Variable Chains Found in Mixed Transition Metal Oxyfluorides with Heterocyclic Ligands

Various chain structures of six novel metal oxyfluorides containing d(0) and d(10) transition metal asymmetric polyhedra, i.e., [Zn(mpz)(4)][TiF6] (1), [Cd(mpz)(4)][TiF6] (2), [Zn(mpz)(3)][ZrF6] (3), [Cd(pz)(4)](3)[ZrF6][ZrF8] (4), [Zn-(pz)(4)](2)[NbOF5](2) (5), and [Cd(pz)(4)][NbOF5] (6; mpz = 3-methylpyrazole; pz = pyrazole), were synthesized by hydrothermal methods. Compounds 1, 2, 5, and 6 consist of linear chains, whereas compounds 3 and 4 are composed of zigzag chains. Careful structural analysis suggests that the hydrogen bonding network and distinctive cis/trans-directing anionic polyhedra are responsible for the diverse chain structures. The title compounds reveal optical band gaps in the range of 5.04-5.22 eV, which might be from the octahedral distortion of M2+ cations and the corresponding electronic transitions. Thorough spectroscopic and thermogravimetric analyses, as well as the magnitude of dipole moments and out-of-center distortions, were used to characterize the reported compounds.