Cd(2+) Complexation with P(CH(2)OH)(3), OP(CH(2)OH)(3), and (HOCH(2))(2)PO(2)(-): Coordination in Solution and Coordination Polymers

The coordination of Cd(2+) with P(CH(2)OH)(3) (THP) in methanol was followed by (31)P and (111)Cd NMR techniques. A cadmium-to-phosphine coordination ratio of 1:3 has been established, and effective kinetic parameters have been calculated. Air oxidation of THP in the presence of CdCl(2) at room temperature produces coordination polymer (3)(∞)[Cd(3)Cl(6)(OP(CH(2)OH)(3))(2)] (1). The same oxidation reaction at 70 °C gives another coordination polymer, (∞)[CdCl(2)(OP(CH(2)OH)(3))] (2). Complexes 1 and 2 are the first structurally characterized complexes featuring OP(CH(2)OH)(3) as a ligand that acts as a linker between Cd atoms. The addition of NaBPh(4) to the reaction mixture gives coordination polymer (∞)[Na(2)CdCl(2)(O(2)P(CH(2)OH)(2))(2)(H(2)O)(3)] (3) with (HOCH(2))(2)PO(2)(-) as the ligand. Coordination polymers 1-3 have been characterized by X-ray analysis, elemental analysis, and IR spectroscopy.     

Isolation and crystallographic characterization of a solid precipitate/intermediate in the preparation of 5-substituted 1H-tetrazoles from nitrile in water

The reactions of 2-, 3-, and 4-cyanopyridine with NaN(3) in the presence of H(2)O and Lewis acid (ZnCl(2)) afford discrete monomer, (2-PTZ)(2)Zn(H(2)O)(2) (1), 3D diamondoid-like network (3-PTZ)(2)Zn (2), and 2D layered network (4-PTZ)Zn(OH)(H(2)O) (3), respectively (PTZ = 5-(pyridyl)tetrazolato). Their solid state structures and natures give new insight into the Sharpless reaction of 5-substituted 1H-tetrazole. Interestingly, 2 crystallizes in a noncentrosymmetric space group and its powdered sample is second-harmonic generation active.     

Chemistry of a binuclear cadmium(II) hydroxide complex: formation from water,CO(2) reactivity,and comparison to a zinc analog

Treatment of the bmnpa (N,N-bis-2-(methylthio)ethyl-N-((6-neopentylamino-2-pyridyl)methyl)amine) ligand with equimolar amounts of Cd(ClO(4))(2).5H(2)O and Me(4)NOH.5H(2)O in CH(3)CN yielded the binuclear cadmium hydroxide complex [((bmnpa)Cd)(2)(mu-OH)(2)](ClO(4))(2).CH(3)CN (1). Complex 1 may also be prepared (a) by treatment of a CH(3)CN solution of (bmnpa)Cd(ClO(4))(2) (2) with 1 equiv of n-BuLi, followed by treatment with water or (b) from 2 in the presence of 1 equiv each of water and NEt(3). The hydroxide derivative 1 is not produced from 2 and water in the absence of an added base. Complex 1 possesses a binuclear structure in the solid state with hydrogen-bonding and CH/pi interactions involving the bmnpa ligand. The overall structural features of 1 differ from the halide derivative [((bmnpa)Cd)(2)(mu-Cl)(2)](ClO(4))(2) (3), particularly in that the Cd(2)(mu-OH)(2) core of 1 is symmetric whereas the Cd(2)(mu-Cl)(2) core of 3 is asymmetric. In acetonitrile solution, 1 behaves as a 1:2 electrolyte and retains a binuclear structure and secondary hydrogen-bonding and CH/pi interactions, whereas 3 is a 1:1 electrolyte, indicating formation of a mononuclear [(bmnpa)CdCl]ClO(4) species in solution. Treatment of 1 with CO(2) in anhydrous CH(3)CN yields the bridging carbonate complex [((bmnpa)Cd)(2)(mu-CO(3))](ClO(4))(2).CH(3)CN (4). Treatment of a chemically similar zinc hydroxide complex, [((benpa)Zn)(2)(mu-OH)(2)](ClO(4))(2) (benpa = N,N-bis-2-(ethylthio)ethyl-N-((6-neopentylamino-2-pyridyl)methyl)amine, with CO(2) also results in the formation of a carbonate derivative, [((benpa)Zn)(2)(mu-CO(3))](ClO(4))(2) (5), albeit the coordination mode of the bridging carbonate moiety is different. Treatment of 4 with added water results in no reaction, whereas 5 under identical conditions will undergo reaction to yield the zinc hydroxide complex [((benpa)Zn)(2)(mu-OH)(2)](ClO(4))(2).     

