基于1, 1′-苯乙炔-3, 3′, 5, 5′-四羧酸微孔铜配位聚合物的合成和气体吸附性质

本文报道了配合物[Cu₂(EBTC)(H₂O)₂]·8H₂O·DMF·DMSO(1, EBTC=1, 1′-乙炔基苯-3, 3′, 5, 5′-四羧酸根;DMF=N, N-二甲基甲酰胺;DMSO=二甲基亚砜)的合成、晶体结构和吸附性质。1拥有内径为0.85 nm和0.85 nm×2.15 nm的两种孔洞, 分别被6个和12个四羧酸根桥联的[Cu₂(CO₂)₄]螺旋桨式结构围绕, 并被EBTC连接成三维超分子结构, 该结构拥有可容纳溶剂分子的一维孔道。1为(3, 4)-连接的fof(sqc1575)拓扑结构, 具有非常大的孔体积, 其值高达单位晶胞体积的72.8%。去除溶剂分子后的1a表现出永久孔性, 其Langmuir表面积为2844 m²·g^-1, BET 表面积为1 852 m²·g^-1。它对H₂、CO₂、CH₄和C²H₂具有可观的气体吸附量和相对较高的吸附焓。特别是, 在迄今所有已报道的孔性金属-有机材料中, 1a在273 K、1.0×10⁵ Pa下, 表现出最高的乙炔吸附量(252 cm³·g^-1)和很高的吸附焓(吸附量为1 mmol·g^-1时的吸附焓为34.5 kJ·mol^-1)。     

基于1,1’-二苯乙炔-3,3’,5,5’-四羧酸微孔铜配位聚合物的合成和气体吸附性质

本文报道了配合物[Cu2(EBTC)(H2O)2]·8H2O·DMF.DMSO(1,EBTC=1,1′-二苯乙炔-3,3′,5,5′-四羧酸根;DMF=N,N-二甲基甲酰胺;DMSO=二甲基亚砜)的合成、晶体结构和吸附性质。1拥有内径为0.85 nm和0.85 nm×2.15 nm的两种孔洞,分别被6个和12个四羧酸根桥联的[Cu2(CO2)4]螺旋桨式结构围绕,并被EBTC连接成三维超分子结构,该结构拥有可容纳溶剂分子的一维孔道。1为(3,4)-连接的fof(sqc1575)拓扑结构,具有非常大的孔体积,其值高达单位晶胞体积的72.8%。去除溶剂分子后的1a表现出永久孔性,其Langmuir表面积为2844 m2·g-1,BET表面积为1 852 m2·g-1。它对H2、CO2、CH4和C2H2具有可观的气体吸附量和相对较高的吸附焓。特别是,在迄今所有已报道的孔性金属-有机材料中,1a在273 K、1.0×105Pa下,表现出最高的乙炔吸附量(252 cm3·g-1)和很高的吸附焓(吸附量为1 mmol·g-1时的吸附焓为34.5 kJ·mol-1)。     

5，8，5′，8′-二甲氧基-3，3′-二亚甲基-2，2′-双喹啉的合成

2-氨基-3,6-二甲氧基苯甲醛与1,2-环己二酮发生Fried lander缩合反应合成了新化合物5,8,5,′8′-二甲氧基-3,3′-二亚甲基-2,2′-双喹啉,其结构经UV,1H NMR,IR和MS表征。     

1-[2′,4′-二氟-(1,1′-联苯)-4-基苯基甲基]-咪唑的合成

以2,4-二氟联苯为起始原料,经酰化反应制得2′,4′-二氟-(1,1′-联苯)-4-基苯基甲酮(2);2经NaBH4还原得2′,4′-二氟-(1,1′-联苯)-4-基苯基甲醇(3);3经氯代得2′,4′-二氟-(1,1′-联苯)-4-基苯基氯甲烷(4);4与咪唑发生亲核取代反应合成了1-[2′,4′-二氟-(1,1′-联苯)-4-基苯基甲基]-咪唑(5). 2～5为新化合物,其结构经1H NMR, IR, MS和元素分析确证.     

