CYCLIC POLYSILANES. XIX. A TEMPERATURE STUDY OF REDISTRIBUTION EQUILIBRIA BETWEEN PERMETHYLCYCLOPOLYSILANES

Article abstract of DOI:10.1016/S0022-328X(00)86662-0

Equilibria among the cyclic compounds (Me2Si)n where n=5, 6 and 7 have been studied between 30-58 deg C.Thermodynamic values for the redistribution reactions between pairs of compounds are, for n=5 -> 6, ΔH=-18 kcal/mole, ΔS=-20 cal/deg. mole; for n=7 -> 6, ΔH -3, ΔS +33; for n=7 -> 5, ΔH +18, ΔS +51.The enthalpies indicate that the stabilities of the rings increase in the order (Me2Si)5 < (Me2Si)7 < (Me2Si)6.The differences are smaller than corresponding differences among the cycloalkanes, probably because the silicon compounds are less affected by steric repulsions and angle strain.