Phosphine dissociation mediates C-H cleavage of fluoroarenes by OsH(C<inf>6</inf>H<inf>5</inf>) (CO) (P(t)Bu<inf>2</inf>Me)<inf>2</inf>

Kenton B. Renkema, Ramon Bosque, William E. Streib, Feliu Maseras, Odile Eisenstein, Kenneth G. Caulton

Producció científica: Contribució a revistaArticleRecercaAvaluat per experts

28 Cites (Scopus)

Resum

OsH(Ph)(CO)L2 (L = p(t)Bu2Me, Ph = C6H5) is synthesized and studied by spectroscopic and DFT (B3LYP) calculations. It forms 1:1 adducts with CO or MeCN, but D2 causes reductive elimination of C6H6. Reaction with C6D6 gives exclusively OsD(C6D5)(CO)L2. Lack of conversion of OsD(C6H5)(CO)L2 to OsH(C6H4D)(CO)L2 under the same conditions indicates that zerovalent Os(η2-C6H5D)(CO)L2 is not kinetically relevant. DFT calculations confirm that an η2-arene complex is not accessible and also show that the dissociative reductive elimination of arene is a high energy process. Reaction of OsH(Ph)(CO)L2 with fluorinated arenes, HAr(F) gives benzene and OsH(Ar(F))(CO)(ptBu2Me)2 (i.e., attack on the HAr(F) C-H bond), with the fastest attack involving more heavily fluorinated arenes (but C6F6 does not react) and the attack occurring preferentially at the C-H bond ortho to fluorine. DFT calculations show that the observed isomer is thermodynamically controlled. These results, isotope-labeling results, and rate suppression and exchange involving added free phosphine lead to a mechanism where reagent arene associates with OsH(Ph)(CO)L2, but benzene loss demands preliminary dissociation of phosphine from such an adduct.
Idioma originalAnglès
Pàgines (de-a)10895-10907
RevistaJournal of the American Chemical Society
Volum121
Número47
DOIs
Estat de la publicacióPublicada - 1 de des. 1999

Fingerprint

Navegar pels temes de recerca de 'Phosphine dissociation mediates C-H cleavage of fluoroarenes by OsH(C<inf>6</inf>H<inf>5</inf>) (CO) (P(t)Bu<inf>2</inf>Me)<inf>2</inf>'. Junts formen un fingerprint únic.

Com citar-ho