由2′,4′-二氢-6′-甲氧基-3′,5′-二甲基查耳酮合成新黄酮

在DMSO/I2的氧化作用下,由2′,4′-二氢-6′-甲氧基-3′,5′-二甲基查耳酮可合成一种全新结构的黄酮:7-羟基-5-甲氧基-6,8-二甲基黄酮(产率91%),而在HCl/MeOH作用下则得到了两种黄烷酮:7-羟基-5-甲氧基-6,8-二甲基黄烷酮(产率70%)和5,7-二羟基-6,8-二甲基黄烷酮(产率20%)。     

基于1-(1′，3′-苯并噁唑-2′-甲基)苯并咪唑的钴(Ⅱ)配合物：晶体结构、弱相互作用和荧光发射光谱

配体1-(1′,3′-苯并恶唑-2′-甲基)苯并咪唑(L)是通过苯并咪唑与2-(氯甲基)-1,3-苯并恶唑烷基化制备而来。配体L与CoCl2.2H2O反应得到了配合物[CoCl2L2](1)。配合物1通过π-π堆积作用和C-H…Cl氢键形成了三维超分子框架结构。测定了L和1的荧光发射光谱。     

2,2′-二硫代二苯甲酸、2,2′-二羧苯基硫醚及含氮配体构筑的2个配合物的合成、结构与热稳定性研究(英文)

使用2,2′-二硫代二苯甲酸和2,2′-联吡啶(2,2′-bipy)、硝酸铜在水热条件下发生的原位反应合成了一个铜配合物,即[Cu2(C14H8O4S)2(C10H8N2)2](1)(C14H8O4S=2,2′-二羧苯基硫醚,C10H8N2=2,2′-联吡啶);然后又利用2,2′-二硫代二苯甲酸和菲咯啉(phen)、氯化钙在水溶液中合成了一个钙配合物,即{[Ca(C14H8O4S2)(C12H8N2)2]·(H2O)2}n(2)(C14H8O4S=2,2′-二硫代二苯甲酸根,C12H8N2=菲咯啉),并对它们分别进行了元素分析、红外光谱、热稳定性、X射线粉末衍射和X射线单晶衍射的表征。结果表明:配合物1由2,2′-二羧苯基硫醚配体连接形成了一个双核的化合物,通过氢键和氮杂环之间的π…π作用形成三维超分子网络结构。配合物2由二硫代二苯甲酸配体桥联形成了一个一维链状结构,通过氢键和氮杂环之间的π…π作用也形成三维超分子网络结构。并且,对这2个配合物的热稳定性分别进行了研究。     

含多个(R)-1,1′-联萘手性高分子合成与结构表征

单体(R)-3,3′-二碘-2,2′-二正丁氧基-1,1′-联萘((R)-M-1),(R)-6,6′-二溴-2,2′-二正丁氧基-1,1′-联萘((R)-M-2)分别与1,4-二乙烯基-2,3-二丁氧基萘(M-3),在钯催化下,通过Heck交叉耦合反应合成手性高分子P-1与P-2.单体和高分子进行了1H-NMR1、3C-NMR、FT-IR、旋光度、GPC、UV、热分析、荧光光谱和CD等测试分析.高分子侧链上引入丁氧基后使得手性高分子溶解性增强并具有良好的成膜性,手性高分子P-1和P-2都能发射较强的蓝绿色荧光,荧光量子效率分别为0.42和0.48.     

2-氯-4-氟苯甲酸与 5， 5′-二甲基-2， 2′-联吡啶镧系配合物的晶体结构、 光谱和热行为

合成并表征了2个双核配合物[Pr(2-Cl-4-FBA)₃(5,5′-DM-2,2′-bipy)]₂ (1)和[Dy(2-Cl-4-FBA)₃(5,5′-DM-2,2′-bipy)]₂·2(2-Cl-4-FHBA)(2),其中2-Cl-4-FHBA=2-氯-4-氟苯甲酸,5,5′-DM-2,2′-bipy=5,5′-二甲基-2,2′-联吡啶。配合物1以八配位的Pr³⁺为中心,其周围的配位环境为扭曲的三角十二面体。配合物2的结构是独特的,它包含2个自由的2-氯-4-氟苯甲酸分子,并以九配位的Dy³⁺为中心与周围的氮、氧原子形成扭曲的三棱镜几何构型。这2个配合物均结晶于三斜晶系P1空间群,并通过氢键相互作用和π-π堆积作用形成了一维和二维超分子结构。研究了配合物的热分解过程,结果表明配合物1和2分别分为4步和5步进行分解。同时对配合物的三维红外堆积图进行了研究,结果表明,整个热分解过程中释放出的主要气态产物是水、二氧化碳和有机小分子碎片。配合物2的荧光性质研究表明,它可以发射出Dy³⁺的特征跃迁对应的荧光。     

