Syntheses, structures and properties of silver-organic frameworks constructed with 1,2,3,4-benzenetetracarboxylic acid

The reactions of 1,2,3,4-benzenetetracarboxylic acid (H(4)mpda) and different silver(I) salts under hydrothermal or solvent evaporation conditions yielded four unusual coordination complexes with interesting frameworks: [Ag(4)(mpda)](n) (1), {[Ag(2.5)(mpda)(bpy)(2)]·[Ag(bpy)]·[Ag(bpy)(H(2)O)]·(NO(3))(0.5)·(H(2)O)(9)}(n) (2), {[Ag(5)(mpda)(2)(bpy)(4)]·[Ag(bpy)]·[Ag(bpy)(H(2)O)]·[Ag(bpy)(H(2)O)]·(H(2)O)(16)}(n) (3), {[Ag(2)(mpda)(H(2)O)]·[Ag(bpy)]·[Ag(bpy)]}(n) (4) (bpy = 4,4'-bipyridine). Complex 1 displays a novel (3,4,7)-connected {4.6(2)}{4.6(5)}{4(2).6(13).8(5).10} topology, in which the carboxylic groups of the mpda(4-) ligand adopt variable coordination modes. In 1, besides Ag-O coordination bonding, AgAg and Agaromatic intermolecular interactions also make their appearance. In complexes 2-4, rare architectures comprising three or four isolated coordination polymers within the same crystalline structure have been obtained, respectively. In 2 and 3, neighboring layers are linked together through water tapes into a three-dimensional supramolecular architecture, which is also consolidated by π···π stacking, while independent infinite rod-like polymer chains fill the void space between layers. Interestingly, an anionic (H(2)O-NO(3)(-))(n) layer, built from water tapes and nitrate anions as well as consolidated by the mpda(4-) ligands, has been structurally identified in compound 2. A new water tape constructed from alternating tetramers and decamers has been obtained in compound 3. In compound 4, a right-handed helical chain and two rod-like polymeric chains are interconnected through host-guest molecular recognition to generate a three-dimensional chiral supramolecular architecture. Bulk materials for 1 and 4 have second-harmonic generation activity, being approximately 0.6 and 0.4 times that of urea. The IR spectra, thermogravimetric analysis and luminescent properties of all compounds were also investigated.     

Auxiliary ligand induced structural allomorphism in nanotubular microporous metal-organic frameworks based on discrete magnesium clusters

Three allomorphs with the same stoichiometry, [Mg(3)(H(2)O)(4)(5-aip)(2)(5-Haip)(2)]·4DMA, were solvothermally synthesized in the presence of different additives and represented the first 8-connected nanotubular networks in Mg-based metal-organic frameworks. The adsorption and delivery of drugs were also determined.     

New coordination polymers with extended arm cyclotriguaiacyclene ligands: 1D chains, and interpenetrating or polycatenating 2D (4(2).6(2))(4.6(2))2 networks

A series of new 1D chain and 2D coordination polymers with cyclotriguaiacylene-type ligands are reported. A zig-zag 1D coordination chain is found in complex [Cd(2)(4ph4py)(NO(3))(3)(H(2)O)(2)(DMA)(2)]·(NO(3))·(DMA)(4), where 4ph4py = tris[4-(4-pyridyl)benzoyl]-cyclotriguaiacylene and DMA = dimethylacetamide, while complex [Zn(4ph4py)(2)(CF(3)COO)(H(2)O)]·(CF(3)COO)(NMP)(7), where NMP = N-methylpyrrolidone, has a doubly bridged coordination chain structure. Complexes [M(3ph3py)(NO(3))(2)]·(NMP)(4) where M = Co or Zn, 3ph3py = tris[3-(3-pyridyl)benzoyl]cyclotriguaiacylene, are isostructural and feature 1D ladder coordination chains. Complexes [Cd(2)(4ph4py)(2)(NO(3))(4)(NMP)]·(NMP)(9)(H(2)O)(4) and [Co(4ph4py)(H(2)O)(2)]·(NO(3))(2)·(DMF)(2), where DMF = dimethylformamide, both have (3,4)-connected 2D coordination polymers with a rare (4(2).6(2))(4.6(2))(2) topology. A 2D coordination polymer with this topology is also found in complex [Co(2)(3ph4py)(2)(NO(3))(H(2)O)(5)]·(NO(3))(3)·(DMF)(9) where 3ph4py = tris[3-(4-pyridyl)benzoyl]cyclotriguaiacylene. All 2D coordination polymer complexes are interpenetrating or polycatenating. [Co(2)(3ph4py)(2)(NO(3))(H(2)O)(5)](3+)polymers form a 2D→3D polycatenation showing self-complementary "hand-shake" interactions between the host-type ligands.     

