Syntheses and Structures of Diplatinum Hexatriynediyl Complexes, in Which the sp Carbon Chains Are Shielded by sp3 Carbon Chains

When trans,trans -(C 6 F 5 )( p -tol 3 P) 2 Pt(C⋮C) 3 Pt(P- p -tol 3 ) 2 (C 6 F 5 ) and Ar 2 P(CH 2 ) m PAr 2 ( m /Ar = 8/ p -tol, 10/Ph, 11/Ph, 12/Ph, 14/ p -tol) are reacted, p -tol 3 P is displaced to give products in which the diphosphines span the platinum end groups. One crystal structure ( m = 14) shows a double-helical conformation in which the sp 3 carbon chains twist around the sp chain, and others ( m = 10, 11) show nonhelical conformations with lateral shielding of the sp chain.