sulfosalicylates (5 and 6) are reported for the first time. These new complexes display different supramolecular structures by O–H?O, C–H?O hydrogen bonds as well as π?π, C–H?π and O?π interactions. The results of magnetic determination show that ferromagnetic interactions exist in complex 1, however, antiferromagnetic interactions exist in 2.     

Interaction of copper(II) and palladium(II) with linked 2,2′-dipyridylamine derivatives: Synthetic and structural studies

Interaction of copper(II) salts with 2,2′-dipyridylamine (1), N-cyclohexylmethyl-2,2′-dipyridylamine (2), di-2-pyridylaminomethylbenzene (3), 1,2-bis(di-2-pyridylaminomethyl)-benzene (4), 1,3-bis(di-2-pyridylaminomethyl)benzene (5), 1,4-bis(di-2-pyridylaminomethyl)benzene (6), 1,3,5-tris(di-2-pyridylaminomethyl)benzene (7) and 1,2,4,5-tetrakis(di-2-pyridylaminomethyl)benzene (8) has yielded the following complexes: [Cu(2)(μ-Cl)Cl]₂, [Cu(3)(μ-Cl)Cl]₂ · H₂O, [Cu₂(4)(NO₃)₄], [Cu₂(5)(NO₃)₄] · 2CH₃OH, [Cu₂(6)(CH₃OH)₂(NO₃)₄], [Cu₄(8)](NO₃)₄] · 4H₂O while complexation of palladium(II) with 1, 4, 5 and 6 gave [Pd(1)₂](PF₆)₂ · 2CH₃OH, [Pd₂(4)Cl₄], [Pd₂(4)(OAc)₄], [Pd₂(5)Cl₄], [Pd₂(6)Cl₄] and [Pd₂(6)(OAc)₄] · CH₂Cl₂, respectively. X-ray structures of [Cu(2)(μ-Cl)Cl]₂, [Cu(3)(μ-Cl)Cl]₂ · 2C₂H₅OH, [Cu₂(6)(CH₃OH)₂(NO₃)₄], [Pd(1)₂](PF₆)₂ · 2CH₃OH, [Pd₂(4)(OAc)₄] · 4H₂O and [Pd₂(6)(OAc)₄] · 2CH₂Cl₂ are reported. In part, the inherent flexibility of the respective ligands has resulted in the adoption of a diverse range of coordination geometries and lattice arrangements, with the structures of [Pd₂(4)(OAc)₄] · 4H₂O and [Pd₂(6)(OAc)₄] · 2CH₂Cl₂, incorporating the isomeric ligands 4 and 6, showing some common features. Liquid–liquid (H₂O/CHCl₃) extraction experiments involving copper(II) and 1–3, 5, 7and 8 show that the degree of extraction depends markedly on the number of dpa-subunits (and concomitant lipophilicity) of the ligand employed with the tetrakis-dpa derivative 8 acting as the most efficient extractant of the six ligand systems investigated.     

Synthesis,structures and NLO properties of five non-centrosymmetric coordination compounds from the copper(II)/dps system (dps = 4,4′-dipyridyl sulfide)

The formation, crystal structure and properties of five copper(II) coordination compounds with the angular ligand, 4,4′-dipyridyl sulfide (dps) are described, {[Cu₃(μ-dps)₄(μ-SO₄)₂(SO₄)(H₂O)₅] · 10H₂O}_∞ (1 · 10H₂O), [Cu(dps)₄(H₂O)₂] · (ClO₄)₂ · H₂O (2 · H₂O), {[Cu(μ-dps)₂(DMF)₂](ClO₄)₂}_∞ (3), {[Cu(μ-dps)₂(H₂O)₂] · (NO₃)₂ · 2H₂O}_∞ (4 · 2H₂O) and {[Cu₃(μ-dps)₆(DMF)₂(H₂O)₄] · (NO₃)₆ · (DMF) · 6H₂O}_∞ (5 · DMF · 6H₂O). The topological architectures of all these coordination compounds are strongly dependent on the counteranions, with the aid of guest solvents, and include a chiral 3D non-interpenetrated structure for 1, an acentric mononuclear structure for 2, acentric 2D undulating networks for 3 and 5, and a chiral 1D double-stranded chain for 4. In particular, all these acentric or chiral coordination architectures are generated from an achiral ligand as a building unit, and their second-order non-linear optical (NLO) properties are also studied in this paper.     