Porous anionic, cationic, and neutral metal-carboxylate frameworks constructed from flexible tetrapodal ligands: syntheses, structures, ion-exchanges, and magnetic properties

A series of coordination polymers with anionic, cationic, and neutral metal-carboxylate frameworks have been synthesized by using a flexible tetrapodal ligand tetrakis[4-(carboxyphenyl)oxamethyl] methane acid (H(4)X). The reactions between divalent transition-metal ions and H(4)X ligands gave [M(3)X(2)]·[NH(2)(CH(3))(2)](2)·8DMA (M = Co (1), Mn (2), Cd(3)) which have anionic metal-carboxylate frameworks with NH(2)(CH(3))(2)(+) cations filled in channels. The reactions of trivalent metal ions Y(III), Dy(III), and In(III) with H(4)X ligands afforded cationic metal-carboxylate frameworks [M(3)X(2)·(NO(3))·(DMA)(2)·(H(2)O)]·5DMA·2H(2)O (M = Y(4), Dy(5)) and [In(2)X·(OH)(2)]·3DMA·6H(2)O (6) with the NO(3)(-) and OH(-) serving as counterions, respectively. Moreover, a neutral metal-carboxylate framework [Pb(2)X·(DMA)(2)]·2DMA (7) can also be isolated from reaction of Pb(II) and H(4)X ligands. The charged metal-carboxylate frameworks 1-5 have selectivity for specific counterions in the reaction system, and compounds 1 and 2 display ion-exchange behavior. Moreover, magnetic property measurements on compounds 1, 2, and 5 indicate that there exists weak antiferromagnetic interactions between magnetic centers in the three compounds.     

A 3D polar nanotubular coordination polymer with dynamic structural transformation and ferroelectric and nonlinear-optical properties

A chiral coordination nanotube, [Cd(3)(BPT)(2)(H(2)O)(9)]·2H(2)O (Cd-1; BPT = biphenyl-3,4',5-tricarboxylate), has been synthesized from achiral components and structurally characterized. It consists of homochiral channels based on right-handed helical chains and shows an interdigitated interaction to give a chiral 3D network. The chiral nanotubular framework exhibts dynamic structural transformation upon removal of the guest molecules, and the polarity of this compound induces it to display both ferroelectric and nonlinear-optical properties.     

New microporous metal-organic framework demonstrating unique selectivity for detection of high explosives and aromatic compounds

A highly luminescent three-dimensional microporous metal-organic framework, [Zn(2)(oba)(2)(bpy)]·DMA, demonstrates unique selectivity for the detection of high explosives and other aromatics via a fluorescence quenching and enhancement mechanism.     

A series of chiral coordination polymers containing helicals assembled from a new chiral (R)-2-(4'-(4'-carboxybenzyloxy)phenoxy)propanoic acid: syntheses, structures and photoluminescent properties

