Measurements of phosphorus-31 chemical shielding anisotropies and signs of spin-spin coupling constants of oriented PX(CH3)3 systems in smectic A solution

31P solid state nuclear magnetic resonance principal values of the chemical shift tensors of phosphane oxides, phosphane sulphides and phosphane selenides

“…studies on phosphates [22,23,8,24] and thioxophosphonates [25], and from liquid crystal N.M.R. studies on phosphanes and phosphane derivatives [11,16,17,18]. Thus, it is expected that the study of 31p chemical shift tensors could provide more chemical and structural information than the isotropic liquid shielding values.…”

“…In order to examine the influence of the geometrical factors on the principal components ~rr, the study has been essentially limited to molecules whose solid state geometry is known from X-ray diffraction (5, 1', 2', 3', 5', 6', 7', 8', 1", 5"). A few data concerning the parallel a ~ = %, and perpendicular a±= 1 (axx+ %v) components of the 31p tensor of phosphanes and derivatives have already been reported in the literature from liquid crystal studies [16,17,18] ; the z direction is as usual parallel to the threefold axis of the molecule, the x and y directions being degenerate in a plane perpendicular to the z direction. These data will be compared with the results reported here.…”

An 17O NMR and Quantum Chemical Study of Monoclinic and Orthorhombic Polymorphs of Triphenylphosphine Oxide

“…The information available from previous NMR studies on phosphine oxides, their complexes, and their derivatives has generally been restricted to the determination of isotropic 31 P and 17 O chemical shifts (CS), δ iso , and isotropic J coupling constants from solution NMR spectroscopy, − as well as δ iso ( 31 P) from 31 P magic-angle spinning (MAS) NMR spectroscopy in the solid state. − Some information on the 31 P ( I = 1/2) CS tensor is also available. − In contrast, results from 17 O ( I = 5/2) NMR spectroscopy of phosphine oxides in the solid state are lacking. The range of oxygen isotropic chemical shifts in solution is on the order of 2500 ppm with phosphine oxides generally falling in the range of 20−100 ppm. − Overviews of 17 O nuclear quadrupolar coupling constants ( C Q ), which are very sensitive to the electric field gradient (EFG) about the 17 O nucleus, are available. − Values of C Q ( 17 O) range from less than 1.0 MHz (e.g., MoO 4 2- ) to greater than 15 MHz (e.g., H 2 O 2 ).…”

“…[12][13][14][15] Some information on the 31 P (I ) 1/2) CS tensor is also available. [16][17][18][19][20][21][22][23][24][25] In contrast, results from 17 chemical shifts in solution is on the order of 2500 ppm with phosphine oxides generally falling in the range of 20-100 ppm. [26][27][28] Overviews of 17 O nuclear quadrupolar coupling constants (C Q ), which are very sensitive to the electric field gradient (EFG) about the 17 O nucleus, are available.…”