Transition metal polyhydride complexes. 11. Mechanistic studies of the cis to trans isomerization of the Iridium(III) Dihydride Ir(H)2(CO)L (L = C6H3(CH2P(H)2)2) Academic Article uri icon

abstract

  • Density functional theory (B3LYP) has been used to investigate the mechanism of the cis-trans isomerization in Ir(H)2(CO)L (L = C6H3(CH2P(H2))2), a model for Ir(H)2(CO)L (L = C6H3(CH2P(i-Pr2))2. This complex is initially formed as the cis isomer by bubbling H2through a benzene solution of Ir(CO)L at room temperature. Over period of 18 h at 90C, the cis isomer quantitatively converts to the trans isomer (Organometallics 1997, 16, 3786). Five possible mechanisms are examined in detail: (i) CO dissociation and reassociation; (ii) CO migratory insertion into the Ir-H bond and subsequent elimination; (iii) Ph-H reductive elimination to an arene intermediate and subsequent oxidative addition; (iv) phosphine dissociation, complex rearrangement, and phosphine reassociation; and (v) nondissociative trigonal twist. The preferred mechanism involves two consecutive trigonal twists in which the complex passes through a distorted octahedral intermediate.

published proceedings

  • Organometallics

author list (cited authors)

  • Li, S., & Hall, M. B.

complete list of authors

  • Li, S||Hall, MB

publication date

  • December 1999