Ten new chiral coordination polymers, namely, [Ni(L)(H(2)O)(2)] (1), [Co(L)(H(2)O)(2)] (2), [Cd(L)(H(2)O)] (3), [Cd(L)(phen)] (4), [Mn(2)(L)(2) (phen)(2)]·H(2)O (5), [Cd(2)(L)(2)(biim-4)(2)] (6), [Zn(2)(L)(2)(biim-4)(2)] (7), [Cd(L)(pbib)] (8), [Cd(L)(bbtz)] (9) and [Cd(L)(biim-6)] (10), where phen = 1,10-phenathroline, biim-4 = 1,1'-(1,4-butanediyl)bis(imidazole), pbib = 1,4-bis(imidazole-1-ylmethyl)benzene, bbtz = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, biim-6 = 1,1'-(1,6-hexanedidyl)bis(imidazole), and H(2)L = (R)-2-(4'-(4'-carboxybenzyloxy)phenoxy)propanoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra (IR), powder X-ray diffraction (PXRD), elemental analyses and thermogravimetric (TG) analyses. Compounds 1 and 2 exhibit similar 1D left-handed helical chains, which are further extended into 3D supramolecular structures through O-H···O hydrogen-bonding interactions, respectively. Compound 3 shows a 2D double-layer architecture containing helical chains. Compound 4 features two types of 2D undulated sheets with helical chains, which are stacked in an ABAB fashion along the c direction. Compound 5 possesses a 1D double chain ribbon structure containing unusual meso-helical chains, which is linked by π-π interactions into a 2D supramolecular layer. These layers are further extended by hydrogen-bonding interactions to form a 3D supramolecular assembly. Compounds 6 and 7 are isostructural and exhibit 2D (4(4))-sql networks with helical chains. Neighboring sheets are further linked by C-H···O hydrogen-bonding interactions to generate 3D supramolecular architectures. Compounds 8-10 are isostructural and display 3D 3-fold interpenetrating diamond frameworks with helical chains. The effects of coordination modes of L anions, metal ions and N-donor ligands on the structures of the coordination polymers have been discussed. The luminescent properties of 3, 4 and 6-10 have also been investigated in detail.     

Synthesis, X-ray crystal structures, and gas sorption properties of pillared square grid nets based on paddle-wheel motifs: implications for hydrogen storage in porous materials

A systematic modulation of organic ligands connecting dinuclear paddle-wheel motifs leads to a series of isomorphous metal-organic porous materials that have a three-dimensional connectivity and interconnected pores. Aromatic dicarboxylates such as 1,4-benzenedicarboxylate (1,4-bdc), tetramethylterephthalate (tmbdc), 1,4-naphthalenedicarboxylate (1,4-ndc), tetrafluoroterephthalate (tfbdc), or 2,6-naphthalenedicarboxylate (2,6-ndc) are linear linkers that form two-dimensional layers, and diamine ligands, 4-diazabicyclo[2.2.2]octane (dabco) or 4,4'-dipyridyl (bpy), coordinate at both sides of Zn(2) paddle-wheel units to bridge the layers vertically. The resulting open frameworks [Zn(2)(1,4-bdc)(2)(dabco)] (1), [Zn(2)(1,4-bdc)(tmbdc)(dabco)] (2), [Zn(2)(tmbdc)(2)(dabco)] (3), [Zn(2)(1,4-ndc)(2)(dabco)] (4), [Zn(2)(tfbdc)(2)(dabco)] (5), and [Zn(2)(tmbdc)(2)(bpy)] (8) possess varying size of pores and free apertures originating from the side groups of the 1,4-bdc derivatives. [Zn(2)(1,4-bdc)(2)(bpy)] (6) and [Zn(2)(2,6-ndc)(2)(bpy)] (7) have two- and threefold interpenetrating structures, respectively. The non-interpenetrating frameworks (1-5 and 8) possess surface areas in the range of 1450-2090 m(2)g(-1) and hydrogen sorption capacities of 1.7-2.1 wt % at 78 K and 1 atm. A detailed analysis of the sorption data in conjunction with structural similarities and differences concludes that porous materials with straight channels and large openings do not perform better than those with wavy channels and small openings in terms of hydrogen storage through physisorption.     

Hydrothermal Synthesis and Crystal Structure of a Cadmium(Ⅱ) Polymer with One-dimensional Chain Structure: [Cd(bpy)(BDC)]n·nbpy

A metal-organic coordination polymer [Cd(bpy)(BDC)]n·nbpy (bpy = 2,2'-bipyri- dine, H2BDC = terephthalic acid) has been hydrothermally synthesized and structurally characteri- zed by elemental analysis, IR spectrum, TG and single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group C2/c with a = 15.723(5), b = 21.695(5), c = 7.576(5)(A), β = 116.171(7)o, V = 2319.3(18)(A)3, C28H20CdN4O4, Mr = 588.88, Dc = 1.686 g/cm3, μ(MoKα) = 0.987 mm(1, F(000) = 1184, Z = 4, the final R = 0.0464 and wR = 0.0831 for 1882 observed reflections (Ⅰ ＞ 2σI)). It exhibits a three-dimensional network with channels constructed from one-dimensional coordination chains via C-H…O hydrogen bonds and significant aromatic π-π stacking interactions.     

