A Novel Synthetic Route to Tantalum–Zinc Neophylidyne Complexes Stabilized by ortho ‐Chelating Arylamine Ligands; the X‐Ray structure of [TaCl 2 (μ‐C 6 H 4 CH 2 NMe 2 −2)(μ‐CCMe 2 Ph)ZnCl(THF)]

A dimeric tantalum‐zinc neophylidyne complex proposed to be [{{TaCl 2 (μ‐CCMe 2 Ph)(μ‐Cl)(THF) 2 }{Zn(μ‐Cl)}} 2 ]( 5a ), which can be prepared easily on a scale of 50 mmol, is an ideal starting material for the synthesis of mono‐ and bis( ortho )‐chelated arylamine alkylidyne species such as the red Ta‐Zn neophylidyne complexes [TaCl 2 (μ‐C 6 H 4 CH 2 NMe 2 −2)(μ‐CCMe 2 Ph)ZnCl(THF)] ( 6 ) and [TaCl 2 ‐{μ‐C 6 H 3 (CH 2 NMe 2 ) 2 −2,6}(μ‐CCMe 2 Ph)ZnCl] ( 7 ), which have been isolated in high yields. Reaction of 7 with tmeda affords the Ta v alkylidene complex [TaCl(=CHCMe 2 Ph){C 6 H 3 (CH 2 N(Me)CH 2 )−2‐CH 2 NMe 2 )‐6}] ( 8 ), which shows catalytic activity in the ring‐opening metathesis polymerization of norbornene.