Mixed-metal Coordination Polymer Research Articles

A new 2-carboxylate-substituted 4,4′-bipyridine ligand: coordination chemistry of 4,4′-bipyridine-2-carboxylic acid and its synthetic intermediate 2-methyl-4,4′-bipyridine

The first monocarboxylate-substituted 4,4'-bipyridine ligand, 4,4'-bipyridine-2-carboxylic acid (4-(pyridin-4-yl)pyridine-2-carboxylic acid (PPCAH)), has been successfully synthesized from 4,4'-bipyridine. Reactions with transition metals zinc and manganese were used to establish the coordination characteristics of the product, 4,4'-bipyridine-2-carboxylic acid, and of the synthetic intermediate, 2-methyl-4,4'-bipyridine, by single-crystal X-ray diffraction. The ligand PPCAH is useful for the formation of metal-containing building blocks that can be used in the assembly of mixed-metal framework materials. The synthesis and structure of one such mixed-metal coordination polymer, Cu(PPCA)(2)HgI(2), is also presented.

Synthesis and characterization of a novel copper(II)–silver(I) mixed-metal coordination polymer Ag[CuL] (L = Schiff base derived from glycylglycine and o-vanillin)

A novel coordination polymer Ag[CuL] (where L = Schiff base derived from glycylglycine and o-vanillin) has been synthesized and characterized by X-ray crystallography. The structure reveals the formation of one-dimensional ribbons.

From Molecular Design to Supramolecular Design: Synthesis and Size-Selective Coordination Chemistry of 1,2-Bis(2‘-pyrazineethynyl) Benzene

The synthesis and coordination chemistry of 1,2-bis(2‘-pyrazineethynyl)benzene are presented. With four Lewis base sites, the ligand may adopt a conformation in which two nitrogen atoms face inward and two nitrogens face out. In this conformation, it may complex transition metal cations either “internally” or “externally”. An “internal” 1:1 complex is formed with silver(I) nitrate, while the larger dicopper(II) tetraacetate moiety does not fit in the internal cavity and is thus externally coordinated by two separate ligands as a 2:2 coordination complex. When mixed with 1 equiv each of silver(I) cation and copper(II) acetate the ligand selectively complexes the cations and a coordination complex with two “internally coordinated” silver(I) cations and an “externally coordinated” dimeric copper(II) acetate moiety is obtained. Self-assembly with 1 equiv of silver(I) nitrate and 2 equiv of copper(II) acetate results in the formation of a mixed-metal coordination polymer with alternating silver and copper cent...

The crystal structure of [Sm(H2O)5][Ru2(bpy)2(CN)7]·11H2O, a novel mixed d–f coordination polymer

This communication describes the crystal structure of the mixed-metal coordination polymer {[Sm(H2O)5][Ru(CN)3(bpy)-(μ-CN)-Ru(CN)3(bpy)]·11H2O}∞, which was isolated in low yield from co-crystallisation of K2[Ru(bpy)(CN)4] with Sm(NO3)3·6H2O. This polymeric chain extends along the a-axis and is constructed from cyanide ligands bridging Ru and Sm metal vertices; it contains both hydrophobic and hydrophilic channels, the latter filled with an H-bonded network of water molecules.

Oligocyanometallic cords as building blocks in luminescent three-dimensional coordination polymers: [Ag 4Cd 2(tren) 2(CN) 6.5][Ag(CN) 1.5] and [Au 2Cd(tren)(CN) 4]·H 2O

The syntheses, structures and luminescent properties of two unusual mixed-metal coordination polymers, namely [Ag 4Cd 2(tren) 2(CN) 7.5][Ag(CN) 1.5] 1 and [Au 2Cd(tren)(CN) 4]·H 2O 2 (tren = tris(2-aminoethyl)amine), are presented. Both compounds contain abnormal metal cords of oligocyanometallic anions as building blocks wherein the d 10–d 10 interaction plays a crucial role in the metal–metal assembly.

Novel ferrocene-based mixed-metal coordination polymers

A novel 2D ferrocene-containing sandwich sheet coordination polymer, consisting of NaZnO inorganic inner and ferrocene-packing outer layers, has been achieved by simply diffusing a solution of Zn(BF4)2 into a solution of 1,1′-ferrocenedicarboxylic acid in the presence of NaOH.

A novel 2-D interlinking zigzag-chain d-f mixed-metal coordination polymer generated from an organometallic ligand.

A flexible organometallic ligand, 1,1'-ferrocenedicarboxylic acid, was incorporated in the self-assembly of a d-f mixed-metal coordination polymer featuring a 2-D interlinking zigzag-chain network and bearing two kinds of bridging conformations.

