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We synthesized and studied the polymeric compound {[Cu2(µ4-EDTA)(Him)2] 2H2O}n (1). The single-crystal structure is reported along with an in depth characterization of its thermal stability (TGA), spectral properties (FT-IR, Vis-UV and RSE), and magnetic behavior. The crystal consists of infinite 2D-networks built by centrosymmetric dinuclear motifs, constructed by means of a bridging anti,syn-carboxylate group from each asymmetric unit. Each layer guides Him ligands toward their external faces. They are connected by intermolecular (Him)N-H···O(carboxylate) bonds and antiparallel π–π stacking between symmetry related pairs of Him ligands, and then pillared in a 3D-network with parallel channels, where disordered water molecules are guested. About half of the labile water is lost from these channels over a wide temperature range (r.t. to 210 °C) before the other one, most strongly retained by the cooperating action of (water)O1-H(1A)···O(carboxylate) and (water) O1-H(1B)···π(Him) interactions. The latter is lost when organic ligands start to burn. ESR spectra and magnetic measurements indicated that symmetry related Cu(II) centers connected by the bridging carboxylate groups behave magnetically not equivalently, enabling an exchange interaction larger than their individual Zeeman energies. [ABSTRACT FROM AUTHOR]

Mixed ligand MII-complexes (M Co Zn) with pyridine-2,6-dicarboxylate(2-) chelator (pdc) and adenine (Hade) have been synthesized and studied by X-ray diffraction and other spectral and thermal methods: [Cu(pdc)(H(N9)ade)(H2O)] (1), [Cu2(pdc)2(H2O)2(μ2-N3,N7-H(N9)ade)]·3H2O (2), trans-[M(pdc)(H(N9)ade)(H2O)2]·nH2O for M Co (3-L, 3-M, 3-H) or Zn (4-L, 4-H), where n is 0, 1 or 3 for the ‘lowest’ (L), ‘medium’ (M) and ‘highest’ (H) hydrated forms, and the salt trans-[Ni(pdc)(H2(N1,N9)ade)(H2O)2]Cl·2H2O (5). In all the nine compounds, both neutral and cationic adenine exist as their most stable tautomer and the molecular recognition pattern between the metal-pdc chelates and the adenine or adeninium(1+) ligands involves the M N7 bond in cooperation with an intra-molecular N6 H⋯O(coordinated carboxylate) interligand interaction. In addition the dinuclear copper(II) compound (2) has the Cu N3 bond and the N9 H⋯O(coord. carboxylate) interaction. The structures of mononuclear ternary complexes proved that the molecular recognition pattern is the same irrespective of (a) the coordination geometry of the complex molecule, (b) the different hydrated forms of crystals with Co or Zn, and (c) the neutral of cationic form of the adenine ligand. These features are related to the mer-NO2 chelating ligand conformation (imposed by the planar rigidity of pdc) as a driving force for the observed metal binding mode. [ABSTRACT FROM AUTHOR]

In the title complex, [Cu(C4H6N2O3)(C5H5N5)(H2O)], the CuII atom is five-coordinated in a square-pyramidal geometry by a tridentate glycylglycinate ligand (glygly), an N atom from an adenine ligand (Hade) and a water molecule in the apical position. The Hade coordination is reinforced by an intramolecular hydrogen-bonding interaction. A much lower precision structure has already been determined using intensities collected by the film method [Tomita, Izumo & Fujiwara (1973). Biochem. Biophys. Res. Commun. 54, 96–99]. [ABSTRACT FROM AUTHOR]

In the title compound, [Cu(C11H10ClNO4)(C3H4N)2], the CuII atom is in a square-pyramidal coordination geometry, with the two imidazole ligands in cis positions and the N-(4-chlorobenzyl)iminodiacetate ligand occupying the apical and two cis-basal positions. In the crystal structure, molecules are linked into sheets by N—H...O hydrogen bonds. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of copper(II) hydroxocarbonate, mandelic acid (H2MANO) and 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) in water affords [Cu(bpy)(μ2-MANO)]2 ·8H2O (1), [Cu(bpy)(MANO)]·4H2O (2) and the opened tetranuclear hydroxo-bridged copper(II) complexes of formulae [Cu4(μ3-OH)2(μ2-MANO)2(bpy)4](phglyo)2 ·8H2O (3) (phglyo=phenylglyoxylate) or [Cu4(μ3-OH)2(μ2-OH)2(OH2)2(phen)4](Bza)2(OH)2 ·5H2O (4) (Bza=benzoate), respectively. The compounds have been characterized by spectroscopic techniques and studied by single-crystal X-ray diffractometry. The formation of 3 and 4 takes place in basic media through dehydrogenation or oxidative dehydrogenation followed by in situ oxidative decarboxylation of mandelic acid to phenylglyoxylate or benzoate, respectively. These results indicate that cooperative catalysis of diimine ancillary ligands and copper(II) is essential. [Copyright &y& Elsevier]

Abstract: By reaction of Cu2CO3(OH)2 and H4EGTA with or without imidazole, the compounds [Cu2(EGTA)(H2O)2]·2H2O (1), [Cu2(EGTA)(Him)2] n (2) and [Cu2(EGTA)(Him)4]·4H2O (3) have been prepared. The EGTA acts in a μ2-bridging mode, with each half being tripodal-tetradentate in mer-NO2 +O(ether, apical) or NO+O(carboxy, apical)+O(ether, apical) conformation for compounds 1 and 2 or 3 and [Cu2(EGTA)(en)2]·4H2O (4), respectively, as expected from the number of N donor atoms (0 and 1 or 2) supplied by the auxiliary ligands. The Cu–O(ether) bond length increases in the series 1 < 2 < 3 < 4, mainly influenced by the coordination number (5 or 6) of the copper(II) atom, the influence of the Jahn–Teller effect on it, giving from 4+1 to 4+1+1 surroundings, and the number of N atoms (1 to 3) among the four closest donor of the Cu(II) atom. [Copyright &y& Elsevier]