Coordination variety of phenyltetrazolato and dimethylamido ligands in dimeric Ti, Zr, and Ta complexes.

Three structurally diverse 5-phenyltetrazolato (Tz) Ti, Zr, and Ta complexes, namely, (CHN)[Ti(CHN)(CHN)]·1.45CH or (MeNH)[Ti(NMe)(2,3-μ-Tz)(2-η-Tz)]·1.45CH, (1·1.45CH), [Zr(CHN)(CHN)(CHN)]·1.12CH·0.382CHCl or [Zr(MeNH)(NMe)(2,3-μ-Tz)(2-η-Tz)(1,2-η-Tz)]·1.12CH·0.38CHCl (2·1.12CH·0.38CHCl), and (CHN)[Ta(CHN)(CHN)O]·0.25CH or (MeNH)[Ta(NMe)(2,3-μ-Tz)(2-η-Tz)O]·0.25CH (3·0.25CH), where TzH is 5-phenyl-1H-tetrazole, have been synthesized and structurally characterized. All three complexes are dinuclear; the Ti center in 1 is six-coordinate, whereas the Zr and Ta atoms in 2 and 3 are seven-coordinate. The coordination environments of the Ti centers in 1 are similar, and so are the ligations of the Ta centers in 3. In contrast, the two Zr centers in 2 bear a different number of ligands, one of which is a bidentate η-5-phenyltetrazolato ligand that has not been observed previously for d-block elements. The dimethylamido ligand, present in the starting materials, remained unchanged, or was converted to dimethylamine and dimethylammonium during the synthesis. Dimethylamine coordinates as a neutral ligand, whereas dimethylammonium is retained as a hydrogen-bonded entity bridging Tz ligands.