Question

confused about factors that affect insertion rates. According to Crabtree, "steric bulk in the L_n ligand set of L_nM(Me)(CO) accelerates insertion, no doubt because the acetyl in the L_nM(COMe) product, occupying one coordination site, is far less bulky than the alkyl and carbonyl, occupying two sites in the starting complex, L_nM(Me)(CO)". I understand the concept of "2 ligands becoming one", which results in relief of steric crowding. But wouldn't that depend on how bulky L_n is? Isn't it possible that a ligand is so bulky it occupies more space than two small separate ligands?

Answer 1