Bridge cleavage of transition metal dimers by chelating S,N ligands. X-ray crystal structure of [Pd{SPPh₂N=C(NH2)NH-S,N}(3-C3H5)],

Deprotonation of the N-thiophosphoryl compounds Me2P(S)N=C(NH2)(2) (HL1), Ph2P(S)N=C(Me)(NH2) (HL2) or Ph2P(S)N=C(NH2)(2), (HL3) using potassium t-butoxide in thf, followed by treatment with [Rh(mu -Cl)(eta (4)-cod)](2) (cod = 1,5-cis,cis-cyclooctadiene), [Pd(mu -Cl)(eta (3)-C3H5)](2) or [RhCl(mu -Cl)(eta (5)-C5Me5)](2) affords [Rh(L-n-S,N)(eta (4)-cod)] 1-3, [Pd(L-n-S,N)(eta (3)-C3H5)] 4-6 and [RhCl(L-n-S,N)(eta (5)-C5Me5)] 7-9, respectively. The (L-n)- anions form six-membered S,N chelate rings at the metal centre, in a manner analogous with beta -diketonates and imidodiphosphinates. The complexes 1-9 have been characterised spectroscopically and by single crystal X-ray diffraction for [Pd(L-3-S,N)(eta (3)-C3H5)] 6. The molecular structure of 6 confirms S,N chelation of the (L-3)(-) anion to give a palladacycle adopting a half boat conformation. (C) 2001 Elsevier Science Ltd. All rights reserved.