以3, 5-二甲基-1-羧甲基-4-吡唑甲酸为配体的两个锌的配合物的合成、晶体结构和荧光性能

以3,5-二甲基-1-羧甲基-4-吡唑甲酸和4,4′-联吡啶为配体,合成了1个单核锌(Ⅱ)配合物[Zn(4,4′-bpy)(Hcmdpca)2(H2O)3]·2H2O(1)和1个锌(Ⅱ)的一维配位聚合物[Zn(4,4′-bpy)(Hcmdpca)2(H2O)]·3H2O(2)(H2cmdpca=3,5-二甲基-1-羧甲基-4-吡唑甲酸;4,4′-bpy=4,4′-联吡啶),并用元素分析、红外光谱、X-射线单晶衍射结构分析、热重分析等对其进行了表征。配合物1和2都属于单斜晶系,空间群为P21/c。配合物1的锌离子都位于一个畸变的八面体构型中。配合物1中的独立结构单元间通过分子间氢键作用构成一个三维的超分子结构。而在2中,锌离子位于一个畸变的四方锥构型中,每个4,4′-联吡啶分子桥联2个相邻的锌(Ⅱ)离子,形成一个一维链;这些一维链和水分子通过分子间氢键进一步形成一个三维的结构。此外还考察了1和2的热稳定性和固体荧光性质。     

Three novel isomeric zinc metal-organic frameworks from a tetracarboxylate linker

Three porous supramolecular isomers (IZE-1, IZE-2, and IZE-3) with the same framework component [Zn(2)(EBTC)(H(2)O)(2)] (EBTC = 1,1'-ethynebenzene-3,3',5,5'-tetracarboxylate) were successfully constructed by finely tuning the reaction condition. Although both IZE-1 and IZE-2 are constructed from the linear EBTC subunits and one kind of regular [Zn(2)(CO(2))(4)] paddlewheels, their frameworks exhibit two different (3,4)-c net of fof (sqc1575) and sqc1572, respectively, resulting in cavities with different size and shape. However, as for isomer IZE-3, the EBTC ligands are bent and one-half of the [Zn(2)(CO(2))(4)] paddlewheels are distorted, leading to a novel (3,4,4)-c hyx net with point symbol (6.7(2))(4)(6(2).8(2).10(2))(7(2).8(2).11(2)) and vertex symbol (6.7.7)(4)(7(2).7(2).8.8.12.12)(6.6.8.8.10(2).10(2)). Quantum chemical calculations by DFT indicate that the three isomers have very close thermodynamic stabilities, which may explain that subtle condition change leads to variation of the frameworks. Further theoretical semiempirical investigation on the interactions between solvent molecules and compounds shows different hydrogen binding patterns in good agreement with the experimental observations. Furthermore, they exhibit good solid-state luminescence properties with long lifetime.     

New europium coordination polymers with efficient energy transfer from conjugated tetracarboxylate ligands to Eu3+ ion: syntheses, structures, luminescence and magnetic properties

Two novel lanthanide coordination polymers, [Eu(2)(EBTC)(DMF)(5)(NO(3))(2)]·DMF (1) and [Eu(2)(BBTC)(1.5)(CH(3)OH)(2)(H(2)O)(2)]·7DMF·HNO(3) (2) (EBTC(4-) = 1,1'-ethynebenzene-3,3',5,5'-tetracarboxylate; BBTC(4-) = 1,1'-butadiynebenzene-3,3',5,5'-tetracarboxylate), were successfully synthesized from conjugated ligands of EBTC(4-) and BBTC(4-). Although the two tetracarboxylate ligands have similar structures, their different rigidity/flexibility results in quite different networks upon complexation. Complex 1 has a two-dimensional (2-D) layered structure with two crystallographically independent Eu(3+) ions, one in a distorted monocapped square-antiprism and the other in a distorted square-antiprism coordination geometry. Complex 2 exhibits a three-dimensional (3-D) porous framework, with one type of Eu(3+) in a distorted square-antiprism and the other in a trigondodecahedron environment. Both 1 and 2 emit the intensely red characteristic luminescence of Eu(3+) ion at room temperature, with a long lifetime of up to 1.3 and 0.7 ms, respectively, during which the ligand emission of EBTC(4-)/BBTC(4-) was quenched by the Eu(3+) ion, indicating the existence of efficient energy transfer between the conjugated ligand of EBTC(4-)/BBTC(4-) and the Eu(3+) ion. Thus, both EBTC(4-) and BBTC(4-) are ideal ligands with an "antenna" effect for the Eu(3+) ion. The two complexes show the single-ion magnetic behaviors of Eu(3+) with strong spin-orbit coupling interactions even if there are shorter distances (5.714 ? for 1 versus 4.275 and 5.360 ? for 2) between the neighboring Eu(3+) ions connected by oxygen atoms of the tetracarboxylates.     