Syntheses, structural characterization and properties of transition metal complexes of 5,5'-(1,4-phenylene)bis(1H-tetrazole) (H(2)bdt), 5',5'-(1,1'-biphenyl)-4,4'-diylbis(1H-tetrazole) (H(2)dbdt) and 5,5',5'-(1,3,5-phenylene)tris(1H-tetrazole) (H(3)btt)

The hydrothermal chemistry of a variety of M(II)SO(4) salts with the tetrazole (Ht) ligands 5,5'-(1,4-phenylene)bis(1H-tetrazole) (H(2)bdt), 5',5'-(1,1'-biphenyl)4,4'-diylbis(1H-tetrazole) (H(2)dbdt) and 5,5',5'-(1,3,5-phenylene)tris(1H-tetrazole) (H(3)btt) was investigated. In the case of Co(II), three phases were isolated, two of which incorporated sulfate: [Co(5)F(2)(dbdt)(4)(H(2)O)(6)]·2H(2)O (1·2H(2)O), [Co(4)(OH)(2)(SO(4))(bdt)(2)(H(2)O)(4)] (2) and [Co(3)(OH)(SO(4))(btt)(H(2)O)(4)]·3H(2)O (3·3H(2)O). The structures are three-dimensional and consist of cluster-based secondary building units: the pentanuclear {Co(5)F(2)(tetrazolate)(8)(H(2)O)(6)}, the tetranuclear {Co(4)(OH)(2)(SO(4))(2)(tetrazolate)(6)}(4-), and the trinuclear {Co(3)(μ(3)-OH)(SO(4))(2) (tetrazolate)(3)}(2-) for 1, 2, and 3, respectively. The Ni(II) analogue [Ni(2)(H(0.67)bdt)(3)]·10.5H(2)O (4·10.5H(2)O) is isomorphous with a fourth cobalt phase, the previously reported [Co(2)(H(0.67)bat)(3)]·20H(2)O and exhibits a {M(tetrazolate)(3/2)}(∞) chain as the fundamental building block. The dense three-dimensional structure of [Zn(bdt)] (5) consists of {ZnN(4)}tetrahedra linked through bdt ligands bonding through N1,N3 donors at either tetrazolate terminus. In contrast to the hydrothermal synthesis of 1-5, the Cd(II) material (Me(2)NH(2))(3)[Cd(12)Cl(3)(btt)(8)(DMF)(12)]·xDMF·yMeOH (DMF = dimethylformamide; x = ca. 12, y = ca. 5) was prepared in DMF/methanol. The structure is constructed from the linking of {Cd(4)Cl(tetrazolate)(8)(DMF)(4)}(1-) secondary building units to produce an open-framework material exhibiting 66.5% void volume. The magnetic properties of the Co(II) series are reflective of the structural building units.     

