Synthesis, crystal structure, spectroscopic and thermal properties of [Et4N][Ta6Br12(H2O)6]Br4·4H2O (Et=ethyl)—A new compound with the paramagnetic [Ta6Br12]3+ cluster core

A new hexanuclear cluster compound, [Et 4N][Ta6Br12(H2O)6]Br4·4H2O (Et =ethyl) (1), with the paramagnetic [Ta6Br12]3+ cluster entity, was synthesized and characterized by elemental and TG/DTA analyses, IR and UV/Vis spectroscopy and by a single-crystal X-ray diffraction study. The presence of the paramagnetic [Ta6Br12]3+ unit was confirmed also by the room-temperature magnetic and EPR measurements. The compound crystallizes in the tetragonal I 41/a space group, with a =14.299(5), c =21.241(5) Å, Z =4, R 1(F )/wR 2(F 2)=0.0296/0.0811. The structure contains discrete [Ta6Br12(H2O)6]3+ cations with an octahedron of metal atoms edge-bridged by bromine atoms and with water molecules occupying all six terminal positions. The cluster units are positioned in the vertices of the three-dimensional (pseudo)diamond lattice. The structure shows similarities with literature reported structures of cluster compounds crystallizing in the diamond View the MathML source(Fd3¯m) space group.