Syntheses and study on nickel and copper complexes with 1,3,5-benzenetricarboxylic acid. Crystal and molecular structure of [Cu3(mdpta)3(btc)](ClO4)3 · 4H2O

Nickel and copper complexes containing 1,3,5-benzenetricarboxylic acid, with a combination of selected N-donor ligands and Schiff bases, of the composition Ni₃(bimz)₆(btc)₂ · 12H₂O (1), Ni₃(btz)₉(btc)₂ · 12H₂O (2), Ni₂(L₁)(btc) · 7H₂O (3), Ni₃(L₂)₂(Hbtc) · 9H₂O (4), Ni₂(L₃)(btc) · 4H₂O (5), Cu₂(L₄)(btc) · 7H₂O (6), [Cu₃(pmdien)₃(btc)](ClO₄)₃ · 6H₂O (7) and [Cu₃(mdpta)₃(btc)](ClO₄)₃ · 4H₂O (8); H₃btc = 1,3,5-benzenetricarboxylic acid, bimz = benzimidazole, btz = 1,2,3-benztriazole, L₁ = 2-[(phenylimino)methyl]phenol, L₂ = N,N′-bis-(salicylidene)propylenediamine, L₃ = 2-{[(2-nitrophenyl)methylene]amino}phenol, L₄ = 2-[(4-methoxy-phenylimino)methyl]phenol, pmdien = N,N,N′,N″,N″-pentamethyldiethylenetriamine, mdpta = N,N-bis-(3-aminopropyl)methylamine, have been synthesized. The complexes have been studied by elemental analysis, IR, UV–Vis spectroscopies, magnetochemical and conductivity measurements and selected compounds also by thermal analysis. The crystal and molecular structure of complex 8 was solved. The complex is trinuclear with btc³⁻-bridge. The coordination polyhedron around each copper atom can be described as a distorted square with a CuON₃ chromophore formed by one oxygen atom of carboxylate and three nitrogen atoms of mdpta. The magnetic properties of 8 have been studied in the 1.8–300 K temperature range revealing a very weak antiferromagnetic exchange interaction with J = −0.56 cm⁻¹ for g = 2.13(9). The antimicrobial activities against selected strains of bacteria were evaluated. It was found that only complex 5 is able to inhibit the growth of Staphylococcus strains.     

From discrete entity to three-dimensional architecture: Syntheses,crystal structures and optical properties of a series of transition metal complexes constructed from 4-carboxymethylbenzoic acid and 4,4′-bipyidine

Five new interesting transition metal coordination polymers [MnL₂(bpy)₂(H₂O)₂]_n (1) (H₂L = 4-carboxymethylbenzoic acid) (bpy = 4,4′-bipyidine), [CoL(bpy)(H₂O)₃ · H₂O]_n (2), [CdL(bpy)(H₂O)₃ · H₂O]_n (3), [Cu₂L(bpy)₂ · 3H₂O]_n (4) and [Zn₂L₂(bpy) · H₂O]_n (5) have been synthesized under solvothermal conditions and structurally characterized. This series of complexes has shown an intriguing variety of architectures, which firstly form zero- to two-dimensional frameworks by metal–ligand interactions, and secondly form three-dimensional supramolecular frameworks by intermolecular interactions such as hydrogen bonds. Compound 3 shows strong blue fluorescent emissions in the solid state upon photo-excitation at 359 nm at room temperature and may be an excellent candidate for blue-fluorescent materials. Compound 4 appears to be a good candidate for new hybrid inorganic–organic NLO materials.     

