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

When trans,trans-(C6F5)(p-tol3P)2Pt(C⋮C)3Pt(P-p-tol3)2(C6F5) and Ar2P(CH2)mPAr2 (m/Ar = 8/p-tol, 10/Ph, 11/Ph, 12/Ph, 14/p-tol) are reacted, p-tol3P 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 sp3 carbon chains twist around the sp chain, and others (m = 10, 11) show nonhelical conformations with lateral shielding of the sp chain.