The synthesis and reactivity of organoiridium complexes containing metal-heteroatom bonds

Abstract

Irradiation of Cp*(PMe{sub 3})IrH{sub 2}(1) in tert-butylamine and tert-butanol gives exclusively the products of C-H, rather than N-H or O-H, insertion Cp*(PMe{sub 3})Ir(CH{sub 2}CMe{sub 2}XH)H (2, X = NH; 3, X = 0). These oxidative addition products can be converted to the 2-aza- and 2-oxametallacyclobutane complexes by replacement of iridium-bound hydride by chloride using CHCl{sub 3}, followed by treatment with the hindered base KN(TMS){sub 2}. The monomeric methylene complex Cp*(PMe{sub 3})Ir(CH{sub 2}) (2) is produced upon photolysis of the 2-oxametallacycle Cp*(PMe{sub 3})Ir(CH{sub 2}CMe{sub 2}O) (1) in toluene solution at low temperature, and is found to be indefinitely stable in solution below {minus}40 {degrees}C. The methylene carbon in 2 is quite basic; the reaction of 2 with a variety of organic acids is described. Complex 2 also reacts with non-protic reagents. The synthesis of a variety of iridium and rhodium mono- and bis-thiolate complexes is described. These molecules can be prepared by exchange reactions of organic thiols with Cp*(PMe{sub 3})Ir(OEt)H (6) or by nucleophilic displacement of metal-bound chloride by sodium alkyl thiolates. Several of these complexes have been characterized by x-ray crystallography. A preliminary study on the chemistry of these compounds is presented which shows that reaction can take place at either the sulfur atom or the metal center.