Syntheses and characterizations of nine coordination polymers of transition metals with carboxylate anions and bis(imidazole) ligands

Nine new compounds, namely [CuL1(biim-6)] · H₂O (1), [ZnL1(biim-6)] · H₂O (2), [MnL1(biim-6)] · H₂O (3), [MnL1(biim-4)] (4), [Co₂(L2)₂(biim-5)₃ · 6H₂O] · 8H₂O (5), [ZnL3(biim-6)] (6), [ZnL3(biim-5)] (7), [CdL3(biim-5) · 1.5H₂O] · 0.5H₂O (8) and [CdL4(biim-6) · 2H₂O] (9) [where L1 = oxalate anion, L2 = fumarate anion, L3 = phthalate anion, L4 = p-phthalate anion, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), biim-5 = 1,1′-(1,5-pentanedidyl)bis(imidazole) and biim-6 = 1,1′-(1,6-hexanedidyl)bis(imidazole)] were successfully synthesized. Compounds 1–3 are isostructural, and display 2D polymeric structures. Compound 4 shows a threefold interpenetrating diamondoid framework. In compound 5, the anions act as counterions, and the metal cations are bridged by bis(imidazole) ligands to form 1D polymeric chains. Compounds 6–9 show 2D polymeric structures. The magnetic properties for 1, 3 and 4 and luminescent properties for 2 and 6–9 are discussed. Thermogravimetric analyses (TGA) for these compounds are also discussed.     

Self assembly of asymmetric tetranuclear Cu(II) [2 × 2] grid-like complexes and of a dinuclear Ni(II) complex from pyridyl-phenol Schiff base ligands

Self assembly of N-salicylidene 2-aminopyridine (L1H) with Cu(NO₃)₂·3H₂O affords [Cu₄(L1)₄(NO₃)₃(CH₃OH)][Cu(L1)(NO₃)₂](2-aminopyridinium)(NO₃)·5CH₃OH (1) which is composed of an asymmetric [2 × 2] grid-like cationic complex that co-crystallizes with a Cu(II) mononuclear anion. This remarkable tetranuclear unit presents three penta-coordinated and one hexa-coordinated Cu(II) sites. This quadruple helicate structure reveals strong anti-ferromagnetic coupling (J = −340(2) cm⁻¹) between Cu(II) ions through a double alkoxo bridge. Reacting L1H with Cu(NO₃)₂·3H₂O in slightly different conditions affords however a more symmetric tetranuclear grid-like complex: [Cu₄(L1)₄(NO₃)₂(OH)₂](2-aminopyridinium)(OH)·CH₃OH) (2). A dinuclear Ni(II) complex, [Ni₂(L2)₂(L2H)₂(NCS)₂(CH₃OH)₂]·2CH₃OH (3), obtained with another related donor ligand (L2H = N-salicylidene 3-aminomethylpyridine) was also prepared.     

Preparation and structures of copper(II) and zinc(II) complexes with 5-ferrocenylpyrimidine: Structural variation derived from flexible coordination ability of the ligand and metal ions

5-Ferrocenylpyrimidine (FcPM) reacts with dinuclear copper(II) carboxylates ([Cu₂(RCOO)₄]; R = C₆H₅, C₅H₁₁, CH₃) to produce one-dimensional coordination polymers [Cu₂(C₆H₅COO)₄(FcPM)]_n (1), [Cu₂(C₅H₁₁COO)₄(FcPM)]_n · nCH₃CN (2), and a discrete tetranuclear complex [Cu₂(CH₃COO)₄(FcPM)₂] (3). Compounds 1 and 2 show similar zigzag chain structures, comprising alternate linking of FcPM and dinuclear copper(II) units, whereas the structure of 3 corresponds to the local structural motifs of 1 and 2. Reaction of FcPM with zinc salts (ZnX₂; X = NO₃, SCN) affords zinc-centered ferrocenyl cluster complexes, [Zn(NO₃)₂(FcPM)₃] (4) and [Zn(SCN)₂(FcPM)₂] · 0.5H₂O (5), with varying M:L ratios. FcPM acts as a bidentate ligand in 1 and 2, and as a monodentate ligand in the others.     

