New Tridentate Carbamoylmethylphosphine Oxides: Synthesis and NMR Spectra

Amidation of diphenylphosphorylacetic acid gave tridentate ligands Ph 2 P(O)CH 2 CON(R)· CH 2 CH 2 P(O)Ph 2 (R = Me, Bu, Oct) containing a phosphoryl group in the amide moiety. According to the 1 H, 13 C{ 1 H}, and 31 P{ 1 H} NMR spectra, the synthesized compounds exist in CDCl 3 solution as two conformers at the ratios of ~2.5 : 1 (R = Me), 2.6 : 1 (R = Bu), and 3.0:1 (R = Oct). These ratios do not change with temperature (heating or cooling).