posted on 2018-08-20, 00:00authored byLisa K. Mahnke, Michael Wendt, Christian Näther, Wolfgang Bensch
We
report the rational solvothermal syntheses and crystal structures
of three new antimonato-polyoxovanadates, {Zn(phen)3}2[V14Sb8O42(H2O)]·0.5 phen·17 H2O (1), [{Zn(en)2}2V14Sb8O42]·7 H2O (2), and {Fe(phen)3}2[V14Sb8O42(H2O)]·11
H2O (3), using the water-soluble {Zn(en)3}3[V15Sb6O42(H2O)]·3en·10H2O as
synthon. The solvothermal reactions are fast and product formation
is finished within 24 h. Adjustment of the pH value by application
of an ammonia buffer avoided crystallization of the {V15Sb6O42} core containing products. In
the structure of 1, the en ligands of the starting compound
are in situ exchanged by phen molecules. In 2, one en
ligand of the [Zn(en)3]2+ complexes of
the educt is emitted under the reaction conditions, leading to crystallization
of a layered structure formed by V–O–Zn–O
bonds. Finally, in compound 3, the initially Zn2+-centered complexes are exchanged in situ by Fe2+-centered
complexes with phen ligands. In all three structures, short intercluster
Sb···O separations indicate weak interactions, leading
to aggregates of higher dimensionality. The crystal water molecules
are connected by intermolecular hydrogen bonds, leading to the formation
of different types of water clusters. In addition, the water molecules
are involved in hydrogen bonding to the cluster anions and ligands
of the transition metal complexes.