Syntheses,topological networks and properties of four complexes based on 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole ligand

Reactions of metal acetates with 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole (3-abpt) and co-ligands gave rise to four new complexes, namely [Zn₂(3-abpt)(beta)(DMF) (H₂O)₂]_n·nH₂O (1), [Zn(3-abpt)(ip)]_n·3nH₂O (2), [Zn(3-abpt)(ip)(H₂O)₂]_n·2nH₂O (3), and [Cu₂(3-abpt)₂(C₆H₅COO)₄(H₂O)₂]_n·2nH₂O (4) (ip = isophthalate, beta = 1,2,4,5-benzenetetracarboxylate). Compound 1 is a 3D coordination polymer with uncommon 3,4-connected (6².8)₂(6².8².10²) network. Compounds 2–4 are all 1D coordination polymers, which exhibit diversity structures. Compound 2 is a tubular-like chain, 3 is a ring-like network, and 4 is a zigzag chain. Their thermal stabilities and the photoluminescence of 1 have also been investigated.     

Crystal structure, spectroscopy and magnetism of trinuclear nickel(II), cobalt(II) complexes and their solid solution

Four new complexes [Ni₃(μ-L)₆(H₂O)₆](NO₃)₆·6H₂O (1), [Co₃(μ-L)₆(H₂O)₆](NO₃)₆·6H₂O (2), [Ni₃(μ-L)₆(H₂O)₄(CH₃OH)₂](NO₃)₆·4H₂O (3), [Co₃(μ-L)₆(H₂O)₄(CH₃OH)₂](NO₃)₆·4H₂O (4) (L = 4-amino-3,5-dimethanyl-1,2,4-triazole) were synthesized and structurally characterized by X-ray single-crystal diffraction. The structural analyses show that complex 1 and 2 are isomorphous; complex 3 and 4 are isomorphous. Four complexes all consist of the linear trinuclear cations ([M₃(μ-L)₆(H₂O)₆]⁶⁺ (M = Ni,Co) for 1 and 2; [M₃(μ-L)₆(H₂O)₄(CH₃OH)₂]⁶⁺ (M = Ni,Co) for 3 and 4), NO₃⁻ anions and crystallized water molecules. In the trinuclear cations, the central M(II) ions and two terminal M(II) ions are bridged by three triazole ligands. Other eleven solid solution compounds which are isomorphous with complex 3 and 4 were obtained by using different ratio of Ni(II) and Co(II) ions as reactants and ICP result indicates that ligand L has higher selectivity of Ni(II) ions than that of Co(II) ions. The magnetic analysis was carried out by using the isotropic spin Hamiltonian ? = −2J(?₁?₂ + ?₂?₃) (for complexes 1 and 3) and simultaneously considering the temperature dependent g factor (for complexes 2 and 4). Both the UV-Vis spectra and the magnetic properties of the solid solutions can be altered systematically by adjusting the Co(II)/Ni(II) ratio.     

Structural and magnetic properties of metal complexes with pyridine-2,6-dicarboxylate and 5-(4-bromophenyl)-2,4′-bipyridine

A series of complexes has been synthesized based on pyridine-2,6-dicarboxylate (L1) as the bridging ligand and 5-(4-bromophenyl)-2,4′-bipyridine (L2) as the pendant with different metal ions such as Ni^II, Co^II, and Cu^II, under hydrothermal conditions. In nickel and cobalt complexes [M(L1)(L2)₂ · H₂O]_n (M = Ni²⁺ or Co²⁺), the metal ions are bridged by L1 to form 1D coordination zigzag polymeric chains with L2 pendants possessing hexa-coordinated distorted octahedral geometries. While the copper ions are penta-coordinated by L1 and L2 with distorted square pyramidal geometries forming the tetranuclear cluster with the formula [Cu₄(L1)₄(L2)₄] · 2H₂O. It has been found that both the structure and magnetic property of these complexes are metal ions dependent. Intramolecular antiferromagnetic interactions were observed in the nickel and cobalt 1D coordination polymers, while ferromagnetic coupling was found in the tetranuclear copper cluster. Density functional theory calculations suggested that the O–C–O bridges of L1 in a basal–apical mode are responsible for intracluster intermetallic ferromagnetic exchange for the tetranuclear copper cluster.     

