Structural variations in nickel, palladium, and platinum complexes containing pyrimidyl N-heterocyclic carbene ligand

Nickel(II), palladium(II), and platinum(II) complexes of 2-(3-mesitylimidazolylidenyl) pyrimidine (L), [Ni-2(mu-Cl)(2)(L)(4)][Ag2Cl4] (3), [Ni-2(mu-I)(2)(L)(4)][NiI(L)(2)(CH3CN)](2)[Ag4I8] (4), [PdCl2(L)] (5), [PdI2(L)] (6), and [PtCl(L)(2)][AgCl2] (7) have been obtained from the carbene transfer reactions of [Ag(L) Cl] (2). These complexes have been fully characterized by spectroscopic methods and single-crystal X-ray structure analyses. The mono(carbene) palladium and bis(carbene) platinum complexes display normal square -planar structures. Nickel complexes 3 and 4 are rare examples of paramagnetic nickel(II) complexes of N-heterocyclic carbenes having octahedral geometry. (C) 2008 Elsevier B. V. All rights reserved.