Vibrational assignment and rotational isomerism in some simple organic phosphates

Conformational properties of trimethyl phosphate monomer

“…P-O-(C) stretching [10], m a PO 3 [17], m a (P-O) 3 [14], m a (P-O 3 ) [9]. This diversity of descriptions reflects the complicated nature of the vibrations in question.…”

“…The structures of possible conformers are usually addressed in terms of their overall symmetry (C 3v , C 3 , C s and C 1 ). In 1957, Mortimer observed [10] the splitting of the P@O stretching band in the infrared spectra of liquid TMP. He explained this fact in terms of more than one rotational isomer.…”

“…Practically, all subsequent experimental studies observed doublets in the spectra of liquid TMP or its solutions, the splitting being systematically interpreted in terms of conformational multiplicity. In the discussion of the vibrational assignments, Mortimer considered the symmetry of both isomers to be at least approximately C 3 (one of them being C 3v ) [10]. The assumption of existence of a threefold symmetry axis appeared in many subsequent studies [20,[25][26][27].…”

“…In fact, the problem of conformational isomerism in TMP has been addressed many times during several decades. The molecule has been extensively studied in the past using vibrational spectroscopy in solutions [7][8][9][10][11][12][13][14][15][16][17][18][19], in gaseous [18,20] and solid [17][18][19] phases, and isolated in cryogenic matrices [19][20][21][22][23][24]; NMR spectroscopy [14,15,25]; electron diffraction [26]; dipole moments and Kerr constants methods [7,27]; dielectric loss spectroscopy [28]; and theoretically [14,21,[29][30][31]. And this big list of references is far from being complete.…”

Synthesis and characterization of carbamoylphosphonate monomer and its copolymer with styrene. II

“…The split of the phosphoryl absorption peak was initially reported to be caused by rotational isomerism. 17 The rotation about the P-ligand bond could lead to two or more conformations in which the interatomic distance between the phosphoryl oxygen and various parts of the ligand is substantially different. 18 It is clear from the results of this study, and those previously reported from this laboratory, 19 that a These two absorptions of phosphoryl bands are among several overlapping bands in the region from 1400 to 1100 cm 01 .…”