Copper(I) complexes of cis,cis-1,3,5-tris(mesitylideneamino)cyclohexane ligands: synthesis, structure and substrate selectivity

The new sterically encumbered facially coordinating N-3-donor ligand cis,cis-1,3,5-tris(mesitylideneimino)cyclohexane (L1) has been synthesised. Reaction with [Cu(NCCH3)(4)] PF6 gives [Cu(L1)NCCH3]PF6 (1), the bound acetonitrile being labile and readily replaced by CO to yield [Cu(L1)CO]PF6 (2); both 1 and 2 have been structurally characterised. Complexes 1 and 2 do not undergo a substitution reaction with ethylene. This is in contrast to the related bidentate ligand complexes [Cu(L2)NCCH3]BF4 (3) or [Cu(L2)CO]BF4 (4) (L2 = 1,2-bis(mesitylideneamino)cyclohexane) which rapidly form the ethylene complex under the same conditions.