Preparation and characterization of oxorhenium(V) complexes with 2,2′-biimidazole:: The strong affinity of coordinated biimidazole for chloride ions via N-H•••Cl- hydrogen bonding

N,N'-Dimethylbiimidazole and bipyridine (N-N) react with ReOCl3(OPPh3)(Me2S) to give mer-ReOCl3(N-N) compounds. Nonmethylated biimidazole forms a trans-O,O [ReOCl2(OPPh3)(biimH(2))](+) cation, which is tightly associated with the Cl- counterion via N-H . . . Cl- hydrogen bonding. Hydrolysis of ReOCl3(biimMe(2)) in wet acetone (5% water) leads to the linear ore-bridged dinuclear species [{OReCl2(biimMe(2))}(2)(mu -O)] containing chelated biimMe(2). Acetone solutions containing only 1% water yield the bent ore-bridged dinuclear species [{OReCl2}(2)(mu -O)(mu -biimMe(2))(2)], where each Re center retains the ReO2Cl2N2 coordination but the biimMe(2) ligands are bridging. The linear ore-bridged [{OReCl2(biimH(2))}(2)(mu -O)] complex obtained with nonmethylated biimidazole includes two Cl- ions held via N-H . . . Cl- hydrogen bonds, leading to a dianionic [{OReCl2(biimH(2). . . Cl)}(2)(mu -O)](2-) unit in the crystals of the PPh4+ salt. The compounds are characterized by IR and NMR spectroscopies, and the structures of [ReOCl2(OPPh3)(biimH(2))]Cl, [{OReCl2(biimH(2))}(2)(mu -O)](PP4Cl)(2). 2H(2)O, and [{OReCl2}(2)(mu -O)(mu -biimMe(2))(2)].acetone are determined by X-ray diffraction.