New metal complexes with di(mono)acylhydrazidate molecules

The simple hydrothermal self-assemblies between metal salts, organic polycarboxylic acids and N(2)H(4)·H(2)O, sometimes in the presence of phenanthroline (phen), created four di(mono)acylhydrazidate-coordinated compounds [Pb(2)(DPHKH)(2)(phen)(2)]·2H(2)O 1, [Cd(ODPTH)(phen)]·0.25H(2)O 2, [Pb(2)(MPTH)(4)(phen)(2)] 3, [Cd(2)(MPTH)(4)(phen)(2)]·H(2)O 4 as well as one diacylhydrazide molecule [H(2)(ODPTH)] 5 (DPHKH = 4,4'-diphthalhydrazidatoketone hydrazone, MPTH = 3-methylphthalhydrazidate, ODPTH = 4,4'-oxydiphthalhydrazidate). Note that the di(mono)acylhydrazidate molecules in the title compounds originated from the in situ acylation reactions between organic polycarboxylic acids and N(2)H(4)·H(2)O. Interestingly, another kind of ligand in situ reaction was found in the formation process of DPHKH in compound 1: the nucleophilic addition reaction of a ketone with N(2)H(4)·H(2)O.     

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.     

Porous Cu-Cd mixed-metal-organic frameworks constructed from Cu(Pyac)2 [Bis[3-(4-pyridyl)pentane-2,4-dionato]copper(II)

Porous Cu-Cd mixed-metal-organic frameworks [[Cd(NO(3))(2)](2)[(Cu(Pyac)(2)](3)] (M'MOF 1) and [[CdCl(2)][Cu(Pyac)(2)](2)] (M'MOF2) [Cu(Pyac)(2) = bis[3-(4-pyridyl)pentane-2,4-dionato]copper(II)] have been synthesized by the reaction of Cu(Pyac)(2) with Cd(NO(3))(2) and CdCl(2). They are noninterpenetrating 1D ladder and 2D square-grid frameworks, constructed from Cu(Pyac)(2) building blocks with T-shaped Cd(NO(3))(2) nodes and square-planar CdCl(2) nodes, respectively. The 1D ladders and 2D square grids are stacked in ABCABC... and ABCDEF... packings, leading to 2D interconnected channels of ca. 5.7 x 10.2 and 4.1 x 9.8 A in 1 and 1D channels of ca. 8.0 x 8.2 A in 2, respectively. The copper sites in these two M'MOFs are coordinated by solvent molecules and exposed to the pores.     

Synthesis of a series of 4-pyridyl-1,2,4-triazole-containing cadmium(II) luminescent complexes

Using two 4-substitued triazole ligands, 4-(pyrid-2-yl)-1,2,4-triazole (L(1)) and 4-(pyrid-3-yl)-1,2,4-triazole (L(2)), a series of novel triazole-cadmium(II) complexes varying from zero- to three-dimensional have been prepared and their crystal structures determined via single-crystal X-ray diffraction. [Cd(2)(micro(2)-L(1))(3)(L(1))(2)(NO(3))(mu(2)-NO(3))(H(2)O)(2)](NO(3))(2).1.75H(2)O (1) is a binuclear complex containing bidendate, monodedate and free nitrate anions. When the bridging anions SCN(-) and dca (dca = N(CN)(2)(-)) were added to the reaction system of 1, one-dimensional (1D) [Cd(L(1))(2)(NCS)(2)](n) (2) and two-dimensional (2D) [Cd(L(1))(2)(dca)(2)](n) (3) were isolated, respectively. When L(2) instead of L(1) was used, [Cd(L(2))(2)(NCS)(2)(H(2)O)(2)] (4) and 1D [Cd(L(2))(2)(dca)(2)](n) (5) were obtained. When the ratio of Cd to L(2) was changed from 1:2 to 1:1 in the reaction system of 5, three-dimensional (3D) {[Cd(3)(micro(2)-L(2))(3)(dca)(6)].0.75H(2)O}(n) (6) with 1D microporous channels along the a direction was isolated. Further investigations on other Cd(ii) salts and the L(2) ligand in a Cd to L(2) ratio of 1:1, an unexpected complex [Cd(mu(2)-L(2))(mu(3)-SO(4))(H(2)O)](n) (7) with a 3D open framework was obtained. All of the complexes exhibit strong blue fluorescence emission bands in the solid state at ambient temperature, of which the excitation and emission maxima are red-shifted to longer wavelength as compared to those in water. Powder X-ray diffraction and thermal studies were used to investigate the bulk nature of the 3D coordination polymers 6 and 7.     