Trapping Dimethyltin Cations by Bipyridine‐N,N′‐Dioxide Ligands

N,N′‐dioxide ligands such as 2, 2′‐bipyridine‐N,N‐dioxide (BPDO‐I) and 4, 4′‐bipyridine‐N,N‐dioxide (BPDO‐II) were used to trap the hydrated dimethyltin cations under controlled hydrolysis. The use of the chelating ligand BPDO‐I leads to the isolation of the discrete monocation [Me₂Sn(BPDO‐I)(OH₂)(NO₃)]⁺[NO₃]^– ( 2 ), whereas the linear ligand BPDO‐II directs the construction of cationic polymers, [{Me₂Sn(OH₂)₂(μ‐BPDO‐II)}²⁺{NO₃^–}₂ · 2H₂O]_n ( 3· 2H₂O) and [{Me₂Sn(μ‐OH)(BPDO‐II)}₂²⁺{NO₃^–}₂ · H₂O]_n ( 4· H₂O) under different reaction conditions.     

Assemblies of a new flexible multicarboxylate ligand and d10 metal centers toward the construction of homochiral helical coordination polymers: structures, luminescence, and NLO-active properties

Hydro(solvo)thermal reactions between a new flexible multicarboxylate ligand of 2,2',3,3'-oxydiphthalic acid (2,2',3,3'-H(4)ODPA) and M(NO(3))(2).xH(2)O (M = Zn, x = 6; M = Cd, x = 4) in the presence of 4,4'-bipyridine (bpy) afford two novel homochiral helical coordination polymers [[Zn(2)(2,2',3,3'-ODPA)(bpy)(H(2)O)(3)].(H(2)O)(2) for 1 and [Cd(2)(2,2',3,3'-ODPA)(bpy)(H(2)O)(3)].(H(2)O)(2) for 2]. Though having almost the same chemical formula, they have different space groups (P2(1)2(1)2(1) for 1 and P2(1) for 2) and different bridging modes of the 2,2',3,3'-ODPA ligand. Two kinds of homochiral helices (right-handed) are found in both 1 and 2, each of which discriminates only one kind of crystallographical nonequivalent metal atom. 1 has a 2D metal-organic framework and can be seen as the unity of two parallel homochiral Zn1 and Zn2 helices, in which the nodes are etheric oxygen atoms. In contrast, 2 has a 3D metal-organic framework and consists of two partially overlapped homochiral Cd1 and Cd2 helices in the two dimensions. Moreover, metal-ODPA helices give a 2D chiral herringbone structural motif in both 1 and 2 in the two dimensions, which are further strengthened by the second ligand of bpy. Bulk materials for 1 and 2 all have good second-harmonic generation activity, approximately 1 and 0.8 times that of urea.     

An effective metallohydrolase model with a supramolecular environment: structures, properties, and activities

A supramolecular inclusion complex, [Zn(L1)(H2O)2(beta-CD)](ClO4)2.9.5 H2O (1) was synthesized and characterized structurally and its first-order active species for hydrolysis of esters, [Zn(L1)(H2O)(OH)(beta-CD)](ClO4) (2), was isolated (L1=4-(4'-tert-butylbenzyl)diethylenetriamine; beta-CD=beta-cyclodextrin). The apparent inclusion stability constant of the host and the guest measured in aqueous solution was (5.91+/-0.03)x10(3) for 1. The measured values of the first- and second-order pK(a) values of coordinated water molecules were 8.20+/-0.08 and 10.44+/-0.08, respectively, and were assigned to water molecules occupying the plane and remaining axial positions in a distorted trigonal bipyramid of the [Zn(L1)(H2O)2(beta-CD)]2+ sphere according to the structural analysis of [Zn(L2)(H2O)}2(mu-OH)](ClO4)3 (3) (L2=4-benzyldiethylenetriamine). p-Nitrophenyl acetate (pNA) hydrolysis catalyzed by 1 at pH 7.5-9.1 and 25.0+/-0.1 degrees C exhibited a first-order reaction with various concentrations of pNA and 1, but the pH profile did not indicate saturated kinetic behavior. Second-order rate constants of 0.59 and 24.0 M(-1) s(-1) were calculated for [Zn(L1)(H2O)(OH)(beta-CD)]+ and [Zn(L1)(OH)2(beta-CD)], respectively; the latter exhibited a potent catalytic activity relative to the reported mononuclear and polynuclear Zn(II) species.     

