A phase based approach to insulated molecular wires: Diplatinum octatetraynediyl complexes bearing fluorous trialkylphosphine ligands

Reactions of [(tetrahydrothiophene)Pt(C 6 F 5 )μ-Cl] 2 and fluorous phosphines P((CH 2 ) m R fn ) 3 (R fn  = (CF 2 ) n−1 CF 3 ; m/n  =  a, 2/8; b, 3/8; c, 3/10) afford the chloride complexes trans -(C 6 F 5 )((R fn (CH 2 ) m ) 3 P) 2 PtCl ( 8a - c, 40–74%), which upon treatment with butadiyne and CuI (cat.) in HNEt 2 /CF 3 C 6 H 5 give trans -(C 6 F 5 )((R fn (CH 2 ) m ) 3 P) 2 Pt(C C) 2 H ( 9a - c, 44–64%). Subsequent reactions with oxygen and CuCl/TMEDA in acetone yield the title complexes trans,trans -(C 6 F 5 )((R fn (CH 2 ) m ) 3 P) 2 Pt(C C) 4 Pt(P((CH 2 ) m R fn ) 3 ) 2 (C 6 F 5 ) ( 10a - c, 35–52%). All platinum complexes exhibit CF 3 C 6 F 11 /toluene partition coefficients of >99:<1. The crystal structure of 8b shows that the perfluoroalkyl groups segregate into fluorous domains. It was therefore thought that the perfluoroalkyl groups in 10a - c would aggregate about the polyynediyl chain. However, these adducts could not be crystallized. Electrochemical oxidations of 10a - c give radical cations that are much less stable than trialkyl and triarylphosphine analogs.