Substitution reactions of tetrahydrofuran in [Cr(thf)3Cl3] with mono and bidentate N-donor ligands: X-ray crystal structures of [Cr(bipy)(OH2)Cl3] and [HpyNH2][Cr(bipy)Cl4]

Substitution of thf ligands in [Cr(thf)3Cl3] and [Cr(thf)2(OH2)Cl3] was investigated. 2,2′-Bipyridine (bipy) was reacted with [Cr(thf)3Cl3] to form [Cr(bipy)(thf)Cl3] (1), which was subsequently reacted with water to give [Cr(bipy)(OH2)Cl3] (2). Reaction of 1 with acetonitrile (CH3CN), pyridine (py) and pyridine derivatives to form [Cr(bipy)(L)Cl3] (L = CH3CN 3, py 4 and 4-pyR with R = NH2 5, But 6 and Ph 7). In addition, the substitution of bipy in [Cr(thf)3Cl3] was followed by 1H NMR spectroscopy at room temperature, which showed completion of the reaction in ca. 100 min. Complex 2 was characterised by single crystal X-ray diffraction. The theoretical powder diffraction pattern of 2 was compared to the experimentally obtained powder X-ray diffraction pattern, and shows excellent agreement. The dimer [Cr2(bipy)2Cl4(μ-Cl)2] was cleaved asymmetrically to give the anionic complex [Cr(bipy)Cl4]− (8) and [Cr(bipy)2Cl2]+ (9). Complexes 8 and 9 were characterised by single crystal X-ray diffraction.