Synthesis and Conformational Studies of (Diphenylphosphinoamino)-cyclodiphosph(III)azanes

Article abstract of DOI:10.1039/DT9820001503

A series of 2,4-bis(diphenylphosphinoalkylamino)-1,3-di-t-butylcyclodiphosph(III)azanes, <(Ph2P)RNPNBu^t>2 i or Bu^t (cis-isomers)>, have been prepared by the reactions of N-lithiated alkyl-N-(diphenylphosphino)amines, N(PPh2)(R)(Li), with 2-cis-4-dichloro-1,3-di-t-butylcyclodiphosph(III)azane, (ClPNBu^t)2, in benzene solution.Hydrogen-1, 13C, and 31P n.m.r. spectroscopy show that these compounds are cyclodiphosph(III)azanes rather than phosph(III)azanes, (Ph2P)RNP=NBu^t, in solution, and variable temperature 31P n.m.r. date have enabled the preferred conformations of the exo-P-N-P skeletons to be identified.In the case of <(Ph2P)RNPNBu^t>2 (R=Prⁱ and Bu^t) more than one conformer can be distinguished at sub-ambient temperatures.