FURTHER-STUDIES ON THE DEPENDENCE OF THE BARRIERS FOR GEAR SLIPPAGE ON THE JOINT GROUP IN BIS(9-TRIPTYCYL)X TYPE MOLECULES - BIS(9-TRIPTYCYL)PHOSPHINE, THE MISSING LINK IN THE SERIES ALONG THE 3RD ROW OF THE PERIODIC-TABLE

Bis(9-triptycyl)phosphines have been prepared. The two tortional degre es of freedom about the bonds from the bridgehead carbons to the phosp horus correlate in such a strength as to make it just possible to sepa rate phase isomers under ambient conditions. The barrier for the loss of correlation has been accurately determined through the kinetics of the interconversion of the meso and dl isomer of bis(2-chloro-9-tripty cyl)phosphine.( Delta H double dagger = 24.0 +/- 0.1 kcal/mol, Delta S double dagger = -4.2 +/- 0.2 e.u.)