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.     

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 1D coordination polymers from nickel(II) tetraaza macrocycle and carboxylate ligands

Reactions of [Ni(L)]Cl₂ · 2H₂O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) with isophthalic acid (H₂isoph) and 1,3,5-cyclohexanetricarboxylic acid (H₃chtc) yield the 1D nickel(II) complexes {[Ni(L)(isoph)] · 3H₂O}_n (1) and {[Ni(L)(H-chtc)] · H₂O}_n (2). The structures were characterized by X-ray crystallography, spectroscopic and magnetic susceptibility. The crystal structures of the 1D chain compounds 1 and 2 show an elongated distorted octahedron about each nickel(II) ion. The magnetic behavior of two compounds exhibits weak intrachain antiferromagnetic interaction with J values of −0.93 cm⁻¹ for 1 and −1.28 cm⁻¹ for 2. The electronic spectra of the complexes are significantly affected by the nature of the carboxylate ligands.     

Heteronuclear M(II)-Ln(III) (M = Co, Mn; Ln = La, Pr, Sm, Gd, Dy and Er) coordination polymers: Synthesis, structures and magnetic properties

Thirteen novel 3d-4f heteronuclear coordination polymers based on the pyridine-2,6-dicarboxylic acid (H₂pda) and imidazole ligands, HIm[(pda)₃MLn(Im)₂(H₂O)₂]·3H₂O (Im = imidazole; M = Co, Ln = Pr (1), Gd (2), Dy (3), Er (4); M = Mn, Ln = Pr (5), Sm (6), Gd (7), Dy (8), Er (9)), HIm[(pda)₃CoSm(Im)₂(H₂O)₂]·2H₂O (10), [(Im)₄M(H₂O)₂][(pda)₄La₂(H₂O)₂]·2H₂O (M = Co (11), Mn (12)), and [(pda)₆Co₃Pr₂(H₂O)₆]·6H₂O (13), have been prepared and structurally characterized. X-ray crystallographic analyses revealed that these complexes display four different types of structures. Complexes 1-9 are isostructural, and possess 1-D chain structures constructed by alternately arrayed nine-coordinated Ln(III) (Ln = Pr, Sm, Gd, Dy, Er) and six-coordinated M(II) (M = Mn, Co) ions. Complex 10 exhibits a unique one-dimensional structure, in which two independent chains are parallel viewed down the a-axis and anti-parallel viewed down the c-axis. Complexes 11 and 12 are isostructural and display 1-D homometallic chain structures. Complex 13 is a 3D framework fabricated through PrN₃O₆ and CoO₆ polyhedrons as building blocks. The variable-temperature solid-state dc magnetic susceptibilities of complexes 2, 3, 4, 9 and 13 have been investigated. Antiferromagnetic exchange interactions were determined for these five complexes.     

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.     

Syntheses, crystal structures of a series of copper(II) complexes and their catalytic activities in the green oxidative coupling of 2,6-dimethylphenol

Three mixed-ligand Cu^II complexes bearing iminodiacetato (ida) and N-heterocyclic ligands, namely, [Cu₂(ida)₂(bbbm)(H₂O)₂] · H₂O (1), [Cu₂(ida)₂(btx)(H₂O)₂] · 2H₂O (2) and [Cu₂(ida)₂(pbbm)(H₂O)₂] · H₂O · 3CH₃OH (3) (bbbm = 1,1^′-(1,4-butanediyl)bis-1H-benzimidazole, btx = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, pbbm = 1,1^′-(1,3-propanediyl)bis-1H-benzimidazole), in addition to three fcz-based Cu^II complexes, namely, {[Cu(fcz)₂(H₂O)₂] · 2NO₃}_n (4), {[Cu(fcz)₂(H₂O)] · SO₄ · DMF · 2CH₃OH · 2H₂O}_n (5) and {[Cu(fcz)₂Cl₂] · 2CH₃OH}_n (6) (fcz = 1-(2,4-difluorophenyl)-1,1-bis[(1H-1,2,4-triazol-l-yl) methyl]ethanol) have been prepared according to appropriate synthetic strategies with the aim of exploiting new and potent catalysts. Single crystal X-ray diffraction shows that 1 and 2 possess similar binuclear structures, 3 features a 2D pleated network, and 4 exhibits a 1D polymeric double-chain structure. Complexes 1-6 are tested as catalysts in the green catalysis process of the oxidative coupling of 2,6-dimethylphenol (DMP). Under the optimized reaction conditions, these complexes are catalytically active by showing high conversion of DMP and high selectivity of PPE. The preliminary study of the catalytic-structural correlations suggests that the coordination environment of the copper center have important influences on their catalytic activities.     

