INTRAMOLECULAR COORDINATION BETWEEN MAGNESIUM AND OXYGEN IN CYCLIC ORGANOMAGNESIUM COMPOUNDS

Article abstract of DOI:10.1016/S0022-328X(00)86788-1

Association measurements in THF solution reveal that cyclic organomagnesium compounds capable of intramolecular coordination between magnesium and a suitably located oxygen atom in the ring exist exclusively as monomers in THF solution, whereas their oxygen-free analogues have a high tendency to dimerize; 1-oxa-5-magnesacyclooctane (I), 1-oxa-6-magnesacyclodecane (II), its dibenzoanalogue III, and the corresponding di-Grignard reagents IIB and IIIB were investigated.A thermochemical investigation of I-III yielded more quantitative information; the intramolecular coordinative O-Mg bond has been found to be stronger than the intermolecular bond to THF.The ring strain in these compounds is discussed.