Homoleptic chelating N-heterocyclic carbene complexes of palladium and nickel

Homoleptic, dicationic nickel(II) complexes with two cis-chelating N-hetero cyclic carbene ligands have been prepared via high yielding, air-stable pro cedures. Homoleptic and heteroleptic dicationic tetra(carbene) palladium(II ) analogues are accessible by the reaction of [cis-CH2(N(H)C=C(H)N(Me)C)(2) Pd(OAc)(2)] with one diazolium diiodide salt precursor or by reacting [cis- CH2(N(H)C=C(H)N(Me)C)(2)PdI2] with two equivalents of NaOAc and the corresp onding diazolium diiodide salts. H-1- and C-13-NMR as well as X-ray crystal lographic data are discussed. (C) 1999 Elsevier Science S.A. All rights res erved.