Four octamolybdate- and Keggin-based compounds constructed by flexible bis(triazole) ligands with different spacers

Transition Metal Chemistry - By using two kinds of flexible bis(triazole) ligands 1,3-bis(1,2,4-triazol-1-y1)propane (btp) and 1,6-bis(1,2,4-triazol-1-y1)hexane (btx), four compounds based on...     

Two independent, 1-D metal–organic nanotubes based on rings or helical chain units

Three coordination polymers {[Mn(bte)(NO₂-1,3-bdc)(H₂O)]·H₂O}_n (1), {[Mn(btp)(NO₂-1,3-bdc)(H₂O)]·2H₂O}_n (2), and {[Mn(btb)(NO₂-1,3-bdc)(H₂O)]·H₂O}_n (3) (bte, 1,2-bis(1,2,4-triazol-1-yl)ethane; btp, 1,3-bis(1,2,4-triazol-1-yl)propane; btb, 1,4-bis(1,2,4-triazol-1-yl)butane, NO₂-1,3- H₂bdc, 5-nitroisophthalic acid) were synthesized by combination of bte, btp, and btb, conformationally flexible ligands with different spacer lengths, and the rigid [NO₂-1,3-bdc]^2?. In 1, two [NO₂-1,3-bdc]^2? anions link adjacent [Mn₂(bte)₂] rings to give an independent, 1-D metal–organic nanotube (MONT). The structure of 2 is an undulating 2-D (4,4) network. In 3, the combination of a [Mn(btb)]_n single helical chain and two [Mn(NO₂-1,3-bdc)]_n linear chains assemble an intriguing independent, 1-D MONT. An interesting structural feature of 1 and 3 is that the nitro groups of each 1-D MONT interpenetrate into two adjacent 1-D MONTs to form a 1-D → 2-D interdigitated array. 3-D architectures in 1 and 3 are assembled via hydrogen bond interactions. The luminescent properties and thermal stabilities of 1, 2, and 3 were investigated.     

A High Dimensional Coordination Polymer Based on [β-Mo8O26]4- Inorganic Building Block： Synthesis, Structure and Topology

A high dimensional copper coordination polymer {[Cu2(btb)2(H2O)4( -Mo8O26)] H2O}n(1, btb = 1,4-bis(1,2,4-triazol-1-yl)butane) based on [ -Mo8O26]4 anions and flexible bis(triazole) ligands has been synthesized and characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction and thermal analysis. The crystallographic data show that complex 1 crystallizes in triclinic space group P with a = 9.7550(10), b = 10.3996(11), c = 10.9516(11), = 77.622(2), = 89.602(2), = 87.610(2), V = 1084.25(19)3, C16H34Cu2Mo8 N12O31, Mr = 1785.15, Dc = 2.734 g cm 3, μ(MoKα) = 3.303 mm 1, F(000) = 856, GOF = 1.060, Z = 1, the final R = 0.0376 and wR = 0.0982 for I > 2 (I). In 1, the inorganic building block [ -Mo8O26]4 anions are connected with each other to generate one-dimensional chains. Then the chains are further connected by Cu2+ ions to form a three-dimensional (3D) inorganic framework [Cu2( -Mo8O26)]n containing quadrangular channels, with the pcu alpha-Po primitive cubic topology. The btb ligands are encapsulated into the void of the 3D inorganic framework forming a new three-dimensional architecture. The thermal analysis illustrates that complex 1 retains a comparatively good thermal stability.     

