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, (C 2 H 8 N)[Ti 2 (C 7 H 5 N 4 ) 5 (C 2 H 6 N) 4 ]·1.45C 6 H 6 or (Me 2 NH 2 )[Ti 2 (NMe 2 ) 4 (2,3-μ-Tz) 3 (2-η 1 -Tz) 2 ]·1.45C 6 H 6 , (1·1.45C 6 H 6 ), [Zr 2 (C 7 H 5 N 4 ) 6 (C 2 H 6 N) 2 (C 2 H 7 N) 2 ]·1.12C 6 H 6 ·0.382CH 2 Cl 2 or [Zr 2 (Me 2 NH) 2 (NMe 2 ) 2 (2,3-μ-Tz) 3 (2-η 1 -Tz) 2 (1,2-η 2 -Tz)]·1.12C 6 H 6 ·0.38CH 2 Cl 2 (2·1.12C 6 H 6 ·0.38CH 2 Cl 2 ), and (C 2 H 8 N) 2 [Ta 2 (C 7 H 5 N 4 ) 8 (C 2 H 6 N) 2 O]·0.25C 7 H 8 or (Me 2 NH 2 ) 2 [Ta 2 (NMe 2 ) 2 (2,3-μ-Tz) 2 (2-η 1 -Tz) 6 O]·0.25C 7 H 8 (3·0.25C 7 H 8 ), 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 2 -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.