title: Crystal structures of bis- and hexakis[(6,6'-di-hydroxy-bipyridine)copper(II)] nitrate coordination complexes.
abstract: Two multinuclear complexes synthesized from Cu(NO3)2 and 6,6'-di-hydroxy-bipyridine (dhbp) exhibit bridging nitrate and hydroxide ligands. The dinuclear complex (6,6'-di-hydroxy-bipyridine-2κ(2) N,N')[μ-6-(6-hy-droxy-pyridin-2-yl)pyridin-2-olato-1:2κ(3) N,N':O (2)](μ-hydroxido-1:2κ(2) O:O')(μ-nitrato-1:2κ(2) O:O')(nitrato-1κO)dicopper(II), [Cu2(C10H7N2O2)(OH)(NO3)2(C10H8N2O2)] or [Cu(6-OH-6'-O-bpy)(NO3)(μ-OH)(μ-NO3)Cu(6,6'-dhbp)], (I), with a 2:1 ratio of nitrate to hydroxide anions and one partially deprotonated dhbp ligand, forms from a water-ethanol mixture at neutral pH. The hexa-nuclear complex bis-(μ3-bi-pyridine-2,2'-diolato-κ(3) O:N,N':O')tetra-kis-(6,6'-di-hydroxy-bipyridine-κ(2) N,N')tetra-kis-(μ-hydroxido-κ(2) O:O')bis-(methanol-κO)tetra-kis-(μ-nitrato-κ(2) O:O')hexa-copper(II), [Cu6(C10H6N2O2)2(CH4O)2(OH)4(NO3)4(C10H8N2O2)4] or [Cu(6,6'-dhbp)(μ-NO3)2(μ-OH)Cu(6,6'-O-bpy)(μ-OH)Cu(6,6'dhbp)(CH3OH)]2, (II), with a 1:1 NO3-OH ratio and two fully protonated and fully deprotonated dhbp ligands, was obtained by methanol recrystallization of material obtained at pH 3. Complex (II) lies across an inversion center. Complexes (I) and (II) both display intra-molecular O-H⋯O hydrogen bonding. Inter-molecular O-H⋯O hydrogen bonding links symmetry-related mol-ecules forming chains along [100] for complex (I) with π-stacking along [010] and [001]. Complex (II) forms inter-molecular O-H⋯O hydrogen-bonded chains along [010] with π-stacking along [100] and [001].
authors: Department of Chemistry, University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487-0336, USA.
authors: Deidra L
authors: DL
authors: Gerlach
authors: Department of Chemistry, Drexel University, 3141 Chestnut St., Philadelphia, PA 19104, USA.
authors: Ismael
authors: I
authors: Nieto
authors: Department of Chemistry, Drexel University, 3141 Chestnut St., Philadelphia, PA 19104, USA.
authors: Corey J
authors: CJ
authors: Herbst-Gervasoni
authors: Department of Chemistry, Illinois State University, Campus Box 4160, Normal, IL 61790-4160, USA.
authors: Gregory M
authors: GM
authors: Ferrence
authors: Department of Chemistry, Youngstown State University, One University Plaza, Youngstown, OH 44555, USA.
authors: Matthias
authors: M
authors: Zeller
authors: Department of Chemistry, University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487-0336, USA.
authors: Elizabeth T
authors: ET
authors: Papish
keywords: copper; crystal structure; di­hydroxy­pyridine; potential water oxidation catalysts