Unprecedented Architecture of the Linear (mu-Cl)-Tetranuclear Cobalt Complex with Quaterpyridine Ligand

作者：Ciesielski Artur; Patroniak Violetta; Kubicki Maciej^*

来源：Journal of Chemical Crystallography, 2011, 41(12): 1884-1888.

DOI：10.1007/s10870-011-0195-3

• Co complexes
• Eu complexes
• Centro-noncentro ambiguity
• Crystal packing

The cationic tetranuclear cobalt complex of the geometry Cl-CoL-Cl-CoL-Cl-CoL-Cl-CoL (where L is 6,6'''-dimethyl-2,2':6',2'':6'',2'''-quaterpyridine) has been synthesized and structurally characterized. The structural unit contains one cationic ligand, two Eu(NO(3))(5) dianions, two solvent acetonitrile molecules and some disordered water molecules. The salt crystallizes in the monoclinic space group C2/c with a = 17.405 (3) , b = 28.700 (5) and c = 23.350 (5) , beta = 95.14 (2)A(0). The cation is C (2) -symmetrical, the central Cl atom lies on the twofold axis. This structure is another example of centro-noncentro ambiguity: in the centrosymmetric model, the terminal Cl in the cation is disordered between the two ends of the chain. The Eu ion is coordinated by five nitro groups, the coordination number is 10-two oxygen atoms of every nitro group are involved in the coordination with the mean Eu-O distance of 2.52(3) . The quaterpyridine ligands are folded, the dihedral angle between the terminal ring planes is 29.3 (2) and 32.8 (3)A(0) in the two symmetry independent ligands. In the crystal structure the coulombic attraction between the cations and anions seems to be a driving force; the ionic species make a chessboard-like pattern, the voids in such created structure are filled with the solvent-acetonitrile molecules as well as by some disordered waters.

• 出版日期2011-12