The solution structure of [Rh(COMe)(CO)2I3]– and the absence of methyl migration in [Rh2(COMe)2(CO)2I6]2–

Abstract

The observation of inequivalent CO groups at –130 °C for [Rh(COMe)(CO)₂I₃]^– is due to restricted rotation about the Rh–COMe bond with ΔG^‡ 7.6 kcal mol^–1, ²J(¹³CO,¹³CO) 59 Hz showing that the carbonyls are mutually trans; the lack of ¹³COMe/¹²CO exchange in [Rh₂(¹³CO¹³CH₃)₂(¹²CO)₂I₆]^2– demonstrates that its preparation from [Rh(¹³CH₃)(¹²CO)(¹³CO)I₃]^– is not reversible.