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.     

Hydrothermal syntheses, crystal structures, and characteristics of a series of Cd-btx coordination polymers (btx = 1,4-Bis(triazol-1-ylmethyl)benzene)

Four novel cadmium-btx (btx = 1,4-bis(triazol-1-ylmethyl)benzene) coordination polymers [Cd(btx)(2)(NO(3))(2)](n)(1), [Cd(btx)(2)Cl(2)](n)(2), [Cd(btx)(SO(4))(H(2)O)(2)](n)(3), and [Cd(btx)(S(2)O(7))(H(2)O)](n)(4) have been prepared by hydrothermal reaction (140 or 180 degrees C) and characterized. Both 1 and 2 have two-dimensional rhombohedral grid structures, 3 possesses a two-dimensional rectangular grid structure, and 4 displays a three-dimensional framework, which is formed by btx bridging parallel layers. To the author's best knowledge, polymer 4 is the first Cd(II) polymer in which the Cd(II) ion is eight-coordinated in a hexagonal bipyrimidal geometry. In addition, we studied the effects of temperature on the hydrothermal reaction system of btx and CdSO(4) and found that different products can be obtained at different temperatures. Furthermore, polymer 3 possesses a very strong third-order NLO absorptive effect with an alpha(2) value of 1.15 x 10(-)(9) m W(-1). Polymers 2-4 display strong fluorescent emissions in the solid state at room temperature. The DTA and TGA results of the four polymers are in agreement with the crystal structures.     

High-nuclearity metal-organic nanospheres: a Cd66 ball

Reaction of H(3)L with Cd(NO(3))(2)·4H(2)O in DMF at 150 °C for 3 days affords the metal-organic nanosphere [Cd(66)(μ(3)-OH)(28)(μ(3)-O)(16)(μ(5)-NO(3)-O,O,O',O',O″,O″)(12)(L)(20)(μ(2)-DMF)(12)?(DMF)(9)]. The cluster is composed of a spherical shell of 66 Cd(II) cations bridged by 28 μ(3)-hydroxide, 16 μ(3)-oxo, and five μ(5)-NO(3)(-) anions surrounded by a shell of 20 tripodal capping ligands (L) and 12 DMF ligands. The 66 Cd(II) cations and 12 NO(3)(-) anions form a polydeltahedron that has 78 vertices [Cd(II) or NO(3)(-)] (V), 228 edges (E), and 152 triangular faces (F), giving it an Euler characteristic (χ) of 2 (χ = V + F - E). Reaction of H(3)L with Cd(NO(3))(2)·4H(2)O at lower temperatures or with CdCl(2) affords coordination polymer frameworks instead of nanospheres.     

Reactions of cadmium(II) nitrate with 4-(trimethylammonio)benzenethiolate in the presence of N-donor ligands

