Reactivity of dipyrimidyldiselenides with [M(PPh3)(4)] and 2-pyrimidylchalcogenolates with [MCl2(diphosphine)] (M = Pd or Pt)

Oxidative addition reactions of {SeC4H(4,6-R)(2)N-2}(2) with [M(PPh3)(4)] (M Pt or Pd) in benzene afforded complexes of composition, [Pt{SeC4H(4,6-R)(2)N-2}(2)(PPh3)(2)] (1) and [Pd{eta(2)-SeC4H(4,6-R)(2)N-2} {SeC4H(4,6-R)(2)N-2}(PPh3)] (3) (R H or Me). The former when left in solution dissociated to [Pt {eta(2)-SeC4H(4,6-R)(2)N-2}{SeC4H(4,6-R)(2)N-2}(PPh3)] (2) and PPh3. Treatment of [PtCl2((PP)-P-boolean AND)] ((PP)-P-boolean AND = dppe or dppp) and NaEC4H(4,6-R) 2N2 (for E/R Se/H/Me or Te/Me) gave mononuclear complexes [Pt{EC4H(4,6-R)(2)N-2}(2)((PP)-P-boolean AND)] (4 and 6) (R H or Me, PXP dppe or dppp) which on leaving for recrystallization in dichloromethane/CDCl3 solution resulted in trinuclear chalcogenido-bridged complexes [Pt-3(mu-E)(2)((PP)-P-boolean AND)(3)]center dot 2Cl (E Se or Te) (6). The latter were also formed when [PtCl2((PP)-P-boolean AND)] ((PP)-P-boolean AND = dppe or dppp) was treated with sodium 2-pyrimidyltellurolate. The substitution reactions between [PdCl2((PP)-P-boolean AND)] ((PP)-P-boolean AND = dppe or dppp) and NaEC4H(4,6-R)(2)N-2 (E = Se or Te; R = H or Me) afforded chalcogenido-bridged trinuclear complexes, [Pd-3(mu-E)(2)(PXP)(3)]2Cl (7) ((PP)-P-boolean AND = dppe or dppp). These complexes were characterized by elemental analyses and NMR (H-1, P-31, Se-77, Te-125, Pt-195) spectroscopy. The molecular structures of [Pt(SeC4H3N2)(2)(PPh3)(2)] (1a) and [Pd{eta(2)-SeC4H3N2}{SeC4H3N2}(PPh3)] (3a) were established by single crystal X-ray diffraction analyses. Metal atom in these complexes acquires a distorted squareplanar configuration. (C) 2012 Elsevier B. V. All rights reserved.