623925-93-9Relevant academic research and scientific papers
Alkyne insertion into cis-silyl(stannyl)platinum(II) complexes
Sagawa, Takashi,Sakamoto, Yasunobu,Tanaka, Rika,Katayama, Hiroyuki,Ozawa, Fumiyuki
, p. 4433 - 4445 (2003)
A series of cis-silyl(stannyl)platinum(II) complexes have been prepared by oxidative addition of silylstannanes to Pt(cod)2 in toluene in the presence of tertiary phosphine ligands: cis-Pt(SiR3)(SnMe3)L2 [L = PMe2Ph, SiR3 = SiMe3 (1a), SiMe2Ph (1b), SiMePh2 (1c), SiPh3 (1d); SiR3 = SiMe2Ph, L = PMe3 (1e), PEt3 (1f), PMePh2 (1g)]. These complexes undergo competitive insertion of alkynes (RC≡CH) into the Pt-Sn and Pt-Si bonds under kinetic conditions to give the insertion complexes cis-Pt{C(R)=CHSnMe3}(SiR3)L2 (2) and cis-Pt(SnMe3){C(R)=CHSiR3}L2 (3), respectively. Furthermore, once 2 is formed in the reaction systems, it is converted to 3 under thermodynamic conditions. The kinetic ratio of 2 to 3 is significantly affected by the silyl and phosphine ligands as well as the alkynes employed. Thus, in the insertion of phenylacetylene, the kinetic ratio changes depending on the silyl and phosphine ligands attached to the complexes as follows: 2/3 = 0/100 (1a), 30/70 (1b), 59/41 (1c), 93/7 (1d), 36/64 (1e), 25/75 (1f), 25/75 (1g). On the other hand, in the reactions of 1b, the kinetic ratio varies with alkynes as follows: 2/3 = 12/88 (p-H2NC6H4C≡ CH), 28/72 (p-MeC6H4C≡CH), 30/70 (PhC≡CH), 46/54 (p-OHCC6H4C≡CH), 100/0 (MeO2-CC≡CCO2Me). Reasons for the variations are discussed on the basis of the insertion mechanism elucidated by kinetic investigations.