Reactions of Cd(NO(3))(2)·4H(2)O with TabHPF(6) (TabH = 4-(trimethylammonio)benzenethiol) and Et(3)N in the presence of NH(4)SCN and five other N-donor ligands such as 2,2'-bipyridine (2,2'-bipy), phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (2,9-dmphen), 2,6-bis(pyrazd-3-yl)pyridine (bppy) and 2,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)pyridine (bdmppy) gave rise to a family of Cd(II)/thiolate complexes of N-donor ligands, {[Cd(2)(μ-Tab)(4)(NCS)(2)](NO(3))(2)·MeOH}(n) (1), [Cd(2)(μ-Tab)(2)(L)(4)](PF(6))(4) (2: L = 2,2'-bipy; 3: L = phen), [Cd(Tab)(2)(L)](PF(6))(2) (4: L = 2,9-dmphen; 5: L = bppy), and [Cd(2)(μ-Tab)(2)(Tab)(2)(bdmppy)](2)(PF(6))(8)·H(2)O (6·H(2)O). These compounds were characterized by elemental analysis, IR spectra, UV-Vis spectra, (1)H NMR, electrospray ionization (ESI) mass spectra and single-crystal X-ray diffraction. For 1, each [Cd(NCS)](+) fragment is connected to its equivalents via a pair of Tab bridges to a one-dimensional chain. For 2 and 3, two [Cd(2,2'-bipy)(2)](2+) or [Cd(phen)(2)](2+) units are linked by a pair of Tab bridges to form a cationic dimeric structure. The Cd atom in [Cd(Tab)(2)(L)](2+) dication of 4 or 5 is coordinated by two Tab ligands and chelated by two N atoms from 2,9-dmphen (4) or three N atoms from bppy (5), forming a distorted tetrahedral (4) or trigonal bipyramidal (5) coordination geometry. For 6, each of two [Cd(Tab)(bdmppy)] fragments is linked to one [(Tab)Cd(μ-Tab)(2)Cd(Tab)] fragment via two Tab bridges to generate a unique cationic zigzag tetrameric structure where the Cd centers take a tetrahedral or a trigonal bipyramidal coordination geometry. The results may provide an interesting insight into mimicking the coordination spheres of the Cd(II) sites of metallothioneins and their interactions with various N-donor ligands encountered in nature.     

Flexible ligands and structural diversity: isomerism in Cd(NO3)2 coordination polymers

The ligands 1,4-bis(2-pyridylmethylsulfanylmethyl)benzene (L1) and 2,5-bis(2-pyridylmethylsulfanylmethyl)pyrazine (L2) were treated with Cd(NO3)2.4H2O in metal-to-ligand ratios of 1:1 and 2:1, respectively; L2 was also treated with CdCl2.2.5H2O in a 2:1 ratio. All products were found to be coordination polymers. The crystal structures of {[Cd(L1)(NO3)2].CH2Cl2}infinity (1a), {[Cd(L1)(NO3)2].4/3CH3CN}infinity (1b), {[Cd2(L2)(NO3)4].2CH3CN}infinity (2.2CH3CN), and {[Cd2(L2)Cl4].2CH2Cl2}infinity (3.2CH2Cl2) were determined. Compounds 1a and 1b were found to be conformational supramolecular isomers. The structure of 1b displayed topological isomerism with two isomeric polymer chains, 1b(1) and 1b(2), in the one crystal forming a single supramolecular array. The structure of 2.2CH(3)CN showed Cd2(L2) units linked together by nitrates bridging between the Cd(II) centers in a mode previously not seen in Cd(II) compounds. The overall structure of 3.2CH2Cl2 was found to be similar to that of 2.2CH3CN despite the presence of different anions and solvent molecules. Powder X-ray diffraction was used to investigate the nature of bulk preparations of compounds 1-3.     

由MCl2(M=Zn，Cd)与咪唑-4，5-二羧酸和1，4-双(咪唑-1-基)丁烷构筑的两个二重穿插二维配位聚合物的合成、结构和性质

以2∶1∶4物质的量比的咪唑-4,5-二羧酸(H3IDC),1,4-双(咪唑-1-基)丁烷(bib)和ZnCl2或CdCl2为反应物,在水热条件下分别得到了1个二重穿插的二维锌(Ⅱ)配位聚合物{[Zn2(IDC)(bib)Cl].H2O}n(1)和1个二重穿插的二维镉(Ⅱ)配位聚合物[Cd2(HIDC)(bib)1.5Cl2]n(2)。用元素分析、红外光谱以及单晶X-射线衍射结构分析对它们的组成和结构进行了表征,并对它们的热稳定性和荧光性质进行了初步的研究。     

Controlled binding of a L-cysteinato cobalt(III) octahedron to a cadmium(II) center

