Aqua­(4,4′-dimethyl-2,2′-bipyridine-κ2 N,N′)(nitrato-κO)(nitrato-κ2 O,O′)zinc

In the title compound, [Zn(NO3)2(C12H12N2)(H2O)], the ZnII atom is six-coordinated in a distorted octa­hedral geometry by two N atoms from a chelating 4,4′-dimethyl-2,2′-bipyridine ligand, one water O atom, one O atom from a monodentate nitrate anion and two O atoms from a chelating nitrate anion. In the crystal, there are aromatic π–π contacts between the pyridine rings [centroid–centroid distances = 3.9577 (13) Å] and inter­molecular O—H⋯O and C—H⋯O hydrogen bonds

2,2 ‘-Bipyridine,1,10-phenanthroline and 2,2 ‘: 6,2 ‘’-terpyridine in gallium(III) chemistry: Complexes containing the Ga-2(III)(mu-OH)(2)(4+) core

The reactions of Ga(NO3)(3) center dot 9H(2)O with 2,2’-bipyridine (bpy), 1, 10-phenanthroline (phen) and 2,2’:6’,2”-terpyridine (terpy) in alcohols afford the complexes [Ga-2(OH)(2)(bpy)(4)](NO3)(4) (1), [Ga-2(OH)(2)(phen)(4)](NO3)(4) (2) and [Ga-2(OH)(2)(H2O)(2)(terpy)(2)](NO3)(4) (3), respectively, in good yields. The crystal structures of 1 center dot 1.3MeOH center dot 1.4H(2)O, 2 center dot 4.5MeOH and 3 have been solved by single-crystal X-ray crystallography. The three complexes contain the Ga-2(III)(mu-OH)(2)(4), core. Four nitrogen atoms from two chelating bpy (1) or phen (2) complete distorted octahedral coordination at each metal centre. In 3 one tridentate chelating terpy and one aquo ligand complete six coordination at each Ga-III atom. The crystal structure of 2 - 4.5MeOH is stabilized by hydrogen bonds and intermolecular pi-pi stacking interactions, while in 3 hydrogen bonds create a double-chain, ladder-like architecture. Characteristic IR data are discussed in terms of the nature of bonding and the structures of the three complexes. The H-1 NMR spectra of complexes 2 and 3 suggest the presence of the free ligand and one solution species containing the coordinated ligand. The structure of the cation [Ca-2(OH)(2)(bpy)(4)](4+) is retained in D2O as deduced by the 2D homonuclear COSY map. (c) 2006 Elsevier B.V. All rights reserved