基于三联吡啶/苯三羧酸类配体构筑的两个配合物的合成、结构和性质

基于H3tbtd、H3bbta和bpy配体在水热条件下合成了配位聚合物{[Co3(tbtd)2(bpy)2(H2O)]·5H2O}n(1)和配合物[Cd2(Hbbta)(bpy)3(C2O4)(H2O)](2)(H3tbtd=4?(2,4,6?三羧基苯基)?2,2′,6′,2″?三联吡啶,H3bbta=1?氟?2,4,6?苯三酸,bpy=2,2′?联吡啶),并用元素分析、红外光谱、X射线单晶衍射等对其进行了表征。配聚物1为二维网状结构,基于丰富的氢键作用扩展形成三维超分子网结构。配合物2为双核结构,相邻的双核结构通过吡啶环之间的π…π堆积作用和氢键作用扩展为二维超分子网状结构。配聚物1在紫外光照射下对染料甲基橙(MO)的降解具有光催化活性,对紫外光催化具有良好的稳定性。此外还研究了配合物2的荧光性质和配合物1~2的热稳定性。     

Self-assembly, crystal structures, and properties of metal-2-sulfoterephthalate frameworks based on [M4(μ3-OH)2]6+ clusters (M = Co, Mn, Zn and Cd)

Hydro- and solvo-thermal reactions of d-block metal ions (Mn(2+), Co(2+), Zn(2+) and Cd(2+)) with monosodium 2-sulfoterephthalate (NaH(2)stp) form six 3D coordination polymers featuring cluster core [M(4)(μ(3)-OH)(2)](6+) in common: [M(2)(μ(3)-OH)(stp)(H(2)O)] (M = Co (1), Mn (2) and Zn (3)), [Zn(2)(μ(3)-OH)(stp)(H(2)O)(2)] (4), [Zn(4)(μ(3)-OH)(2)(stp)(2)(bpy)(2)(H(2)O)]·3.5H(2)O (5) and [Cd(2)(μ(3)-OH)(stp) (bpp)(2)]·H(2)O (6) (stp = 2-sulfoterephthalate, bpy = 4,4'-bipyridine and bpp = 1,3-di(4-pyridyl)propane). All these coordination polymers were characterized by single crystal X-ray diffraction, IR spectroscopy, thermogravimetric and elemental analysis. Complexes 1-3 are isostructural coordination polymers with 3D frameworks based on the chair-like [Zn(4)(μ(3)-OH)(2)](6+) core and the quintuple helixes. In complex 4, there exist double helixes in the 3D framework based on the chair-like cluster cores. Complex 5 possesses a 2-fold interpenetration structure constructed from boat-like cluster core and the bridging ligands stp and bpy. For complex 6, the chair-like cluster cores and stp ligands form a 2D (4,4) network which is further pillared by bpp linkers to a 3D architecture. Magnetic studies indicate that complex 1 exhibits magnetic ordering below 4.9 K with spin canting, and complex 2 shows weak antiferromagnetic coupling between the Mn(II) ions with g = 2.02, J(wb) = -2.88 cm(-1), J(bb) = -0.37 cm(-1). The fluorescence studies show that the emissions of complexes 3-6 are attributed to the ligand π-π* transition.     

Six new metal-organic frameworks based on polycarboxylate acids and V-shaped imidazole-based synthon: syntheses, crystal structures, and properties

