Carbonylrhodium complexes of pyridine ligands and their catalytic activity towards carbonylation of methanol

✍ Scribed by Nandini Kumari; Manab Sharma; Pankaj Das; Dipak Kumar Dutta

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 134 KB
• Volume: 16
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/aoc.293

✦ Synopsis

The cis-[Rh(CO) 2 ClL] (1) complexes, where L = 2-methylpyridine (a), 3-methylpyridine (b), 4methylpyridine (c), 2-phenylpyridine (d), 3-phenylpyridine (e), 4-phenylpyridine (f), undergo oxidative addition reactions with various electrophiles, like CH 3 I, C 2 H 5 I, C 6 H 5 CH 2 Cl or I 2 , to yield complexes of the types [Rh(CO)(COR)ClXL] (2) (where R = CH 3 (i), C 2 H 5 (ii), X = I; R = C 6 H 5 CH 2 (iii), X = Cl) or [Rh(CO)ClI 2 L] (3) and [Rh(CO) 2 ClI 2 L] (4). The pseudo-first-order rate constants of CH 3 I addition with complexes 1 containing pyridine (g) and 2-substituted pyridine (a and d) ligands were found to follow the order pyridine >2-methylpyridine >2-phenylpyridine. The catalytic activity of complexes 1 containing different pyridine ligands (a±g) on carbonylation of methanol was studied and, in general, a higher turnover number was obtained compared with that of the well-known species [Rh(CO) 2 I 2 ] À .