η²-COORDINATION OF CHLOROBENZENES TO RHENIUM FRAGMENT Cp*Re(CO)2: CHEMICAL AND PHOTOCHEMICAL SYNTHESES OF Cp*Re(CO)2(η²-C6H6-nCl n)

Abstract

The complexes Cp*Re(CO) 2 (h 2 -C 6 H 6-n Cl n ), n = 4, (5,6-h 2 -1,2,3,4-C 6 H 2 Cl 4 ) 2a; n = 3, (5,6-h 2 -1,2,4-C 6 H 3 Cl 3 ) 2b; n = 2, (2,3-h 2 -1,4-C 6 H 4 Cl 2 ) 2c and (4,5-h 2 -1,3-C 6 H 4 Cl 2 ) 2d, have been conveniently prepared by two alternative procedures: Directly, by the photochemical reaction of Cp*Re ( C NMR spectroscopy. The 1 H NMR spectra of the two derivatives containing dichlorobenzene (2c and 2d) indicate that a rapid exchange occurs between the hydrogen atoms on the coordinated carbons and those on the non-coordinated carbons.