Solvothermal reactions of 4,4'-bis(imidazol-1-yl)diphenyl ether (BIDPE) with deprotonated 5-hydroxy-isophthalic acid (5-OH-H(2)bdc), and benzene-1,3,5-tricarboxylic acid (H(3)btc) in the presence of cadmium(II), zinc(II), cobalt(II), nickel(II), and manganese(II) salts in H(2)O or H(2)O/DMF produced six new complexes, namely, [Cd(BIDPE)(5-OH-bdc)·H(2)O](n) (1), [Co(BIDPE)(5-OH-bdc)·H(2)O](n) (2), [Zn(3)(BIDPE)(3)(5-OH-bdc)(3)·4H(2)O](n) (3), [Ni(BIDPE)(2)(5-OH-bdc)(H(2)O)·3H(2)O](n) (4), {[Mn(2)(BIDPE)(2)(5-OH-bdc)(2)](n) (5), and [Ni(BIDPE)(2)(Hbtc)(H(2)O)](n) (6). These complexes were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compounds 1 and 2 reveal the same two-dimensional (2D) sheets with a 32-membered [(Cd/Co)(2)(BIDPE)(2)] metallocyclic ring constructed from BIDPE and 5-OH-H(2)bdc with Cd or Co salts. For compound 3, six identical 2D sheets are polycatenated in parallel to form a rare 2D → 2D framework; it displays ferroelectric behavior with a remnant electric polarization (P(r)) of 0.033 μC/cm(2) and an electric coercive field (E(c)) of 11.15 kV/cm. In compounds 4 and 6, only one carboxyl group coordinated to the Ni atom from 5-OH-H(2)bdc or H(3)btc. Compound 5 exists as binuclear Mn clusters, which are linked by BIDPE and 5-OH-H(2)bdc to generate a 2D sheet and displays weak antiferromagnetic character. In addition, the thermal stabilities and photochemical properties of these new complexes have been studied.     

Metal complexes as templates: syntheses, structures, and luminescent properties of two zinc phosphonocarboxylates with ABW-zeolite topology

Two novel zinc phosphonocarboxylates, Zn(3)(pbc)(2)(bpy)(H(2)O)·H(2)O (1) and Zn(2)(pbc)(2)·Zn(bpy)(H(2)O)(4)·2H(2)O (2) (pbc = 4-phosphono-benzoic acid, bpy = 2,2'-bipyridine), were hydrothermally synthesized and structurally characterized. Both of them exhibit zeolitic ABW topology in which double-zigzag inorganic chains are cross-linked by the organic parts. It is notable that the metal complex Zn(bpy)(H(2)O)(x) plays different roles in the two compounds. In 1, the Zn(bpy)(H(2)O) units coordinate with the phosphonate and carboxylate oxygen atoms and participate in the construction of the three-dimensional framework. In 2, the in situ generated [Zn(bpy)(H(2)O)(4)](2+) cation acts as a template, which directs the ABW-type open-framework by strong hydrogen bonds. It is the first example where a metal complex is used as a template in the synthesis of metal phosphonates. The luminescent properties of 1 and 2 are also investigated.     

Synthesis, structural diversity and fluorescent characterisation of a series of d10 metal-organic frameworks (MOFs): reaction conditions, secondary ligand and metal effects

Along with our recent investigation on the flexible ligand of H(2)ADA (1,3-adamantanediacetic acid), a series of Zn(II) and Cd(II) metal-organic frameworks, namely, [Zn(3)(ADA)(3)(H(2)O)(2)](n)·5nH(2)O (1), [Zn(ADA)(4,4'-bipy)(0.5)](n) (2), [Zn(2)(ADA)(2)(bpa)](n) (3), [Zn(2)(ADA)(2)(bpa)](n) (4), [Zn(2)(ADA)(2)(bpp)](n) (5), [Cd(HADA)(2)((4,4'-bipy)](n) (6), [Cd(3)(ADA)(3)(bpa)(2)(CH(3)OH)(H(2)O)](n) (7), and [Cd(2)(ADA)(2)(bpp)(2)](n)·7nH(2)O (8) have been synthesized and structurally characterized (where 4,4'-bipy = 4,4'-dipyridine, bpa = 1,2-bis(4-pyridyl)ethane and bpp = 1,3-bis(4-pyridyl)propane). Due to various coordination modes and conformations of the flexible dicarboxylate ligand and the different pyridyl-containing coligands, these complexes exhibit structural and dimensional diversity. Complex 1 exhibits a three-dimensional (3D) framework containing one-dimensional (1D) Zn(II)-O-C-O-Zn(II) clusters. Complex 2 exhibits a 2D structure constructed by 1D double chains based on [Zn(2)ADA(2)] units and a 4,4'-bipy pillar. Complexes 3 and 4 possess isomorphic 2D layer structures, resulting from the different coordination modes of carboxylate group of ADA ligands. Complex 5 features a 2D 4(4) layer in which ADA ligands and Zn(II) atoms construct a 1D looped chain and the chains are further connected by bpp ligands. Complex 6 is composed of 1D zig-zag chains that are entangled through hydrogen-bonding interactions to generate a 2D network. Complex 7 is a rare (3,5)-connected network. Complex 8 possesses a 3D microporous framework with lots of water molecules encapsulated in the channels. The structural diversity of the complexes perhaps mainly results from using diverse secondary ligands and different metal centre ions, and means the assistant ligand and metal centre play important roles in the design and synthesis of target metal-organic frameworks. This finding revealed that ADA could be used as an effective bridging ligand to construct MOFs and change coordination modes and conformational geometries in these complexes. The thermogravimetric analyses, X-ray powder diffraction and solid-state luminescent properties of the complexes have also been investigated.     

