Alkynylbis(alkylidynyl)phosphines: {LnM[triple bond, length as m-dash]C}2PC[triple bond, length as m-dash]CR

Abstract

Sequential treatment of [M([triple bond, length as m-dash]CBr)(CO)2(Tp*)] (M = Mo, W; Tp* = hydrotris(dimethylpyrazolyl)borate) with nBuLi, RPCl2 and LiC[triple bond, length as m-dash]CSiMe3 affords [M{[triple bond, length as m-dash]CPR(C[triple bond, length as m-dash]CSiMe3)}(CO)2(Tp*)] (R = Ph, Cy) which are readily desilylated (TBAF) to provide the parent ethynyl derivatives [M{[triple bond, length as m-dash]CPR(C[triple bond, length as m-dash]CH)}(CO)2(Tp*)]. Alternatively, treating [W([triple bond, length as m-dash]CBr)(CO)2(Tp*)] with nBuLi, 1/2 PCl3 and LiC[triple bond, length as m-dash]CR' affords the alkynylbis(alkylidynyl)phosphines [R'C[triple bond, length as m-dash]CP{C[triple bond, length as m-dash]W(CO)2(Tp*)}2] (R' = C6H5, C6H4Me-4, CMe3, SiMe3) and again the silyl derivative may be desilylated to the parent (R' = H) which is readily converted to an arsino derivative (R' = AsPh2). These novel architectures present new linkages for bridge-assisted polymetallic assembly.