3D Heterometallic (3d–4f) coordination polymers: A ferromagnetic interaction in a Gd(III)–Cu(II) couple

Four 3d–4f heterometallic coordination polymers, [Cu₃(IDA)₆Ln₂] · n(H₂O) [IDA =  iminodiacetate dianion; Ln = Gd, n = 3 (1); Ln = Nd, n = 6 (2); Ln = Sm, n = 6 (3)] and [Cu(Cl)(NTA)Sm(H₂O)₆] · (ClO₄) · (H₂O) (4) [NTA = nitrilotriacetate trianion], have heen synthesized and characterized by single crystal X-ray diffraction analysis. Complexes 1–3 are isomorphous, showing a 3D coordination framework having tubular channels filled by lattice water molecules running parallel to the c axis. Whereas complex 4 is a 1D polymer of alternating copper and samarium ions connected by NTA, and the chains get involved in H-bonding interactions resulting in a 3D network. A low temperature magnetic study reveals ferromagnetic interactions for complex 1. Thermogravimetric and X-ray powder diffraction analyses of 1, 2 and 3 show that the covalently bonded 3D network remains almost unaffected after deaquation.     

Syntheses,structures and luminescent properties of four d-metal coordination polymers based on the 2,4,5-tri(4-pyridyl)-imidazole ligand

Four d¹⁰-metal coordination polymers based on the 2,4,5-tri(4-pyridyl)-imidazole ligand (Htpim), {[Zn₂(Htpim)₄Cl₄] · 8H₂O}_n (1), {[Cd(tpim)₂(H₂O)₂] · 4CH₃OH}_n (2), {[Cu₂(Htpim)(PPh₃)₂I₂] · CH₃CN}_n (3) and {[Ag(Htpim)](NO₃) · CH₂Cl₂}_n (4), have been synthesized and characterized by elemental analyses, IR, thermogravimetric and X-ray structural analyses. Both complexes 1 and 2 show one dimensional ribbon-like structures. Via intermolecular hydrogen bonds, a 2D supramolecular network and 3D framework are formed for 1 and 2, respectively. Complex 3 shows a 1D zigzag chain with a CuI₂Cu rhomboid dimer. Complex 4 shows a 1D ladder-like polymer with two different metallacycles. The luminescent properties of all the complexes have been studied in the solid state.     

Copper benzenedicarboxylate coordination polymers incorporating a long-spanning neutral co-ligand: Effect of anion inclusion and carboxylate pendant-arm length on topology and magnetism

Three divalent copper coordination polymers containing aromatic dicarboxylate ligands and the long-spanning tethering imine bis(4-pyridylmethyl)piperazine (bpmp) have been prepared and structurally characterized. The length of the dicarboxylate pendant arms, carboxylate binding mode, and the inclusion of anionic components play a synergistic role in structure direction in this system. {[Cu(ip)(bpmp)(H₂O)]·5H₂O}_n (ip = isophthalate, 1) displays neutral (4,4) rectangular coordination polymer grids that stack in an ABCD repeat pattern. Use of the longer pendant arm dicarboxylate 1,3-phenylenediacetate (phda) resulted in {[Cu₂(phda)₂(bpmp)]·H₂O}_n (2), a 3-D network coordination polymer with primitive cubic topology that features strongly antiferromagnetically coupled (J = −331(1) cm⁻¹) {Cu₂(CO₂)₄} paddlewheel units. In the presence of excess nitrate ions, {[Cu(phda)(Hbpmp)](NO₃)·3H₂O}_n (3) was isolated instead of 2; 3 manifests cationic 2-D coordination polymer layers built from weakly antiferromagnetically coupled (J = −2.43(1) cm⁻¹) {Cu₂O₂} dimers linked through phda and protonated bpmp ligands. The striking difference in magnetic properties is ascribed to the equatorial–equatorial versus axial–equatorial bridging of copper coordination spheres in 2 and 3, respectively.     

