The Preparation, Characterization, X-ray Structural Analysis, and Thermogravimetric Analysis of Tetrakis[1,3-Dimethyl-2(3H)-Imidazolethione]Zinc(II) Nitrate and Tetrafluoroborate

Abstract

Two new compounds, [Zn(dmit)4][BF4]2 and [Zn(dmit)4][NO3]2, have been synthesized and characterized via standard solid and solution state methods including single crystal X-ray crystallography (dmit = 1,3-dimethyl-2(3H)-imidazolethione). [Zn(dmit)4][BF4]2 crystallizes in space group Pbcn with a = 11.954(2) A, b = 21.260(4) A, c = 12.749(3) A, Z = 4. [Zn(dmit)4][NO3]2 crystallizes in space group I 4 1 /a with a = b = 11.091(4) A, c = 22.713(5) A, Z = 4. Both structures display a compressed tetrahedral geometry in the zinc coordination sphere similar to previously reported isopropyl and n-butyl analogs. The degree of distortion is closer to that noted for the recently reported methyl isopropyl analog than to the methyl n-butyl complex. There are no significant differences between the nitrate and tetrafluoroborate coordination spheres, and the source of distortion appears to be close intramolecular contacts. Thermogravimetric analysis results suggest that both complexes decompose to yield ZnS2 instead of ZnS. A two new ionic complexes of 1,3-dmethyl-2(3H)-imidazolethione (dmit) containing tetra-S-coordinated Zn(II) have been synthesized and structurally characterized. Both nitrate and tetrafluoroborate analogs have distorted tetrahedral coordination geometry around the zinc ions similar to that noted for complexes with bulkier alkyl imidazolethiones. There are no significant differences between the nitrate and tetrafluoroborate coordination spheres, and the source of distortion appears to be close intramolecular contacts.