Tuning MOF Stability and Porosity via Adding Rigid Pillars

High stability and permanent porosity are the premise of general applicability for metal-organic framework materials (MOFs). By varying degrees of success on increasing the connectivity of the linear pillar 4,4'-bipyridine (bpy), two isostructural flexible frameworks [M(2)(obb)(2)(DMF)(2)]·2DMF (1, M = Zn or Cu; H(2)obb = 4,4'-oxybis(benzoic acid), DMF = N,N-dimethylformamide) with no gas sorption are structurally modified into two rigid frameworks [Zn(2)(obb)(2)(bpy)]·DMF (2) and [Cu(2)(obb)(2)(bpy)(0.5)(DMF)]·2DMF (3) with notable gas sorption and separation properties. Especially for 3, it exhibits gas selective uptake for the adsorption of CO(2) over N(2) and CH(4) under 273 K and has an interesting physically lock effect in benzene and cyclohexane sorption. The results provide a successful strategy on tuning framework stability of flexible structures via adding rigid pillars.     

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.     

Single-crystal to single-crystal transformation of 1D coordination polymer via photochemical [2+2] cycloaddition reaction

Photochemical single-crystal to single-crystal transformation of one 1D polymer [Cd(bpe)(CBA)(2)](n) afforded a new 1D polymer [Cd(rctt-tpcb)(0.5)(CBA)(2)](n) which underwent hydrothermal reaction in strong acidic solution to form a 3D coordination polymer {[Cd(rtct-tpcb)Cl(2)]·2H(2)O}(n).     

Non-interpenetrating transition metal diorganophosphate 2-dimensional rectangular grids from their 1-dimensional wires: structural transformations under mild conditions

The manganese, cobalt, and cadmium complexes [M(dtbp)2]n (M = Mn (1) and Co 2) and [Cd(dtbp)2(H2O)]n (3) (dtbp = di-tert-butyl phosphate), which exist as one-dimensional molecular wires, transform to non-interpenetrating rectangular grids [M(dtbp)2(bpy)2.2H2O]n (M = Mn (4), Co (5), and Cd (6)) by the addition of 4,4-bipyridine (bpy) at room temperature. Products 4-6 have also been prepared by a room-temperature reaction or by solvothermal synthesis in methanol through a direct reaction between the metal acetate, di-tert-butyl phosphate, and 4,4'-bipyridine (bpy) in a 1:2:2 molar ratio. Single-crystal X-ray structure determination of 4-6 shows that these compounds are composed of octahedral transition metal ions woven into a two-dimensional grid structure with the help of bpy spacer ligands. The axial coordination sites at the metal are occupied by bulky unidentate dtbp ligands, which prevent any interpenetration of the individual grids. The change of reaction conditions from solvothermal to hydrothermal, for the attempted synthesis of a magnesium grid structure, however leads to the isolation of an organic phosphate [(H2bpy)(H2PO4)2] (7) and an inorganic phosphate [Mg(HPO4)(OH2)3] (8). Compound 7 can also be prepared quantitatively from a direct reaction between bpy and H3PO4. The new organic phosphate 7 is a unique example of a phosphate material with alternating layers of [H2bpy]2+ cations and [H2PO4]- anions that are held together by hydrogen bonds. Solid-state thermal decomposition of 4-6 produced the respective metaphosphate materials [M(PO3)2] (M = Mn (9), Co (10), and Cd (11)). All new metal-organic phosphates have been characterized by elemental analysis, thermal analysis (TGA, DTA, DSC), and IR and NMR spectroscopy. The metaphosphate ceramic materials were characterized by IR spectral and powder X-ray diffraction studies.     

