(η3+ -Benzyl)(η4 -cyclooctadien)rhodium(I)-Komplexe / (η3 -Benzyl)(η4 -cyclooctadiene)rhodium(I) Complexes

Abstract

Abstract Reactions of [(COD)RhCl]2 (2) (COD = 1,5-cyclooctadiene) with i-C3H7MgBr in ether and styrene or o-methylstyrene lead to formation of the complexes [(COD)Rh(η3 -7-methyl-benzyl)] (3) and [(COD)Rh(η3 -6,7-dimethylbenzyl)] (4), respectively. 4 was characterized by X-ray analysis. With β-methylstyrene or allylbenzene [(COD)Rh(η3 -7-ethylbenzyl)] (5) is formed; the latter case leads to precedent isomerisation of allylbenzene to β-methyl-styrene. On the other hand no η3 -benzylrhodium complexes could be isolated by reactions of 2 with a-methylstyrene, 2,4-dimethylstyrene, 2,6-dimethylstyrene or 2,4,6-trimethyl-styrene. The steric reasons for this behaviour are discussed.