A feasible route to approach 3D POM-based hybrids: utilizing substituted or reduced Keggin anions with high charge density

Five new hybrid compounds based on Keggin polyanions, Ag(+)/Cu(+) ions and 1,3-bis(1,2,4-triazol-1-yl)propane (btp) molecules have been hydrothermally synthesized. In [Ag(5)(btp)(4)(H(2)O)(2)][PCuW(11)O(39)]·2H(2)O (1), [Ag(4.33)Na(0.67)(btp)(4)(H(2)O)(2)][PMnMo(11)O(39)]·H(2)O (2) and [Cu(4)(btp)(4)Na(H(2)O)(2)][PMnMo(11)O(39)]·2H(2)O (3), the neighboring mono-substituted Keggin clusters are alternately connected via sharing oxygen atoms to form an unusual Keggin-based transition-metal monosubstituted chain, in which the Keggin cluster serves as a decadentate ligand and grafts ten metal atoms representing the highest connected number for Keggin cluster and forming a 3D framework. In [Ag(5)(btp)(4)][PW(VI)(10)W(V)(2)O(40)] (4) and [Ag(5)(btp)(4)][PMo(VI)(10)Mo(V)(2)O(40)] (5), two-electron reduced Keggin clusters as hexadentate linkages are inserted in the rhomboid-like tunnels of the Ag-btp framework and connect with the framework via six Ag-O bonds to achieve 3D motifs, which are new and rare examples of heteropoly blue based hybrid compounds. The successful synthesis of the five high-dimensional structures may provide a feasible route for us to approach 3D polyoxometalate-based hybrids by using substituted Keggin anions and heteropoly blues with high charge density. Furthermore, photocatalytic experiments indicate that both 1 and 4 have good activities for photocatalytic degradation of RhB under UV irradiation. The luminescent properties of compounds 1-5 in the solid state were also investigated.     

(infinity)(2)[Cu2(mu5-btb)(mu-OH)(mu-H2O)]: a two-dimensional coordination polymer built from ferromagnetically coupled Cu2 units (btb = benzene-1,2,3-tricarboxylate)

Hydrothermal reaction of Cu(NO(3))(2).3H(2)O, Cd(OH)(2) or Zn(OH)(2) with benzene-1,2,3-tricarboxylic acid (H(3)btb, hemimellitic acid) produced the 2D coordination polymer (MOF) [Cu(2)(mu(5)-btb)(mu-OH)(mu-H(2)O)] () and the 2D hydrogen-bonded complexes [Cd(H(2)btb)(2)(H(2)O)(4)].2H(2)O () and [Zn(H(2)O)(6)](H(2)btb)(2).4H(2)O () which are characterized by single-crystal X-ray diffraction, X-ray powder diffraction and thermoanalysis. Magnetic susceptibility measurements between 1.9-300 K for revealed three magnetic active exchange pathways that link the copper(ii) ions through a long mu-aqua bridge, an anti-syn carboxylate bridge [j(2) = 0.161(1) cm(-1)], and through a mixed mu-hydroxo + syn-syn carboxylate bridge [J = 83(1) cm(-1)]. At temperatures higher than 30 K the system behaves as isolated Cu(2) units with strong ferromagnetic Cu-Cu coupling through the mu-hydroxo and syn-syn carboxylate bridge. The strong ferromagnetic coupling is explained with Hoffmann's approach by means of the concept of counter-complementarity introduced by Nishida et al.[Chem. Lett., 1983, 1815-1818].     

Structural evolution and magnetic properties of Co(II) coordination polymers varied from 1D to 3D constructed by 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene

