SOLVOLYSIS AND DISSOCIATION OF 7-SUBSTITUTED NORBORNADIENE GROUP-6B METAL TETRACARBONYLS

Chromium-, molybdenum-, and tungsten-tetracarbonyl complexes of 7-chloronorbornadiene and chromium- and molybdenum-tetracarbonyl complexes of 7-benzoyloxynorbornadiene have been prepared. Solvolysis of the 7-chloro compounds in 80% aqueous acetone at 25° proceeds via a prior rapid dissociation to a solvated metal tetracarbonyl species and 7-chloronorbornadiene, which then solvolyzes. These norbornadiene complexes, which are undissociated in deuteriochlorof orm, have been shown to dissociate reversibly in acetone and aqueous-acetone mixtures by nmr spectroscopy. Per cent dissociation of norbornadiene metal carbonyl complexes decreases in the series Mo >Cr, W> Fe and increases with increasing electron pair donor power of the sol ent. The 7-substituted norbornadiene metal tetracarbonyls aremore highly dissociated than their corresponding parent norbornadiene complexes. © 1969, American Chemical Society. All rights reserved.