New metal–organic architectures of cobalt(II), nickel(II) and zinc(II) with tripodal ligand 5-(1H-imidazol-4-ylmethyl)aminoisophthalic acid

Four new coordination polymers {[Ni(HL)(H₂O)]·H₂O}_n (1), {[Co(HL)(H₂O)]·H₂O}_n (2), {[Co(HL)]·4H₂O}_n (3) and {[Zn(HL)]·2H₂O·0.5C₂H₅OH}_n (4) [H₃L = 5-(1H-imidazol-4-ylmethyl)aminoisophthalic acid] have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses. Complexes 1 and 2 display (3, 3)-connected 2D network with (4, 8²) topology. While 3 and 4 exhibit a binodal (3, 6)-connected 2D network with a Schläfli symbol (4³)₂(4⁶, 6⁶, 8³). The complexes 1–4 show remarkable thermal stability and 4 exhibits blue fluorescence with maximum emission at 413 nm upon excitation at 362 nm in the solid state at room temperature. In addition, the magnetic measurements of 3 indicate that there are antiferromagnetic interactions between the neighboring Co(II) centers.     

Hypervalence in germanium compounds containing the tetracylic moiety {S(C6H3S)2O}Ge via O···Ge transannular interactions: A structural study

Treatment of R_nGeCl_4−n with {S(C₆H₃SH)₂O} (1) afforded the stable phenoxathiin-4,6-dithiolate compounds [{S(C₆H₃S)₂O}GeR₂] [n = 2; R = Et (2), Ph (3)] and [{S(C₆H₃S)₂O}GeRCl] [n = 1; R = Et (4), Ph (5)]. Treatment of GeCl₄ with 1 in benzene afforded the dichloro compound [{S(C₆H₃S)₂O}GeCl₂] (8) at 7 °C. Bromo compounds [{S(C₆H₃S)₂O}GeRBr] [R = Et (6), Ph (7)] and [{S(C₆H₃S)₂O}GeBr₂] (9) were synthesized by halogen exchange from the appropriate chloro derivative using KBr/HBr. X-ray structure determinations of diorganyl dithiolate compounds 2 and 3 revealed that germanium atom is contained in a boat–chair-shaped eight-membered central ring and displays a tetrahedral geometry. In contrast, compounds 4–6 display a boat–boat-shaped central ring with a significant intramolecular transannular O···Ge interaction. The geometry of the pentacoordinate Ge atom in these last complexes may be described as distorted trigonal bipyramidal with a 62–65% distortion displacement.     

Assembly and structures of five new Cu(II) complexes based on the V-shaped building block [Cu(dbsf)]

Five new copper(II) complexes [Cu(dbsf)(H₂O)]_n · 0.5n(i-C₃H₇OH) (1), [Cu(dbsf)(4,4′-bpy)_0.5]_n · nH₂O (2), [Cu(dbsf)(2,2′-bpy)(H₂O)]₂ · (n-C₃H₇OH) · 0.5H₂O (3), [Cu(dbsf)(phen)(H₂O)]₂ · 1.5H₂O (4) and [Cu(dbsf)(2,2′-bpy)(H₂O)]_n · n(i-C₃H₇OH) (5) (H₂dbsf = 4,4′-dicarboxybiphenyl sulfone, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, i-C₃H₇OH = isopropanol, n-C₃H₇OH = n-propanol) have been synthesized under hydro/solvothermal conditions. All of the complexes are assembled from V-shaped building blocks, [Cu(dbsf)]. Complex 1 is composed of 1D double-chains. In complex 2, dbsf²⁻ ligands and 4,4′-bpy ligands connect Cu(II) ions into catenane-like 2D layers. These catenane-like 2D layers stack in an ABAB fashion to form a 3D supramolecular network. Complexes 3 and 4 are 0D dimers, in which two [Cu(dbsf)] units encircle to form dimetal macrocyclic molecules. However, in complex 5, the V-shaped building blocks [Cu(dbsf)] are joined head-to-tail, resulting in the formation of infinite tooth-like chains. The different structures of complexes 3 and 5 may be attributed to the different solvent molecules included.     