Synthetic,structural and spectroscopic studies of copper(II) complexes derived from the combination of the succinamate(−1) ligand with aromatic N,N′-chelates

The use of succinamic acid (H₂sucm)/N,N′-chelate (2,2′-bipyridine, bpy; 4,4′-dimethyl-2,2′-bipyridine, dmbpy; 1,10-phenanthroline, phen) ‘ligand blends’ in CuX₂·yH₂O (X = NO₃, y = 3; X = Cl, y = 0) chemistry has yielded the new complexes [Cu₂(Hsucm)₃(bpy)₂](NO₃)·0.5MeOH (1·0.5MeOH), [Cu₂(Hsucm)(OH)Cl(bpy)₂](OH)·3.6H₂O (5·3.6H₂O) and [Cu₂(Hsucm)₂Cl₂(phen)₂] (6). The succinamate(−1) ion behaves as a carboxylate ligand and exists in two different coordination modes in the structures of the above complexes, i.e., the common syn, syn μ₂-κO:κO′ in 1, 5 and 6, and the μ₂-κ²O:κO′ in 1. The primary amide group of Hsucm⁻ remains uncoordinated and participates in intermolecular hydrogen bonding interactions leading to 1D, 2D and 3D networks. Characteristic IR bands of the complexes are discussed in terms of the known structures and the coordination modes of the Hsucm⁻ ligands.     

Infinite chains constructed from flexible bis(benzimidazole)-based ligands

Two neutral ligands, L¹ · 2H₂O and L² · H₂O, and seven complexes, [Cu(pmb)₂(L¹)] (1), [Cu(pmb)₂(L²)] (2), [Cu(Ac)₂(L²)] · 4H₂O (3), [Cu(4-aba)₂(L²)] (4), [Ag(4-ts)(L¹)(H₂O)] (5), [Ag₂(epes)₂(L¹)] · 2H₂O (6), [Ag(1,5-nds)_0.5(L²)] · 0.5C₂H₅OH · H₂O (7) [where L¹ = 1,1′-(1,4-butanediyl)bis(2-methylbenzimidazole); L² = 1,1′-(1,4-butanediyl)bis(2-ethylbenzimidazole), pmb = p-methoxybenzoate anion; Ac = acetate anion; 4-aba = 4-aminobenzoate anion; 4-ts = p-toluenesulfonate anion; epes = N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonate) anion; 1,5-nds = 1,5-naphthalenedisulfonate anion], have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The L¹ and L² ligands in compounds 1–7 act as bridging ligands, linking metal ions into chain structures. The chains in compounds 3, 4 and 6 interlace with each other by hydrogen bonds to generate 3D supramolecular structures. In compound 5, π–π interactions between adjacent L¹ ligands hold the chains to a supramolecular layer. In compound 7, the sulfonate anions act as counterions in the framework. The thermal stabilities of 3, 6 and 7, and the luminescent properties for 5–7 in the solid states are also discussed.     

Synthesis,structures and biological properties of nickel(II) phthalates with imidazole and its derivatives

Four new nickel(II) phthalate compounds: mononuclear complexes [Ni(Im)]₆(Pht)·H₂O (1), [Ni(Pht)(Im)₃(H₂O)₂]·H₂O (2) and [Ni(Pht)(2-MeIm)₃(H₂O)₃]·H₂O (3), and coordination polymer [Ni(Pht)(4-MeIm)₂(H₂O)]_n (4) (where Pht = dianion of o-phthalic acid, Im = imidazole, 2-MeIm = 2-methylimidazole, 4-MeIm = 4-methylimidazole) have been synthesized. The complexes 1–4 were characterised by elemental analysis, IR data, thermogravimetric, and X-ray diffraction analyses. X-ray analysis shows that the asymmetric unit of 1 consists of [Ni(Im)]₆²⁺ cation, Pht²⁻ anion and solvate H₂O molecule. The phthalate dianion does not take part in coordination to metal ion. The cations, anions and water molecules are linked via   N–H?$?$O and O–H?$?$O interactions forming 2D hydrogen-bonded networks. The structures of 2 and 3 are similar to other mononuclear Ni(II) phthalate complexes where Pht²⁻ anions act as monodentate ligands and uncoordinated carboxylate oxygen atoms participate in the formation of hydrogen bonded double-chains. The structure of 4 consists of [Ni(4-MeIm)₂(H₂O)] building units connected by phthalate ions to form helical chains. The complexes 1–4 were tested for their ability to increase the biosynthesis of enzymes.     