The binding ability of a chiral L-cysteinato cobalt(III) complex, [Co(L-cys-N,S)(en)2]+ (l-H2cys = L-cysteine, en = ethylenediamine), toward a cadmium(II) center, together with the construction of S-bridged CoIIICdII structures that are controlled by anions and pH, is reported. The reaction of Lambda(L)-[Co(L-Hcys-N,S)(en)2](ClO4)2 having a pendent COOH group with CdCl2 in a 1:1 ratio in water, followed by the addition of NaCl, gave an S-bridged CoIIICdII dinuclear complex, Lambda(L)-[CdCl4{Co(L-Hcys-N,S)(en)2}] (1Cl), in which a cadmium(II) ion is weakly coordinated by a thiolato group from a Lambda(L)-[Co(L-Hcys-N,S)(en)2]2+ unit, besides four Cl- anions. The corresponding 1:1 reaction with CdBr2 and NaBr yielded an S-bridged CoIIICdIICoIII trinuclear complex composed of an S-bridged CoIIICdIICoIII trinuclear cation and a [CdBr4]2- anion, (Lambda(L))2-[CdBr3{Co(L-Hcys-N,S)(en)2}{Co(L-cys-N,S)(en)2} ][CdBr4] (2), while a CoIIICdII dinuclear complex analogous to 1Cl, Lambda(L)-[CdBr4{Co(L-Hcys-N,S)(en)2}] (1Br), was obtained by the addition of HBr instead of NaBr. In the CoIIICdIICoIII cation of 2, a CdII center is very weakly coordinated by two thiolato groups from Lambda(L)-[Co(L-Hcys-N,S)(en)2]2+ and Lambda(L)-[Co(L-cys-N,S)(en)2]+ units, besides three Br- anions, with the trinuclear structure being sustained by an intramolecular COOH...OOC hydrogen bond. On the other hand, no S-bridged structure was obtained by the corresponding 1:1 reaction with CdI2 and NaI, giving only a mononuclear CoIII species with a [CdI4]2- counteranion, Lambda(L)-[Co(L-Hcys-N,S)(en)2][CdI4] (3). When Lambda(L)-[Co(L-cys-N,S)(en)2]ClO4 having a deprotonated pendent COO- group was reacted with CdCl2 in a 1:1 ratio in water, followed by the addition of NaCl, a one-dimensional (CoIIICdII)n polymeric complex, (Lambda(L))n-[CdCl3{Co(L-cys-N,S)(en)2}]n (4Cl), in which Lambda(L)-[Co(L-cys-N,S)(en)2]+ units are alternately linked by [CdCl3]- moieties through thiolato and carboxylate groups, was constructed. An analogous (CoIIICdII)n polymeric structure having [Cd(NCS-N)3]- moieties, (Lambda(L))n-[Cd(NCS-N)3{Co(L-cys-N,S)(en)2}]n (4NCS), was also produced by the use of Cd(ClO4)2 and NaSCN.     

Probing anion-pi interactions in 1-D Co(II), Ni(II), and Cd(II) coordination polymers containing flexible pyrazine ligands

Two flexible thioether-containing heterocyclic ligands bis(2-pyrazylmethyl)sulfide (L1) and 2-benzylsulfanylmethylpyrazine (L2) have arene rings with differing pi-acidities which were used to probe anion-pi binding in five 1-D coordination polymers formed from the metal salts Co(ClO4)2, Ni(NO3)2, and Cd(NO3)2. In {[Co(L1)(MeCN)2](ClO4)2}infinity (1), {[Ni(L1)(NO3)2]}infinity (2), and {[Cd2(L1)(MeCN)(H2O)(NO3)4].H2O}infinity (3.H2O), the symmetrical ligand L1 was bound facially to the metal center and was bridged through a pyrazine donor to an adjacent metal forming a polymer chain. The folding of L1 formed U-shaped pi-pockets in 1 and 3.H2O which encapsulated free and bound anions, respectively. The anions interacted with the pi-acidic centers in a variety of different binding modes including anion-pi-anion and pi-anion-pi sandwiching. A wider pi-pocket was formed in 2 which also contained anion-pi interactions. The polymer chains in 2 were interdigitated through a rare type of complementary T-shaped N(pyrazine)...pi interaction. In {[Co(L2)(H2O)3](ClO4)2.H2O}infinity (4.H2O) and {[Cd(L2)(H2O)(NO3)2]}infinity (5), the unsymmetrical ligand L2 chelated the metal center and bridged through a pyrazine donor to an adjacent metal forming a polymer chain. The ligand arrangement resulted in the anions in both structures being involved in only anion-pi-anion sandwich interactions. In 4.H2O, the noncoordinated ClO4- anions interacted with only one chain while in 5 the coordinated NO3- anions acted as anion-pi supramolecular synthons between chains. Comparison between the polymers formed with ligands L1 and L2 showed that only the more pi-acidic ring was involved in the anion-pi interactions.     

