Solvothermal syntheses and structural characterization of a series of metal–hydroxycarboxylate coordination polymers

Synthesis, characterization, and crystal structure of aqua-bis-(4,4'-dimeth-oxy-2,2'-bi-pyridine)[μ-(2R,3R)-tartrato(4-)]dicopper(II) octa-hydrate

Typical electroless copper baths (ECBs), which are used to chemically deposit copper on printed circuit boards, consist of an aqueous alkali hydroxide solution, a copper(II) salt, formaldehyde as reducing agent, an l-(+)-tartrate as complexing agent, and a 2,2'-bi-pyridine derivative as stabilizer. Actual speciation and reactivity are, however, largely unknown. Herein, we report on the synthesis and crystal structure of aqua-1κO-bis-(4,4'-dimeth-oxy-2,2'-bi-pyri-dine)-1κ2 N,N';2κ2 N,N'-[μ-(2R,3R)-2,3-dioxidosuccinato-1κ2 O 1,O 2:2κ2 O 3,O 4]dicopper(II) octa-hydrate, [Cu2(C12H12N2O2)2(C4H2O6)(H2O)]·8H2O, from an ECB mock-up. The title compound crystallizes in the Sohncke group P21 with one chiral dinuclear complex and eight mol-ecules of hydrate water in the asymmetric unit. The expected retention of the tartrato ligand's absolute configuration was confirmed via determination of the absolute structure. The complex mol-ecules exhibit an ansa-like structure with two planar, nearly parallel bi-pyridine ligands, each bound to a copper atom that is connected to the other by a bridging tartrato 'handle'. The complex and water mol-ecules give rise to a layered supra-molecular structure dominated by alternating π stacks and hydrogen bonds. The understanding of structures ex situ is a first step on the way to prolonged stability and improved coating behavior of ECBs.

Non-centrosymmetric coordination polymer with a highly hindered octahedral copper center bridged by mandelate

A novel chiral coordination polymer, [Cu(C(6)H(5)CH(OH)COO)(μ-C(6)H(5)CH(OH)COO)] (1-L and 1-D), was synthesized through a reaction of copper acetate with L-mandelic acid at room temperature. Although previously reported copper mandelate prepared by hydrothermal reaction was a centrosymmetric coordination polymer because of the racemization of mandelic acid, the current coordination polymer shows noncentrosymmetry and a completely different structure from that previously reported. The X-ray crystallography for 1-L revealed that the copper center of the compound showed a highly distorted octahedral structure bridged by a chiral mandelate ligand in the unusual coordination mode to construct a one-dimensional (1D) zigzag chain structure. These 1D chains interdigitated each other to give a layered structure as a result of the formation of multiple aromatic interactions and hydrogen bonds between hydroxyl and carboxylate moieties at mandelate ligands. The coordination polymer 1-L belongs to the noncentrosymmetric space group of C2 to show piezoelectric properties and second harmonic generation (SHG) activity.

Poly[[(1,10-phenanthroline)(μ-l-tartrato)zinc] hexa-hydrate]

The title compouand {[Zn(C₄H₄O₆)(C₁₂H₈N₂)]·6H₂O}_n, has a linear chain structure parallel to [100] with Zn(C₄H₄O₆)(C₁₂H₈N₂) repeat units; the asymmetric unit consists of one Zn²⁺ cation, one l-tartrate dianion, one 1,10-phenanthroline and six free water mol­ecules. The Zn atom is in a distorted octa­hedral ZnN₂O₄ coordination environment. The crystal structure is stabilized by O—H⋯O hydrogen bonds and π–π stacking of the phenanthroline units [centroid–centroid distances in the range 3.552 (2)–3.625 (2)Å] occurs between the chains. The title compound is isotypic with the Cu and Mn analogues.

catena-Poly[[[(2-phenylacetato-κO)zinc(II)]bis[μ-4,4′-(disulfanediyl)dipyridine-κ2N:N′]] monohydrate]

In the title compound, {[Zn(C₈H₇O₂)₂(C₁₀H₈N₂S₂)₂]·H₂O}_n, the Zn^II atom is coordinated by four N atoms from four 4,4′-(disulfanedi­yl)dipyridine (bpds) ligands and two O atoms from two 2-phenyl­acetate anions in a distorted octa­hedral coordination geometry. The two bpds ligands of the same axial chirality bridge Zn^II atoms, generating repeated rhomboidal chains, which are linked by O—H⋯O hydrogen bonds into a ladder structure.