Seven Co(II) coordination polymers, [Co(btx)(3)(H(2)O)(2)](ClO(4))(2)·(btx)·2H(2)O (1), [Co(btx)(3)(H(2)O)(2)](BF(4))(2)·(btx)·2H(2)O (2), [Co(btx)(2)(H(2)O)(2)](NO(3))(2)·2H(2)O (3), [Co(btx)(2)Cl(2)] (4), [Co(btx)(BA)(2)(H(2)O)(2)]·2HBA (5), [Co(btx)(IPA)] (6) and [Co(3)(btx)(3)(BTA)(2)(H(2)O)(2)] (7) (btx = (1,4-bis(1,2,4-triazol-1-ylmethyl)benzene), HBA = benzoic acid, H(2)IPA = isophthalic acid, H(3)BTA = benzene-1,3,5-tricarboxylic acid), have been hydrothermally synthesized and characterized. 1 and 2 are isostructural and show a 1D Co-μ(2)-btx-Co chain structure, in which btx acts as both a bridging and terminal ligand. 3 is also a 1D chain structure but different from 1 and 2. The Co(II) ions are bridged by double μ(2)-btx to form Co(2)-btx(2) rings, which were further connected into 1D chains by sharing the Co(II) ions of the rings. 4 exists as a 2D grid with (4,4) topology structure. When aromatic acid was introduced to the synthetic system, three other coordination polymers 5-7 were obtained. In 5, the 1D chain is as that of 1, except that the terminal ligand was replaced by BA(-). 6 shows a two-fold parallel interpenetration framework featuring a 6-c uninodal net with (3(3),4(6),5(5),6) Schlafli topological symbol. 7 is an interesting 3D framework, which contains a 2-nodal net motif with the unprecedented (3(6),4(2),5(6),6)(3(9),4(9),5(3))(2) topology structure. The influence of the varieties of the structures and magnetic properties are studied and discussed in detail.     

pH-dependent assembly of hybrids based on Wells-Dawson POM/Ag chemistry

Four new hybrids based on the Wells-Dawson polyoxometalate [P2W18O62](6-) (P2W18), ([Ag(bipy)]2[P2W18O62]).2[H2bipy].4H2O (1), ([Ag(bipy)]4[P2W18O62]).2[Hbipy](2), K[P2W18O62].2.5[H2bipy].2H2O (3), and [P2W18O62] 2.[H2bipy]4.[Hbipy]4 .3H2O (4), were hydrothermally synthesized and structurally characterized by routine techniques and single-crystal X-ray diffraction. Compounds 1 and 2 are isolated at lower pH values. 1 represents a 3D (4,4)-net structure with NbO topology, in which the P2W18 clusters are modified by four Ag-N coordination polymeric chains, and 2 exhibits a 3D (3,4)-net structure with the (9(2).12)(8.10(4).12)(3(2).10(2).11(2))(3.6.10(2).12(2)) topology, in which Ag-bipy layers are intercalated by the dimer of P2W18 clusters in a staggering mode, and the P2W18 clusters show the highest coordination number to date. By increasing the pH value, compounds 3 and 4 are obtained as supramolecular compounds. Their structural differences reveal that the pH value of the reaction system is the key factor influencing the structure and topology of these compounds, which can be explained by the acid-base chemistry of the molecular building units and silver chemistry.     

A Three-dimensional Porous Metal-organic Framework Based on Cyano Unit and 1,4-Bis（1,2,4-triazol-1-yl）butane（btb）：{[Cu_8（btb）_2（CN）_8].3H_2O}_n

The title coordination polymer 1,{[Cu8(btb)2(CN)8].3H2O}n(btb = 1,4-bis(1,2,4-triazol-1-yl)butane),has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a = 1.2938(3),b = 1.9422(5),c = 0.9406(2) nm,β = 121.891(4)°,V = 2.0066(9) nm3,C24H30Cu8N20O3,Mr = 1155.00,Dc = 1.912 g/cm3,μ(MoKα) = 4.209 mm?1,F(000) = 1140,GOF = 1.184,Z = 2,the final R = 0.0634 and wR = 0.1503 for I > 2σ(I).In complex 1,one-dimensional CuCN zigzag chains are linked by triazolyl groups of btb ligands to form two-dimensional networks,which are further bridged by 1,4-butyl moieties of btb ligands to fabricate a three-dimensional order framework,in which one-dimensional ellipsoid-like channels are observed.     

