STRUCTURES OF LOHEPTENYLIDENE-(2,4,6-TRI-T-BUTYLPHENYL)PHOSPHINE AND FLUORENYLIDENE-(2,4,6-TRI-T-BUTYLPHENYL)PHOSPHINE AND THEIR REACTIONS WITH SULFUR

Dibenzocycloheptenylidene (2,4,6-tri-t-butylphenyl)-phosphine and fluo renylidene (2,4,6-tri-t-butylphenyl)-phosphine were prepared by the re actions of lithium silylphosphide with benzosuberenone and fluorenone, respectively. The reactions of the phosphines with sulfur were carrie d out to compare the results with those of the corresponding diphenyl derivative, and the new findings are discussed in terms of steric hind rance based on the results of the X-ray crystallographic analyses for dibenzocycloheptenylidenephosphine and its sulfide and the computation al structure for the fluorenyl derivative. (C) 1997 John Wiley & Sons, Inc.