Half sandwich complexes of Ru(II) and complexes of Pd(II) and Pt(II) with seleno and thio derivatives of pyrrolidine: Synthesis, structure and applications as catalysts for organic reactions

The reactions of PhSe, PhS and Se-2 with N-{2-(chloroethyl)}pyrrolidine result in N-{2-(phenylseleno) ethyl}pyrrolidine (L1), N-{2-(phenylthio) ethyl}pyrrolidine (L2), and bis{2-pyrrolidene-N-yl) ethyl selenide (L3), respectively, which have been explored as ligands. The complexes [PdCl2(L1/L2)] (1/7), [PtCl2(L1/L2)] (2/8), [RuCl(eta(6)-C6H6)(L1/L2)][PF6] (3/9), [RuCl(eta(6)-p-cymene)(L1/L2)][PF6] (4/10), [RuCl(eta(6)-p-cymene)(NH3)(2)][PF6] (5) and [Ru(g eta(6)-p-cymene)(L1)(CH3CN)][PF6](2) center dot CH3CN (6) have been synthesized. The L1-L3 and complexes were found to give characteristic NMR (Proton, Carbon-13 and Se-77). The crystal structures of complexes 1, 3-6, 9 and 10 have been solved. The Pd-Se and Ru-Se bond lengths have been found to be 2.353(2) and 2.480(11)/2.4918(9)/2.4770(5) angstrom, respectively. The complexes 1 and 7 have been explored for catalytic Heck and Suzuki -Miyaura coupling reactions. The value of TON has been found up to 85 000 with the advantage of catalyst's stability under ambient conditions. The efficiency of 1 is marginally better than 7. The Ru-complexes 3 and 9 are good for catalytic oxidation of primary and secondary alcohols in CH2Cl2 in the presence of N-methylmorpholine-N-oxide (NMO). The TON value varies between 8.0 x 10(4) and 9.7 x 10(4) for this oxidation. The 3 is somewhat more efficient catalyst than 9. (C) 2009 Elsevier B.V. All rights reserved.