New polyoxometalate compounds built up of lacunary Wells-Dawson anions and trivalent lanthanide cations

Five new polyoxometalate compounds built on lacunary Wells-Dawson anions and trivalent lanthanide cations, KNa3[Nd2(H2O)10(alpha2-P2W17O61)].11H2O (1), (H3O)[Nd3(H2O)17(alpha2-P2W17O61)].6.75H2O (2), (H2bpy)2[Nd2(H2O)9 (alpha2-P2W17O61)].4.5H2O (3), (H2bpy)2[La2(H2O)9(alpha2-P2W17O61)].4.5H2O (4), and (H2bpy)2[Eu2(H2O)9(alpha2-P2W17O61)].5H2O (5), have been synthesized and characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction. Compound 1 shows a bisupporting polyoxometalate cluster structure where two {Nd(H2O)7}3+ fragments are supported on the polyoxometalate dimer [{Nd(H2O)3(alpha2-P2W17O61)}2]14-; this represents the first bisupporting polyoxometalate compound based on a polyoxometalate dimer. Compound 2 displays a 1D chain structure built up of bisupporting polyoxoanions [{Nd(H2O)7}2{Nd(H2O)3(alpha2-P2W17O61)}2]8- and Nd3+ ions. Compounds 3-5 are isostructural and show a 2D structure constructed of 1D polyoxometalate chains of [Ln(H2O)2(alpha2-P2W17O61)]n(7n-) linked by Ln3+ ions. Compounds 2-5 represent the first extended structures formed by lacunary Wells-Dawson anions and trivalent lanthanide ions. The influence of the Ln3+/[alpha2-P2W17O61]10- ratio on the syntheses of these five compounds has been studied. Furthermore, the fluorescent activity of compound 5 is reported.     

基于八钼酸盐杂化网络的离子热合成、晶体结构和光催化性质

采用离子热法合成了一个由八钼酸盐和过渡金属配合物构筑的新颖的三维(3D)自穿插网络的有机-无机杂化材料Cu₅^ⅠBBTZ₃H₂O[β-Mo^ⅤMo₇^ⅥO₂₆][1,BBTZ=1,4-二(三咪唑-1-乙基)苯]. 化合物1具有由3D聚圆环结构和(4,4)二维层构筑的3D自穿插框架结构. 通过单晶X射线衍射、 元素分析、 红外光谱和热重分析对化合物1的结构进行了表征, 并初步研究了其光催化产氢活性.     

基于溶剂的结构效应构筑新颖的多金属氧酸盐超分子化合物

摘要 选用不同的溶剂并在水热合成的条件下得到了二个经典Dawson型有机无机杂化的超分子化合物,即(H2BBI)3P2W18O62?H2O (1)和H2(H2BBI)2P2W18O62?2H2O (2), (BBI为1,4-二咪唑基丁烷), 通过单晶X-射线衍射、元素分析、红外光谱、光催化, 对化合物1和2的结构和性质进行了测试和表征. X-射线单晶衍射分析表明化合物1是通过多金属氧酸盐Dawson的端氧, 有机配体BBI的N原子以及游离的水分子构筑成的新颖的三维超分子结构. 化合物2是通过改变化合物1的溶剂来转变有机配体BBI在空间的排布使化合物2结晶在手性的空间群P1. 并对化合物1和2 的光催化性质进行了研究。     

Synthesis, structure and heterogeneous catalytic activities of Cu-containing polymeric compounds: anion effect and comparison of homogeneous vs. heterogeneous catalytic activity

The structures of new polymeric compounds containing Cu(II) ions and btp (2,6-bis(N'-1,2,4-triazolyl)pyridine) ligands have been determined. The btp ligands bridge Cu(II) ions to form double zigzag chains, [Cu(ClO4)2(btp)2] 3 with perchlorate anions, and form single zigzag chains, [Cu(btp)(H2O)4](SO4).2H2O 4 with sulfate anions. The polymeric compound 3 was found to effectively catalyze the epoxide ring-opening reaction with methanol, while polymeric compound 4 was almost inactive with epoxides under the same conditions. The polymeric compound 3 showed an efficient catalytic activity and regioselective reactivity in the ring opening of epoxides and allowed reuse without a significant loss of activity through three runs with epoxides.     

