Variable Chains Found in Mixed Transition Metal Oxyfluorides with Heterocyclic Ligands

다국어 초록 (Multilingual Abstract)

<P>Various chain structures of six novel metal oxyfluorides containing d<SUP>0</SUP> and d<SUP>10</SUP> transition metal asymmetric polyhedra, i.e., [Zn(mpz)<SUB>4</SUB>][TiF<SUB>6</SUB>] (<B>1</B>), [Cd(mpz)<SUB>4</SUB>][TiF<SUB>6</SUB>] (<B>2</B>), [Zn(mpz)<SUB>3</SUB>][ZrF<SUB>6</SUB>] (<B>3</B>), [Cd(pz)<SUB>4</SUB>]<SUB>3</SUB>[ZrF<SUB>6</SUB>][ZrF<SUB>8</SUB>] (<B>4</B>), [Zn(pz)<SUB>4</SUB>]<SUB>2</SUB>[NbOF<SUB>5</SUB>]<SUB>2</SUB> (<B>5</B>), and [Cd(pz)<SUB>4</SUB>][NbOF<SUB>5</SUB>] (<B>6</B>; mpz = 3-methylpyrazole; pz = pyrazole), were synthesized by hydrothermal methods. Compounds <B>1</B>, <B>2</B>, <B>5</B>, and <B>6</B> consist of linear chains, whereas compounds <B>3</B> and <B>4</B> are composed of zigzag chains. Careful structural analysis suggests that the hydrogen bonding network and distinctive <I>cis</I>/<I>trans</I>-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 M<SUP>2+</SUP> 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.</P><P>The diverse chain structures in mixed transition metal oxyfluorides are attributable to the distinctive structure-directing anionic groups and hydrogen bonding interactions.</P>
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