An unexpected insertion of acetone into the silicon–carbon terminus of an sp carbon chain: syntheses and structures of model monoplatinum hexatriynyl and octatetraynyl complexes

Abstract

The sequential treatment of trans -(C 6 F 5 )( p -tol 3 P) 2 PtC≡CC≡CC≡CSiEt 3 ( 2 , acetone solution) with n -Bu 4 N + F – in wet THF (to generate a PtC≡CC≡CC≡CH complex), ClSiMe 3 (fluoride ion scavenger), excess HC≡CSiEt 3 , excess O 2 , and CuCl/TMEDA (0.20–0.25 equiv in acetone; Hay cross-coupling conditions) gives trans -(C 6 F 5 )( p -tol 3 P) 2 PtC≡CC≡CC≡CC≡CSiEt 3 ( 4 , 30%), as previously reported. When an analogous reaction is conducted with SiMe 4 in place of ClSiMe 3 , the side-product trans -(C 6 F 5 )( p -tol 3 P) 2 PtC≡CC≡CC≡CC(Me) 2 OSiEt 3 is obtained (ca 28%), the structure of which is established crystallographically. For comparison, crystal structures of three related complexes, 4 , 2 , and trans -( p -tol)(Ph 3 P) 2 PtC≡CC≡CC≡CSiEt 3 , are determined.