Synthesis,structure and electrochemical behavior of an organic-inorganic hybrid compound based on Dawson-type polyoxometalates

An organic-inorganic hybrid compound constructed from Wells-Dawson polyanion clusters and metal-organic complex subunits, [Cu(phen)₃][Cu(phen)₂Cu(phen)₂(P₂W₁₈O₆₂)]·2H₂O (1) has been prepared hydrothermally and characterized by elemental analysis, IR, UV, cyclic voltammetry (CV) and single-crystal X-ray diffraction. Crystal structural analysis indicates that two terminal oxygen atoms of the Wells-Dawson polyanion located in the “belt” site coordinate with Cu²⁺. Three Cu ions have different coordination environments: Cu1 and Cu2 are five-coordinate, while Cu3 is six-coordinate. The bisupporting polyoxoanions [Cu(phen)₂Cu(phen)₂(P₂W₁₈O₆₂)]^2? are polymerized into a 1D chain by hydrogen bonding interactions, then the chains are stacked into a two-dimensional structure via offset, face-to-face, π ··· π stacking interactions. CV reveals that 1 exhibits three chemically-reversible processes.     

Two Novel 3D Wells–Dawson Based Coordination Polymers with Unusual Topological Structure Extended by 1,4-Bis(1,2,4-triazol-1-yl)butane

Two novel Wells–Dawson based coordination polymers, [Co₂(btb)₄(H₂O)][H₂X₂W₁₈O₆₂]·nH₂O (X = P for 1 and As for 2; n = 3 for 1 and 6 for 2) (btb = 1,4-bis(1,2,4-triazol-1-y1)butane), have been successfully isolated under hydrothermal conditions. Single crystal X-ray diffraction analyses reveal that isostructural compounds 1 and 2 exhibit 2D metal–organic layers, which are further linked by four-dentate [X₂W₁₈O₆₂]^6? anions to form an unusual (4,4,6)-connected self-penetrating 3D framework with the Schläfli symbol of {3·5·6⁴}{3²·5²·6⁶·7³·8²}{5²·6⁴}. To the best of our knowledge, this kind of topological structure has not been reported yet. The electrochemical and photocatalytic properties of compounds 1 and 2 have been investigated.     

Copper(II) coordination polymers constructed from aromatic polycarboxylate and flexible triazole ligands with different spacer lengths: syntheses,structures, and properties

{[Cu₂(btm)₂(Hbtc)(H₂btc)₂(H₂O)]·9.5H₂O}_n (1), [Cu(bte)(H₂btc)₂]_n (2) {[Cu(btp)(H₂btc)₂]·0.25H₂O}_n (3) (btm?=?bis(1,2,4-triazol-1-yl)methane, bte?=?bis(1,2,4-triazol-1-yl)ethane, btp?=?bis(1,2,4-triazol-1-yl)propane, H₃btc?=?benzene-1, 3, 5-tricarboxylic acid) have been synthesized and structurally characterized. 1 features a 1-D double chain, which is interconnected by classical hydrogen-bonding (O–H?O) and π–π interactions to lead to a 3-D supramolecular architecture. 2 and 3 are both 1-D single chains, which are interconnected by π–π interactions to 2-D layer architectures. Elemental analysis, XRD, IR, TG and EPR spectra have been carried out and discussed.     

Syntheses and structures of organic-inorganic hybrid compounds based on metal-fluconazole coordination polymers and the beta-Mo8O26 anion