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, characterization, and structure-property relationships in two new polar oxides: Zn2(MoO4)(SeO3) and Zn2(MoO4)(TeO3)

Two new noncentrosymmetric (NCS) polar oxide materials, Zn(2)(MoO(4))(AO(3)) (A = Se(4+) or Te(4+)), have been synthesized by hydrothermal and solid-state techniques. Their crystal structures have been determined, and characterization of their functional properties (second-harmonic generation, piezoelectricity, and polarization) has been performed. The isostructural materials exhibit a three-dimensional network consisting of ZnO(4), ZnO(6), MoO(4), and AO(3) polyhedra that share edges and corners. Powder second-harmonic generation (SHG) measurements using 1064 nm radiation indicate the materials exhibit moderate SHG efficiencies of 100 × and 80 × α-SiO(2) for Zn(2)(MoO(4))(SeO(3)) and Zn(2)(MoO(4))(TeO(3)), respectively. Particle size vs SHG efficiency measurements indicate the materials are type 1 non-phase-matchable. Converse piezoelectric measurements resulted in d(33) values of ～14 and ～30 pm/V for Zn(2)(MoO(4))(SeO(3)) and Zn(2)(MoO(4))(TeO(3)), respectively, whereas pyroelectric measurements revealed coefficients of -0.31 and -0.64 μC/m(2) K at 55 °C for Zn(2)(MoO(4))(SeO(3)) and Zn(2)(MoO(4))(TeO(3)), respectively. Frequency-dependent polarization measurements confirmed that all of the materials are nonferroelectric; that is, the macroscopic polarization is not reversible, or "switchable". Infrared, UV-vis, thermogravimetric, and differential thermal analysis measurements were also performed. First-principles density functional theory (DFT) electronic structure calculations were also done. Crystal data: Zn(2)(MoO(4))(SeO(3)), monoclinic, space group P2(1) (No. 4), a = 5.1809(4) ?, b = 8.3238(7) ?, c = 7.1541(6) ?, β = 99.413(1)°, V = 305.2(1) ?(3), Z = 2; Zn(2)(MoO(4))(TeO(3)), monoclinic, space group P2(1) (No. 4), a = 5.178(4) ?, b = 8.409(6) ?, c = 7.241(5) ?, β = 99.351(8)°, V = 311.1(4) ?(3), Z = 2.     

Dinuclear zinc(II) complexes of tetraiminodiphenol macrocycles and their interactions with carboxylate anions and amino acids. Photoluminescence, equilibria, and structure

The reaction equilibria [H(4)L](2+) + Zn(OAc)(2) right harpoon over left harpoon [Zn(H(2)L)](2+) + 2HOAc (K(1)) and [Zn(H(2)L)](2+) + Zn(OAc)(2) right harpoon over left harpoon [Zn(2)L](2+) + 2HOAc (K(2)), involving zinc acetate and the perchlorate salts of the tetraiminodiphenol macrocycles [H(4)L(1)(-)(3)](ClO(4))(2), the lateral (CH(2))(n)() chains of which vary between n = 2 and n = 4, have been studied by spectrophotometric and spectrofluorimetric titrations in acetonitrile. The photoluminescence behavior of the complexes [Zn(2)L(1)](ClO(4))(2), [Zn(2)L(2)(H(2)O)(2)](ClO(4))(2), [Zn(2)L(2)(mu-O(2)CR)](ClO(4)) (R = CH(3), C(6)H(5), p-CH(3)C(6)H(4), p-OCH(3)C(6)H(4), p-ClC(6)H(4), p-NO(2)C(6)H(4)), and [Zn(2)L(3)(mu-OAc)](ClO(4)) have been investigated. The X-ray crystal structures of the complexes [Zn(2)L(2)(H(2)O)(2)](ClO(4))(2), [Zn(2)L(3)(mu-OAc)](ClO(4)), and [Zn(2)L(2)(mu-OBz)(OBz)(H(3)O)](ClO(4)) have been determined. The complex [Zn(2)L(2)(mu-OBz)(OBz)(H(3)O)](ClO(4)) in which the coordinated water molecule is present as the hydronium ion (H(3)O(+)) on deprotonation gives rise to the neutral dibenzoate-bridged compound [Zn(2)L(2)(mu-OBz)(2)].H(2)O. The equilibrium constants (K) for the reaction [Zn(2)L(2)(H(2)O)(2)](2+) + A(-) right harpoon over left harpoon [Zn(2)L(2)A](+) + 2H(2)O (K), where A(-) = acetate, benzoate, or the carboxylate moiety of the amino acids glycine, l-alanine, l-histidine, l-valine, and l-proline, have been determined spectrofluorimetrically in aqueous solution (pH 6-7) at room temperature. The binding constants (K) evaluated for these systems vary in the range (1-8) x 10(5).     

