Synthesis, spectroscopic and structural studies on transition metal carbonyl complexes of cyclic di- and tetra-selenoether ligands

摘要

Reaction of [M(CO)_4(nbd)] (M=Cr or Mo, nbd=norbornadiene) or [W(CO)_4(TMPA)] (TMPA=N, N, N', N'-tetramethyl-1, 3-propanediamine) with [8] aneSe_2 (1, 5-diselenacyclooctane) yielded the cis-disubstituted tetracarbonyl species [M(CO)_4([8]aneSe_2)] (M=Cr, Mo or W). The complexes [M'X(CO)_5] (M'=Mn, X=Cl, Br or I; M'=Re, X=Cl or Br) reacted similarly with [8] aneSe_2 to give fac-[M'X(CO)_3([8]aneSe_2)] in high yield. Infrared and multinuclear NMR spectroscipic studies confirmed these assignments and indicated a single species in solution; #delta#(~(55)Mn) lies in the same range as observed for other fac-[MnX(CO)_3(diselenoether)] complexes, while for all of the compounds #delta#(~(77)Se) is to low frequency of [8] aneSe_2 itself (#delta# 137). Crystal structures of [W(CO)_4([8]aneSe_2)], [MnBr(CO)_3([8]aneSe_2)] and [ReBr(CO)_3([8]aneSe_2)] show the cyclic diselenoether chelating and adopting a chair-boat conformation. The compounds [16]aneSe_4 (1, 5, 9, 13-tetraselenacyclohexadecane) and L (1, 6-diselena-3, 4-benzocyclononane) reacted with the metal (II) species [{MoBr_2(CO)_4}_2] or [MI_2(CO)_3(NCMe)_2] in CH_2Cl_2 solution to give seven-co-ordinate [{MoX_2(CO)_3}_2([16]aneSe_4)], [WI_2(CO)_3([16]aneSe_4)], [MoX_2(CO)_3(L)] and [WI_2(CO)_3(L)], although these species decompose rapidly in co-ordinating solvents. Reaction of [16] aneSe_4 with two molar equivalents of [M'Cl(CO)_5] yielded the dinuclear complex [{MnCl(CO)_3}_2([16]aneSe_4)] (in which the tetraselenoether is thought to bind in a bidentate manner to each Mn) and the mononuclear complex [ReCl(CO)_3([16]aneSe_4)] (which is thought to involve bidentate ligation to [16] aneSe_4 with two free Se donors). The cationic species fac-[Mn(CO)_3(#eta#~3-[16]aneSe_4)]CF_3SO_3 was generated by treatment of [MnCl(CO)_5] with AgCF_3SO_3 in Me_2CO followed by addition of [16]aneSe_4.