title: Structural and thermodiffractometric analysis of coordination polymers. Part II: zinc and cadmium derivatives of the Bim ligand [Bim = bis(1-imidazolyl)methane].
abstract: New polynuclear coordination species containing the ditopic bis(1-imidazolyl)methane (Bim) ligand have been prepared as microcrystalline powders and structurally characterized by ab initio X-ray powder diffraction methods. [Zn(CH3COO)2(Bim)]n contains 1D chains with tetrahedral metal atoms bridged by Bim ligands; [CdBr2(Bim)]n shows a dense packing with hexacoordinated Cd(II) ions and mu-Br and mu-Bim bridges; at variance, the isomorphous [ZnCl2(Bim)]n and [ZnBr2(Bim)]n species contain cyclic dimers based on tetrahedral Zn(II) ions. Thermodiffractometric analysis allowed estimation of the linear thermal expansion coefficients and strain tensors derived there from. Bim-rich phases, with 2:1 ligand-to-metal ratio, were also isolated: ZnBr2(Bim)2(H2O)3 and [Cd(CH3COO)2(Bim)2]n containing cis and trans MN4O2 chromophores, respectively, show 1D polymers built upon M2Bim2 cycles, hinged on the metal ions. In all species the conformation of the Bim ligands is Cs (or nearly so), while in the few sparse reports of similar coordination polymers the alternative C2 one was preferentially observed.
authors.affiliation: Dipartimento di Scienze Chimiche e Ambientali, Università dell'Insubria, via Valleggio 11, 22100 Como, Italy.
authors.forename: Norberto
authors.initials: N
authors.lastname: Masciocchi
authors.forename: Claudio
authors.initials: C
authors.lastname: Pettinari
authors.forename: Enrica
authors.initials: E
authors.lastname: Alberti
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pettinari
authors.forename: Corrado Di
authors.initials: CD
authors.lastname: Nicola
authors.forename: Alessandro Figini
authors.initials: AF
authors.lastname: Albisetti
authors.forename: Angelo
authors.initials: A
authors.lastname: Sironi