Hydrothermal and structural chemistry of the zinc(II)- and cadmium(II)-1,2,4-triazolate systems

Hydrothermal reactions of 1,2,4-triazole with zinc and cadmium salts have yielded 10 structurally unique materials of the M(II)/trz/Xn- system, with M(II)=Zn and Cd and Xn-=F-, Cl-, Br-, I-, OH-, NO3-, and SO(4)2- (trz=1,2,4-triazolate). Of the zinc-containing phases, [Zn(trz)2] (1), [Zn2(trz)3(OH)].3H2O (3.3H2O), and [Zn2(trz)(SO4)(OH)] (4) are three-dimensional, while [Zn(trz)Br] (2) is two-dimensional. All six cadmium phases, [Cd3(trz)3F2(H2O)].2.75H2O (5.2.75H2O), [Cd2(trz)2Cl2(H2O)] (6), [Cd3(trz)3Br3] (7), [Cd2(trz)3I] (8), [Cd3(trz)5(NO3)(H2O)].H2O (9.H2O), and [Cd8(trz)4(OH)2(SO4)5(H2O)] (10), are three-dimensional. In all cases, the anionic components Xn- participate in the framework connectivity as bridging ligands. The structural diversity of these materials is reflected in the variety of coordination polyhedra displayed by the metal sites: tetrahedral; trigonal bipyramidal; octahedral. Structures 3, 5, and 7-9 exhibit two distinct polyhedral building blocks. The materials are also characterized by a range of substructural components, including trinuclear and tetranuclear clusters, adamantoid cages, chains, layers, and complex frameworks.     

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.     

Templated synthesis, postsynthetic metal exchange, and properties of a porphyrin-encapsulating metal-organic material

Reaction of biphenyl-3,4',5-tricarboxylate (H(3)BPT) and CdCl(2) in the presence of meso-tetra(N-methyl-4-pyridyl)porphine tetratosylate (TMPyP) afforded porph@MOM-10, a microporous metal-organic material containing CdTMPyP cations encapsulated in an anionic Cd(II) carboxylate framework, [Cd(6)(BPT)(4)Cl(4)(H(2)O)(4)]. Porph@MOM-10 is a versatile platform that undergoes exchange to serve as the parent of a series of porph@MOMs that exhibit permanent porosity and heterogeneous catalytic activity.     

Synthesis and characterization of a novel cadmium-organic framework with trimesic acid and 1,2-bis(4-pyridyl)ethane

The hydrothermal reaction between Cd(NO(3))(2), trimesic acid (H(3)BTC), 1,2-bis(4-pyridyl)ethane (BPE), and triethylamine under mild conditions yielded, after 3 days, a novel three-dimensional metal-organic framework, [Cd(1.5)(BTC)(BPE)(H(2)O)(2)].(H(2)O), which has been characterized structurally using single-crystal and powder X-ray diffraction, elemental analysis, infrared and Raman spectroscopies, thermogravimetry, and differential scanning calorimetry. The structure exhibits a 2-fold interpenetration of identical [Cd(1.5)(BTC)(BPE)(H(2)O)(2)] single frameworks, described as an unusual (9) net. Crystal data: Cd(1.5)C(21)H(21)N(2)O(9), monoclinic, space group C2/c, with a = 10.8264(5) A, b = 17.4563(5) A, c = 24.2605(11) A, beta = 91.978(2) degrees, V = 4582.2(3) A(3), and Z = 8.