Novel M(II)–Hg(II) coordination polymers generated from metal-containing building blocks M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu, Ni, Co) and HgCl2

Abstract A new class of M(II)–Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)2HgCl2 (4), [Co(2-pyrazinecarboxylate)2(HgCl2)2] · 0.61H2O (5) and [Ni(2-pyrazinecarboxylate)2(HgCl2)2] · 0.77H2O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu(II), Co(II), Ni(II)), with HgCl2. Compounds 4–6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a=17.916(5) A, b=7.223(2) A, c=13.335(4) A, β=128.726(3)°, V=1346.2(6) A3, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)–Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P 1 , with a=6.3879(7) A, b=6.6626(8) A, c=13.2286(15) A, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) A3, Z=1. Compound 6 also crystallized in the triclinic space group P 1 , with a=6.3543(8) A, b=6.6194(8) A, c=13.2801(16) A, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) A3, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)⋯M(II)⋯Hg(II) units are connected by Hg2Cl2 linkages to produce a novel M(II)–Hg(II) (MCo(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M–M′–M′–M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)2 · (H2O)2 (MCu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl2 depending on the metal cation contained within them.

Synthesis and characterization of a novel copper(II)silver(I) mixed-metal coordination polymer: Ag[Cu(2-pyrazinecarboxylate)2](H2O)(NO3)

The first example of a Cu(II)Ag(I) mixed-metal coordination polymer, Ag[Cu(2-pyrazinecarboxylate)2](H2O)(NO3 )( 3), has been prepared via hydrothermal reaction of Cu(II)(2-pyrazinecarboxylate)2 (1) or Cu(II)(2-pyrazinecarboxylate)2(H2O)2

Metal-containing ligands for mixed-metal polymers: novel Cu(II)-Ag(I) mixed-metal coordination polymers generated from [Cu(2-methylpyrazine-5-carboxylate)2(H2O)].3H2O and silver(I) salts.

One Cu(II)-containing ligand and two Cu(II)-Ag(I) mixed-metal coordination polymers have been synthesized. [Cu(2-methylpyrazine-5-carboxylate)2(H2O)].3H2O (1) was obtained as a molecular complex with two uncoordinated nitrogen donors by the reaction of 2-methylpyrazine-5-carboxylate sodium with CuCl(2).2H2O in water. Compound 1 crystallized in the triclinic space group P1, with a = 10.498(2) A, b = 11.000(2) A, c = 8.1424(16) A, alpha = 98.33(3) degrees, beta = 101.83(3) degrees, gamma = 66.68(3) degrees, and Z = 2. Reactions of 1 with silver(I) salts have been studied. Two Cu(II)-Ag(I) mixed-metal coordination polymers, namely, Ag[Cu(2-methylpyrazine-5-carboxylate)2.(H2O)2](BF4) (2) and Ag[Cu(2-methylpyrazine-5-carboxylate)2.(H2O)2](NO3) (3), have been generated by treating 1 with AgBF4 and AgNO3, respectively. Compound 2 crystallized in the monoclinic space group C2/c, with a = 25.827(5) A, b = 9.6430(19) A, c = 7.4525(15) A, beta = 94.74(3) degrees, and Z = 4. Compound 3 also crystallized in the monoclinic space group C2/c, with a = 25.855(5) A, b = 9.782(2) A, c = 7.1201(14) A, beta = 96.90(3) degrees, and Z = 4. The main structural feature in both 2 and 3 is a zigzag Cu(II)-Ag(I) mixed-metal chain, in which the alternating Cu(II) and Ag(I) centers are linked by 2-methylpyrazine-5-carboxylate spacers. The effect of the nitrate counterion was illustrated by compound 3, in which a novel [Ag+...NO3-] coordination chain has been found which acts as the connector to cross-link the one-dimensional zigzag chains into a three-dimensional network. In addition, an identical interchain O-H...O hydrogen bonding system has been found in both 2 and 3 and has been shown to play a significant role in directing the alignment of the one-dimensional mixed-metal polymer chains in the crystalline state. The magnetic susceptibilities of 2 and 3 were measured and found to follow the Curie law (mu eff = 1.85 for 2 and 1.83 for 3).

Simultaneous polymerization and crystallization: a new method for the preparation of mixed-metal coordination polymers

Abstract : The usefulness of simultaneous polymerization and crystallization as a preparative tool for transition metal polymers is established; syntheses of both stable and metastable mixed-metal (M=Ni,Co) polymers are described. The metastable polymers show solid-state reactivity as well as room-temperature photochromism. (Author)