Poly[[diaqua-(μ(4)-l-tartrato)(μ(2)-l-tartrato)dizinc(II)] tetra-hydrate]

In the title compound, {[Zn(C₄H₄O₆)(H₂O)]·2H₂O}_n, the l-tartrate ligands adopt μ₄- and μ₂-coordination modes. The Zn^II atom adopts an octa­hedral geometry and is chelated by two kinds of l-tartrate ligands through the hydr­oxy and carboxyl­ate groups and coordinated by one unchelating carboxyl­ate O atom and one water mol­ecule. In the crystal, the l-tartrate ligands link the Zn^II atoms, forming a two-dimensional coordination layer; these layers are futher linked into a three-dimensional supra­molecular network by O—H⋯O hydrogen bonds between the two-dimensional coordin­ation layers and the uncoordinated water mol­ecules. The latter are equally disordered over two positions.

catena-Poly[[diaqua-(1H-imidazo[4,5-f][1,10]phenanthroline)cobalt(II)]-μ-sulfato]

The Co(II) ion in the title complex, [Co(SO(4))(C(13)H(8)N(4))(H(2)O)(2)](n), has a slightly distorted octa-hedral coordination environment formed by two O atoms from two symmetry-related bridging sulfate ligands, two N atoms from a bis-chelating 1H-imidazo[4,5-f][1,10]phenanthroline (IPL) ligand and two O atoms from coordinated water mol-ecules. The bridging sulfate ligands connect Co(II) ions to form a one-dimensional chain along the b-axis direction. In the crystal structure, inter-molecular O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds link the chains into a three-dimensional network.

catena-Poly[[[di-μ(2)-hydroxido-bis-[(di-2-pyridylamine)nickel(II)]]-μ-fumarato] dihydrate]

The Ni^II ion in the one-dimensional title complex, {[Ni₂(C₄H₂O₄)(OH)₂(C₁₀H₉N₃)₂]·2H₂O}_n, has a distorted square-pyramidal coordination environment formed by three O atoms from two bridging hydroxide groups and one carboxyl­ate group of the fumarate ligand and two pyridine N atoms from a di-2-pyridylamine (dpa) ligand. Two hydroxide groups link adjacent metal centers, forming a centrosymmetric four-membered [Ni₂(OH)₂] ring. In the crystal structure, the H atoms of the bridging hydroxide groups form inter­molecular hydrogen bonds to both water mol­ecules. These are further linked to the uncoordinated O atoms of the carboxyl­ate groups and the NH group of a dpa ligand to generate a three-dimensional network from the chains of the coordination polymer.

Bis[bis(1-oxo-2-pyridyl)aminato]copper(II) tetrahydrate

In the title compound, [Cu(C₁₀H₈N₃O₂)₂]·4H₂O, the Cu^II ion has a distorted octa­hedral coordination formed by four O [Cu—O = 2.051 (3)–2.083 (4) Å] and two N [Cu—N = 1.985 (4) and 1.996 (4) Å] atoms from two tridentate bis­(1-oxo-2-pyrid­yl)aminate ligands. In the two ligands, the pyridyl rings form dihedral angles of 21.0 (1) and 15.5 (1)°. The crystal packing exhibits an extensive network of O—H⋯O hydrogen bonds and π–π inter­actions proved by short distances of 3.650 (1) and 3.732 (2) Å between the centroids of pyridyl rings of neighbouring mol­ecules.

Bis(μ-N,N'-di-4-pyridylpyridine-2,6-diamine)bis[dimethacrylatocobalt(II)] dihydrate

The Co^II ion in the title complex, [Co₂(C₄H₅O₂)₄(C₁₅H₁₃N₅)₂]·2H₂O, has a distorted square-planar coordination formed by the bridging bidentate N,N′-di-4-pyridylpyrid­ine-2,6-diamine (dapmp) ligands and two monodentate carboxyl­ate groups from methacrylates. Two dapmp ligands bridge two Co atoms, forming a dinuclear complex arranged around an inversion centre. N—H⋯O and O—H⋯O hydrogen bonds involving the solvent water mol­ecule result in the formation of a three-dimensional network. The aliphatic moiety of one of the methacrylate groups is disordered over two positions with fixed occupancies of 0.67 and 0.33.