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.     

Solvothermal syntheses and crystal structures of new Cu(II) complexes with phenylsuccinic acid

Five new Cu(II) complexes [Cu(psa)(phen)] · 3H₂O (1), [Cu(psa)(2bpy)] · 0.5H₂O (2), [Cu(psa)(2bpy)(H₂O)] · 3H₂O (3), [Cu(psa)(4bpy)] · H₂O (4), and [Cu(psa)_0.5(N₃)(2bpy)] (5) (H₂psa = phenylsuccinic acid, phen = 1,10-phenanthroline, 2bpy = 2,2′-bipyridine, and 4bpy = 4,4′-bipyridine) were obtained under solvothermal conditions and characterized by single-crystal X-ray diffraction. Complexes 2 and 3 were formed by one-pot reaction. In complex 2, Cu(II) ion is four-coordinated and locates at a slightly distorted square center. In complex 3, the coordinated water molecule occupies the axial site of Cu(II) ion forming a tetragonal pyramid geometry. Complexes 1 and 3 are of 1D chain structures, and extended into 2D supramolecular network by hydrogen bonds. Complex 2 is of zipper structure, and further assembled into 2D supramolecular network by hydrogen bonds and π–π stacking interactions. Complex 4 is a 3D CdSO₄-like structure with twofold interpenetration, while complex 5 is a dinuclear compound. The different structures of complexes 1–5 can be attributed to using the auxiliary ligands, indicating an important role of the auxiliary ligands in assembly and structure of the title complexes.     

Syntheses,crystal structures,and magnetic and luminescent properties of a series of lanthanide coordination polymers with chelidamic acid ligand

A series of lanthanide(III) complexes with chelidamic acid ligand, [Ln(C₇H₂NO₅)·3H₂O]_n·nH₂O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd₂(C₇H₂NO₅)₃·4H₂O]_n·2nH₂O (5) and [Ce(C₇H₂NO₅)·1.5H₂O]_n (6), have been synthesized by hydrothermal method and structurally characterized by single-crystal X-ray diffraction. Complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (4⁴) topology 2D network. The variable-temperature magnetic properties of 3 and 5 have been investigated. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied.     

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.     

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.     

A series of 2D lanthanide (III) coordination polymers constructed from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate

Reactions of 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylic acid (H₃PyIDC) with a series of Ln(III) ions affords ten coordination polymers, namely, {[Ln(H₂PyIDC)(HPyIDC)(H₂O)₂]·H₂O}_n [Ln=Nd (1), Sm (2), Eu (3) and Gd (4)], {[Ln(HPyIDC)(H₂O)₃]·(H₂PyIDC)·H₂O}_n [Ln=Gd (5), Tb (6), Dy (7), Ho (8) and Er (9)], and {[Y₂(HPyIDC)₂(H₂O)₅]·(bpy)·(NO₃)₂·3H₂O}_n (10) (bpy=4,4′-bipyridine). They exhibit three types of networks: complexes 1-4 are isomorphous coordination networks containing neutral 2D metal-organic layers, while complexes 5-9 are isomorphous, which consist of cationic metal-organic layers and anionic organic layers, and complex 10 is a 2D network built up from 4-connected HPyIDC²⁻ anion and 4-connected Y(III) ions. In addition, thermogravimetric analyses and solid-state luminescent properties of the selected complexes are investigated. They exhibit intense, characteristic emissions in the visible region at room temperature.     

