Novel Hemilabile (Phosphinoalkyl)arene Ligands: Mechanistic Investigation of an Unusual Intramolecular, Arene−Arene Exchange Reaction
作者:Elizabeth T. Singewald、Xiaobo Shi、Chad A. Mirkin、Susan J. Schofer、Charlotte L. Stern
DOI:10.1021/om960114c
日期:1996.6.25
The novel, hemilabile (phosphinoalkyl)arene ligands ArX(CH2)(2)PPh(2) (1a, Ar = C6H5, X = O; 1b, Ar = C6H5, X = CH2; 1c, Ar = FC6H4, X = CH2) were synthesized and complexed to Rh(I) to form the bis(phosphine), eta(6)-arene piano stool complexes [(eta(6):eta(1)-ArX(CH2)(2)PPh(2))Rh(eta(1)-ArX(CH2)(2)PPh(2))]BF4 (2a-c). Complexes 2a-c were fully characterized in solution, and complex 2a was characterized by single-crystal X-ray diffraction methods. Two of these complexes, 2a,c, undergo an unusual, degenerate eta(6)-arene, free arene exchange reaction which was studied by 2-D NMR EXSY experiments. A mechanism for the exchange reaction of 2a which involves the formation of a square planar, cis-phosphine, cis-ether Rh(I) complex, [Rh(eta(2)-PhO(CH2)(2)PPh(2))(2)]BF4 (13), is proposed.