Rational construction of 3D pillared metal-organic frameworks: synthesis, structures, and hydrogen adsorption properties

In our efforts toward rational design and systematic synthesis of 'pillar-layer' structure MOFs, three porous MOFs have been constructed based on [Zn(4)(bpta)(2)(H(2)O)(2)] (H(4)bpta = 1,1'-biphenyl-2,2',6,6'-tetracarboxylic acid) layers and three different bipyridine pillar ligands. The resulted MOFs show similar structures but different pore volume and window size depending on the length of pillar ligands which resulted in distinct gas adsorption properties. In the three MOFs, [Zn(4)(bpta)(2)(4,4'-bipy)(2)(H(2)O)(2)]·(DMF)(3)·H(2)O (1) (DMF = N,N'-dimethylformamide and 4,4'-bipy = 4,4'-bipyridine) reveals selective adsorption of H(2) over N(2) and O(2) as the result of narrow pore size. [Zn(4)(bpta)(2)(azpy)(2)(H(2)O)(2)]·(DMF)(4)·(H(2)O)(3) (2) and [Zn(4)(bpta)(2)(dipytz)(2)(H(2)O)(2)]·(DMF)(4)·H(2)O (3) (azpy =4,4'-azopyridine, dipytz = di-3,6-(4-pyridyl)-1,2,4,5-tetrazine) reveal pore structure change upon different activation conditions. In addition, the samples activated under different conditions show distinct adsorption behaviors of N(2) and O(2) gases. Furthermore, hydrogen adsorption properties of activated 1-3 were studied. The results indicated that the activation process could affect the hydrogen enthalpy of adsorption.     

A series of single, double, and triple Me2biim-bridged dinuclear, trinuclear, and polymeric complexes: syntheses, crystal structures, and luminescent properties

Reaction of ZnCl(2) and Me(2)biim (Me(2)biim = N,N'-dimethyl-2,2-'-biimidazole) in acidic or neutral aqueous solutions gave the noncoordinated ZnCl(4).H(2)Me(2)biim (1) or the double Me(2)biim bridged [Zn(2)Cl(4)(mu-Me(2)biim)(2)] (2). Use of CdX(2) (X = Cl, Br, I) instead of ZnCl(2) yielded the single Me(2)biim bridged one-dimensional coordination polymer [CdX(2)(mu-Me(2)biim)](n) (X = Cl, 3; Br, 4; I, 5). The stacking of the infinite chains are dominated by C-H...X interactions in 3 and 4 but by I...I interactions in 5, responsible for their different crystal structures. Use of Zn(NO(3))(2) instead of ZnCl(2) produced the novel triple Me(2)biim-bridged [Zn(2)(mu-Me(2)biim)(3)(H(2)O)(2)](NO(3))(4).H(2)O (6). The unprecedented hexa-Me(2)bim bridged trinuclear [Cd(3)(mu-Me(2)biim)(8)](2)(ClO(4))(12)(H(2)O)(6) (7) was obtained by using Cd(CH(3)CO(2))(2) in the presence of NaClO(4). Compounds 1-7 were characterized by X-ray crystallography and IR. Examination of photophysical properties of 1-7 indicates that the fluorescence emission of Me(2)biim has been effectively enhanced, quenched, or shifted in its metal complexes 1-7.