New Cu(II) complexes based on the hydroxo-bridged dinuclear [Cu(OH)2Cu] units: step-like di- and trimerizations of [Cu(OH)2Cu] units

Four new Cu(II) complexes {[Cu(4)(bpy)(4)(OH)(4)(H(2)O)(2)]}(NO(3))(2)(C(7)H(5)O(2))(2)·6H(2)O 1, {[Cu(4)(bpy)(4)(OH)(4)(H(2)O)(2)]}(NO(3))(2)(C(5)H(6)O(4))·8H(2)O 2, {[Cu(4)(bpy)(4)(OH)(4)(H(2)O)(2)]}(C(5)H(6)O(4))(2)·16H(2)O 3 and {[Cu(6)(bpy)(6)(OH)(6)(H(2)O)(2)]}(C(8)H(7)O(2))(6)·12H(2)O 4 were synthesized (bpy = 2,2'-bipyridine, H(2)(C(5)H(6)O(4)) = glutaric acid, H(C(7)H(5)O(2)) = benzoic acid, H(C(8)H(7)O(2)) = phenyl acetic acid). The building units in 1-3 are the tetranuclear [Cu(4)(bpy)(4)(H(2)O)(2)(μ(2)-OH)(2)(μ(3)-OH)(2)](4+) complex cations, and in 4 the hexanuclear [Cu(6)(bpy)(6)(H(2)O)(2)(μ(2)-OH)(2)(μ(3)-OH)(4)](6+) complex cations, respectively. The tetra- and hexanuclear cluster cores [Cu(4)(μ(2)-OH)(2)(μ(3)-OH)(2)] and [Cu(6)(μ(2)-OH)(2)(μ(3)-OH)(4)] in the complex cations could be viewed as from step-like di- and trimerization of the well-known hydroxo-bridged dinuclear [Cu(2)(μ(2)-OH)(2)] entities via the out-of-plane Cu-O(H) bonds. The complex cations are supramolecularly assembled into (4,4) topological networks via intercationic ππ stacking interactions. The counteranions and lattice H(2)O molecules are sandwiched between the 2D cationic networks to form hydrogen-bonded networks in 1-3, while the phenyl acetate anions and the lattice H(2)O molecules generate 3D hydrogen-bonded anionic framework to interpenetrate with the (4,4) topological cationic networks with the hexanuclear complex cations in the channels. The ferromagnetic coupling between Cu(II) ions in the [Cu(4)(μ(2)-OH)(2)(μ(3)-OH)(2)] cores of 1-3 is significantly stronger via equatorial-equatorial OH(-) bridges than via equatorial-apical ones. The outer and the central [Cu(2)(OH)(2)] unit within the [Cu(6)(μ(2)-OH)(2)(μ(3)-OH)(4)] cluster cores in 4 exhibit weak ferromagnetic and antiferromagnetic interactions, respectively. Results about i.r. spectra, thermal and elemental analyses are presented.     

Hydrothermal synthesis, structure, and luminescent properties of selected Zn(II)/Cd(II) coordination polymers constructed from 3,5-bis(x-pyridyl)-1,2,4-triazole (x = 3, 4)

Utilizing 3,5-bis(x-pyridyl)-1,2,4-triazole (x-Hpytz, x = 3; x = 4) as multidentate ligands, six novel coordination polymers with Zn(II) or Cd(II) metal ions were prepared: [Zn(3-pytz)(0.5)(OH)(0.5)Cl](n) (1, 1D ladder), {[Zn(3-Hpytz)(H(2)O)(4)] [Zn(3-Hpytz)(H(2)O)(3)·SO(4)]SO(4)·5H(2)O}(n) (2·5H(2)O, 1D chain), [Cd(3-Hpytz)(SO(4))](n) (3, 3D framework), {[Cd(3-Hyptz)SO(4)·3H(2)O]·2H(2)O}(n) (4·2H(2)O, 1D chain), [Zn(4-pytz)Cl](n) (5, 3D framework) and [Zn(2)(4-pytz)(SO(4))(OH)](n) (6, 3D framework). All compounds were obtained from hydrothermal reactions, with the exception of compound 4 which was obtained by solvent diffusion at room temperature. All compounds were characterized by FTIR, elemental analysis and TGA analysis and their structures were determined by X-ray diffraction. All compounds exhibited substantial thermal stability and showed photofluorescent properties that resulted from ligand π-π* transition.