A theoretical study on CO2 insertion into an M(bond)H bond (M = Rh and Cu)

✍ Scribed by Shigeyoshi Sakaki; Yasuo Musashi

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 797 KB
• Volume: 57
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1996)57:3<481::aid-qua22>3.0.co;2-5

✦ Synopsis

Insertion of CO, into the transition metal-hydride bond of [RhmH,(PH,),]+, Cu'H(PH,),, and Rh'H(PH,), was theoretically investigated with ab initio MO/MP4, SD-CI, and CCD methods. The geometries of reactants, transition states (TS), and products were optimized at the Hartree-Fock level, and then M P ~, SD-CI, and CCD calculations were performed on those optimized structures. The TS of the CO, insertion into the Cu'-H bond is the most reactantlike, while the TS of the CO, insertion into the Rh"'-H bond is the most productlike. The activation energy (E,) and the reaction energy (A E ) were calculated to be 6.5 and -33.5 kcal/mol for the CO, insertion into the Cu'-H bond, 21.2 and -7.0 kcal/mol for the CO, insertion into the Rh' -H bond, and 51.3 and -1.1 kcal/mol for the RhIn-H bond at the SD-CI level, where negative A E represents exothermicity. These results are discussed in terms of the M-H bond energy and the trans-influence of the hydride ligand.