Direct transformation of six- to three-coordinate phosphorus in p-tert-butylcalix[4]arene; the first X-ray crystal structure of a hypervalent main group atom bound to a calixarene

Abstract

Removal of dimethylamine from the zwitterionic six-coordinate phosphorus species p-fert-butylcalix[4]areneP(H)NHMe₂1 leads to the three-coordinate derivative p-tert- butylcalix[4]arene(H)P 4; the X-ray structure of Li[p-tert-butylcalix[4]areneP(H)NMe₂]3 gives an insight as to why no pentacoordinate species is observed.