Five organic-inorganic hybrid compounds, namely, [Co2(fcz)4(H2O)4][beta-Mo8O26].5H2O (1), [Ni2(fcz)4(H2O)4][beta-Mo8O26].5H2O (2), [Zn2(fcz)4(beta-Mo8O26)].4H2O (3), [Cu2(fcz)4(beta-Mo8O26)].4H2O (4), and [Ag4(fcz)4(beta-Mo8O26)] (5), where fcz is fluconazole [2-(2,4-difluorophenyl)-1,3-di(1H-1,2,4-triazol-1-yl)propan-2-ol], were synthesized under hydrothermal conditions, and crystal structures of 1-5 have been determined by X-ray diffraction. In compounds 1 and 2, metal cations are linked by fluconazole ligands to form hinged chain structures and [beta-Mo8O26]4- anions act as counterions. In compound 3, Zn(II) cations are bridged by fluconazole ligands to form 2D (4,4) networks, and each pair of these networks is linked by [beta-Mo8O26]4- anions to form a sandwich double-layer structure. In compound 4, Cu(II) cations are bridged by fluconazole ligands to form 2D (4,4) networks, and these networks are connected by [beta-Mo8O26]4- anions to form a 3D framework. In compound 5, AgI cations and [Ag2]2+ units are bridged by fluconazole ligands to form 2D Ag-fcz layers, and these layers are further connected by [beta-Mo8O26]4- anions to form a complicated 3D structure with the topology of (7(2).8(1))2(7(3).8(3))(7(2).8(11).10(1).12(1))2. Thermogravimetric analyses for these compounds are also discussed in detail. The complexes exhibit antitumor activity in vitro, as shown by MTT experiments.     

三缺位Keggin多阴离子[α-A-AsW_9O_（34）]~（9-）到Dawson多阴离子[α-As_2W_（18）O_（62）]~（6-）的结构转变（英文）

以Na8[α-A-HAsW9O34].11H2O,CuCl2.2H2O和乙二胺（en）为原料,在两步水热条件下反应合成了一种有机-无机复合的饱和Dawson砷钨酸盐[H2en]3[α-As2W18O62].0.5en.9H2O（1）,并对其进行了元素分析、红外光谱和单晶X射线衍射表征。在化合物1的形成过程中,首次观察到三缺位Keggin多阴离子[α-A-AsW9O34]9-到饱和Dawson多阴离子[α-As2W18O62]6-的结构转变,这为饱和Dawson多阴离子可以看作由两个三缺位Keggin多阴离子通过共用六个氧原子聚合而成的事实提供了一个有力的实验证据。而且,多金属氧酸盐化学中其它一些不同多阴离子间的转变也被归纳。     

1,2,4-Triazole functionalized adamantanes: a new library of polydentate tectons for designing structures of coordination polymers

A series of functionalized adamantanes: 1,3-bis(1,2,4-triazol-4-yl)(tr(2)ad); 1,3,5-tris(1,2,4-triazol-4-yl)-(tr(3)ad); 1,3,5,7-tetrakis(1,2,4-triazol-4-yl)adamantanes (tr(4)ad) and 3,5,7-tris(1,2,4-triazol-4-yl)-1-azaadamantane (tr(3)ada) were developed as a new family of geometrically rigid polydentate tectons for supramolecular synthesis of framework solids. The coordination compounds were prepared under hydrothermal conditions; their structures reveal a special potential of the triazolyl adamantanes for the generation of highly-connected and open frameworks as well as structures based upon polynuclear metal clusters assembled with short-distance N(1),N(2)-triazole bridges. Complexes [Cd{L}(2)]A·nH(2)O [L = tr(3)ad, A = 2NO(3)(-) (4), CdCl(4)(2-) (5); L = tr(3)ada, A = CdI(4)(2-) (7)] are isomorphous and adopt a layered 3,6-connected structure of CdI(2) type. [{Cu(3)(OH)}(2)(SO(4))(5)(H(2)O)(2){tr(3)ad}(3)]·26H(2)O (6) is a layered polymer based upon Cu(3)(μ(3)-OH) nodes and trigonal tr(3)ad links. In [Cu(3)(OH)(2){tr(3)ada}(2)(H(2)O)(4)](ClO(4))(4) (8), [Cu(2){tr(3)ada}(2)(H(2)O)(3)](SO(4))(2)·7H(2)O (9) and [Cd(2){tr(3)ada}(3)]Cl(4)·28H(2)O (10) (UCl(3)-type net) the organic tripodal ligands bridge polynuclear metal clusters. Complexes [Ag{tr(4)ad}]NO(3)·3.5H(2)O (11) and [Cu{tr(4)ad}(H(2)O)](ClO(4))(2)·3H(2)O (12) have 3D SrAl(2)-type frameworks with the metal ions and adamantane tectons as topologically equivalent tetrahedral nodes, while in [Cd(3)Cl(6){tr(4)ad}(2)]·9H(2)O (13) the ligands bridge trinuclear six-connected Cd(3)Cl(6)(μ-tr)(4)(tr)(2) clusters. In the compounds [Cd(2){tr(2)ad}(4)(H(2)O)(4)](CdBr(4))(2)·2H(2)O (2) and [Cd{tr(2)ad}(4){CdI(3)}(2)]·4H(2)O (3) the bitopic ligands provide simple links between the metal ions, while in [Ag(2){tr(2)ad}(2)](NO(3))(2)·2H(2)O (1) the ligand is tetradentate and generates a 3D framework.     

