Influence of the Substituents on the Chemical Behaviour of P Rich Silylphosphanes

Abstract At first I will cover our investigations on the formation of transition metal complexes with variously substituted heptaphosphanortrkyclanes. The formation of transition metal complexes of R3P7 (R = Et, iPr) with Cr(CO)5 THF or Cr(CO)4NBD considerably changes the electronic conditions in the P7 skeleton. Comparable effects can be expected when using various substituents R. To study these dependencies the behaviour of (Me3Si)3P7, iPr2(Me3Si)P7 (tBu2P)3P7 and (tBu3Si)3P7 in reactions with the chromium carbonyls was in-vestigated.