Mononuclear,dinuclear and hydroxo-bridged tetranuclear complexes from reactions of Cu ions,mandelic acid and diimine ligands

The reaction of copper(II) hydroxocarbonate, mandelic acid (H₂MANO) and 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) in water affords [Cu(bpy)(μ₂-MANO)]₂ · 8H₂O (1), [Cu(bpy)(MANO)] · 4H₂O (2) and the opened tetranuclear hydroxo-bridged copper(II) complexes of formulae [Cu₄(μ₃-OH)₂(μ₂-MANO)₂(bpy)₄](phglyo)₂ · 8H₂O (3) (phglyo = phenylglyoxylate) or [Cu₄(μ₃-OH)₂(μ₂-OH)₂(OH₂)₂(phen)₄](Bza)₂(OH)₂ · 5H₂O (4) (Bza = benzoate), respectively. The compounds have been characterized by spectroscopic techniques and studied by single-crystal X-ray diffractometry. The formation of 3 and 4 takes place in basic media through dehydrogenation or oxidative dehydrogenation followed by in situ oxidative decarboxylation of mandelic acid to phenylglyoxylate or benzoate, respectively. These results indicate that cooperative catalysis of diimine ancillary ligands and copper(II) is essential.     

Anion effect on the construction of copper(II) coordination polymers with the twisted ligand bis(4-pyridylthio)methane

The reaction of CuSO₄ · H₂O with 4-bpytm [4-bpytm = bis(4-pyridylthio)methane] in EtOH afforded the complex [Cu(SO₄)(4-bpytm)(H₂O)₃] · H₂O (1 · H₂O) while the reaction of 4-bpytm with Cu(NO₃)₂ · 3H₂O in EtOH afforded the complex [Cu(NO₃)₂(4-bpytm)₂] · H₂O (2 · H₂O). The reaction of 4-bpytm with Cu(NO₃)₂ · 3H₂O in EtOH/dmf under microwave irradiation afforded the pseudo-polymorph [Cu(NO₃)₂(4-bpytm)₂] · Solv (2 · Solv). Compound 1 · H₂O forms helical chains while compounds 2 · H₂O and 2 · Solv are 2D coordination polymers with a (4,4) topology based on rhombic grids in 2 · H₂O and on a parquet motif in 2 · Solv. The 3D supramolecular organization through hydrogen bonding is analyzed for the three compounds and their thermal behaviour was also investigated.     

Assembly of silver(I) coordination polymers incorporating pyromellitic acid and N-heterocyclic ligands

Five mixed ligands coordination polymers [Ag₄(apym)₂(pma)·(H₂O)₂]_n (1), {[Ag₄(dmapym)₄(pma)·(H₂O)₂]·(H₂O)₆}_n (2), [Ag₂(apyz)₂(H₂pma)·(H₂O)₄]_n (3), {[Ag₄(apyz)₂(pma)·(H₂O)₂]·(H₂O)₂}_n (4) and [Ag₄(NH₃)₈(pma)·(H₂O)₆]_n (5) (apym = 2-aminopyrimidine, dmapym = 4, 6-dimethyl-2-aminopyrimidine, apyz = 2-aminopyrazine, H₄pma = pyromellitic acid) were synthesized and characterized. For 1 and 2, as the substituents change from H to methyl, the dimensions of 1–2 decrease from three-dimension (3D) to one-dimension (1D) due to the steric effect of methyl groups. For 3 and 4, as the ratios of Ag₂O/apyz/pma vary from 1:1:1 to 2:1:1, the structure of 3 is a 1D ladder structure built from Ag-apyz double chains and pma anions, while the structure of 4 is a two-dimension (2D) grid. As excess ammonia is added to above four reaction systems, the structure of 5 contains unprecedented {[Ag(NH₃)₂]⁺}_n chains and pma anions. The substituent on the pyrimidyl ring, ratios of reactants, solvent systems and ligand isomers intensively influence the coordination environments of metal ion and the coordination modes of the carboxyl group, and thus determine the structures of the coordination polymers. The photoluminescent properties of 1–5 were also investigated.