Crystal structure and exchange coupling of a novel binuclear Palladium(I) complex

GUSTAVO A. ECHEVERRÍA; FLAVIO SIVES; OSCAR E. PIRO; SUSANA TARULLI; OSCAR V. QUINZANI; RICARDO M. FERULLO; NORBERTO J. CASTELLANI

Bahía Blanca

Congreso; Reunión de la Asociación Argentina de Cristalografía; 2008

Universidad Nacional del Sur

Despite the continuous interest in molecular or polymeric compounds containing the Pd2(diphos)22+ fragment, there is scarce information on LPd(μ-dppm)2PdL’ structures, where the L, L’ ligands are 4-mercapto-pyridine molecules, Br, or Cl and 2-vinylpyridine and to the best of our knowledge no magnetic studies have been so far reported in the literature. Based on the well-studied binuclear Cu(II): 3d9 (s=1/2) complexes, we infer Pd(I)···Pd(I)exchange interaction giving rise to a diamagnetic (S=0) ground state and to a paramagnetic(S=1) excited state. We attempted to test this hypothesis by magnetic susceptibility measurements in the 10-390 K range, employing a SQUID magnetometer. The results showed diamagnetic behaviour up to 390 K hence suggesting a relatively large exchange coupling, much larger than the values of about 400 K found for lantern-like Cu(II) binuclear complexes. This is sustained by preliminary DFT calculations of the singlet-triplet energy splitting.