Supramolecular isomers in the same crystal: a new type of entanglement involving ribbons of rings and 2D (4,4) networks polycatenated in a 3D architecture

The reaction of corresponding cadmium salts with the flexible ligand 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene (bbtz) affords the 3D coordination network [Cd3(bbtz)6(H2O)6](BF4)(6.1.75H2O (1), containing ribbons of rings and planar 2D (4,4) networks polycatenated with each other, the undulating 2D (4,4) network [Cd(bbtz)2(H2O)2](ClO4)2.2H2O (2), and ribbons of rings [Cd(bbtz)2(H2O)2](BF4)2.3DMF (3) and [Cd(bbtz)2(H2O)2](ClO4)2.3DMF (4).     

Ag(I)/V(V) Heterobimetallic Frameworks Generated from Novel-Type {Ag(2)(VO(2)F(2))(2)(triazole)(4)} Secondary Building Blocks: A New Aspect in the Design of SVOF Hybrids

A series of new silver(I)-containing MOFs [Ag(2)(tr(2)ad)(2)](ClO(4))(2) (1), [Ag(2)(VO(2)F(2))(2)(tr(2)ad)(2)]·H(2)O (2), [Ag(2)(VO(2)F(2))(2)(tr(2)eth)(2)(H(2)O)(2)] (3), and [Ag(2)(VO(2)F(2))(2)(tr(2)cy)(2)]·4H(2)O (4) supported by 4-substituted bifunctional 1,2,4-triazole ligands (tr(2)ad = 1,3-bis(1,2,4-triazol-4-yl)adamantane, tr(2)eth = 1,2-bis(1,2,4-triazol-4-yl)ethane, tr(2)cy = trans-1,4-bis(1,2,4-triazol-4-yl)cyclohexane) were hydrothermally synthesized and structurally characterized. In these complexes, the triazole heterocycle as an N(1),N(2)-bridge links either two adjacent Ag-Ag or Ag-V centers at short distances forming polynuclear clusters. The crystal structure of compound 1 is based on cationic {Ag(2)(tr)(4)}(2+) fragments connected in a 2D rhombohedral grid network with (4,4) topology. The neighboring layers are tightly packed into a 3D array by means of argentophilic interactions (Ag···Ag 3.28 ?). Bridging between different metal atoms through the triazole groups assists formation of heterobimetallic Ag(I)/V(V) secondary building blocks in a linear V-Ag-Ag-V sequence that is observed in complexes 2-4. These unprecedented tetranuclear {Ag(2)(VO(2)F(2))(2)(tr)(4)} units (the intermetal Ag-Ag and Ag-V distances are 4.24-4.36 and 3.74-3.81 ?, respectively), in which vanadium(V) oxofluoride units possess distorted trigonal bipyramidal environment {VO(2)F(2)N}ˉ, are incorporated into 1D ribbon (2) or 2D square nets (3, 4) using bitopic μ(4)-triazole ligands. The valence bond calculation for vanadium atoms shows +V oxidation state in the corresponding compounds. Thermal stability and photoluminescence properties were studied for all reported coordination polymers.