Triisopropylsilyl (TIPS) Alkynes as Building Blocks for Syntheses of Platinum Triisopropylsilylpolyynyl and Diplatinum Polyynediyl Complexes

Hay oxidative cross coupling (O2/CuCl/TMEDA) of trans-(p-tol)(p-tol3P)2Pt(C≡C)2H (PtTC4H) and excess H(C≡C)2Si-i-Pr3 (TIPSC4H) gives PtTC8TIPS (55%). Subsequent addition of n-Bu4N+F– and repetition of the Hay protocol yields PtTC12TIPS (56%) and the byproduct trans-i-Pr3Si(C≡C)2(p-tol3P)2Pt(C≡C)6Si-i-Pr3 (TIPSC4PtC12TIPS, 5%); another cycle gives PtTC16TIPS (13%). Analogous cross couplings of trans-(C6F5)(p-tol3P)2Pt(C≡C)2H (PtFC4H) and excess TIPSCxH yield PtFC6TIPS (x = 2, 58%) and PtFC8TIPS (x = 4, 23%). Each is treated with n-Bu4N+F–, and repetition of the Hay protocol with TIPSC4H gives PtFC10TIPS (58%) and PtFC12TIPS (47%). When the Hay conditions are applied to PtFCxTIPS (x = 6, 8, 10, 12) without a cross-coupling partner, homocoupling to PtFC2xPtF occurs (68–99%). The reaction of trans-(p-tol3P)2PtCl2 and TIPSC4H (4.5 equiv; cat. CuI, CH2Cl2/HNEt2) yields TIPSC4PtC4TIPS (95%). Hay cross coupling of HC4PtC4H and excess TIPSC4H gives TIPSC4PtC4TIPS (6%), TIPSC4PtC8TIPS (12%), TIPSC8PtC8TIPS (10%), T...