Structural and spectral investigations on some new Ni(II) complexes of di-2-pyridyl ketone N(4)-phenylthiosemicarbazone

Ni(II) complexes (1–5) of di-2-pyridyl ketone N(4)-phenylthiosemicarbazone (HL) have been synthesized and spectrochemically characterized. Elemental analyses revealed a NiL₂ · 2H₂O stoichiometry for compound 1. However, the single crystals isolated revealed a composition NiL₂ · 0.5(H₂O)0.5(DMF). The compound crystallizes into a monoclinic lattice with the space group P2₁/n. Complexes 2, 3 and 4 are observed to show a 1:1:1 ratio of metal:thiosemicarbazone:gegenion, with the general formula NiLX · yH₂O [X = NCS, y = 2 for 2; X = Cl, y = 3 for 3 and X = N₃, y = 4.5 for 4]. Compound 5 is a dimer with a metal:thiosemicarbazone:gegenion ratio of 2:2:1, with the formula [Ni₂L₂(SO₄)] · 4H₂O.     

Syntheses,structures, network topologies and photoluminescence of four Zn(II) and Cd(II) coordination polymers based on 5-carboxyl-1-carboxymethyl-2-oxidopyridinium

5-Carboxyl-1-carboxymethyl-2-oxidopyridinium (H₂CCOP) and a combination of N-donor ligands, such as 4,4′-bipyridine (4,4′-bipy) and 1,10-phenanthroline (phen) with d¹⁰ metal ions Zn(II) and Cd(II) give rise to four coordination polymers, namely, [Zn₂(CCOP)(OH)₂(H₂O)] (1), [Zn(CCOP)(phen)(H₂O)]·H₂O (2), [Cd(CCOP)(H₂O)₂]·3H₂O (3), and [Cd(CCOP)(H₂O)] (4). Polymer 1 features an unusual bilayer motif and forms the final (3,8)-connected 3D topology by hydrogen bonds. Polymer 2 consists of one-dimensional (1D) chains which are further connected with each other via hydrogen bonds to form the final interesting (3,6)-connected rutile network. Polymer 3 is made up of an unusual 2D structure containing cylinder channels in the b axis and features the (4,4)-connected 3D network by hydrogen bonds. Polymer 4 presents an interesting uninodal 4-connected net compared to polymer 3. These four coordination polymers are obtained by evaporation or hydrothermal route and characterized by analytical, spectroscopic, and crystallographic methods. Photoluminescence studies revealed that these four coordination polymers display structure-related fluorescent emission bands (λ_ex = 342 nm) at 361 nm for polymer 1, 404 nm for polymer 2, 367 nm for polymer 3, and 371 nm for polymer 4 in the solid state at room temperature.     

New copper(II) 1D polymer containing dimethyl(phenylsulfonyl)amidophosphate: Synthesis,crystal structure and magnetic properties

The reaction of sodium dimethyl(phenylsulfonyl)amidophosphate NaL (HL = C₆H₅SO₂NHP(O)(OCH₃)₂) with Cu(NO₃)₂ · 6H₂O and o-bpe (1,2-bis(pyridine-2-yl)ethane) in appropriate ratios, afford the formation of 1D coordination polymer [Cu(L)₂ · o-bpe]_n in good yield. The crystal structures of HL (1) and [Cu(L)₂ · o-bpe]_n (2) are reported. In the crystal package the molecules of 1 are linked by intermolecular hydrogen bonds formed by the phosphoryl oxygen atoms which serve as acceptors and nitrogen atoms of amide groups as donors. The crystal structure of 2 indicates the presence of unsaturated Cu(L)₂ unit bridged by o-bpe ligand in the one-dimensional polymeric chain. The Cu(II) atoms have distorted 4 + 2 octahedral CuO₄N₂ environment formed by the oxygen atoms belonging to the sulfonyl and phosphoryl groups of two deprotonated chelate ligands and nitrogen atoms of the bridging o-bpe ligands.     

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.     

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.