NMR study of N2O dissolved in liquid cyrstals

Nuclear Quadrupole Coupling Constants for N2O: Experiment and Theory

“…For N 2 O in n -hexane the 14 N relaxation times are essentially independent of the gas pressure (Table ). Also, the data obtained for 15 atm of N 2 O in n -hexane by Lowenstein and Brenman at approximately 1.79 T (5.5 MHz for 14 N) are in good agreement with our data obtained at 8.48 T (26.1 MHz for 14 N), indicating that chemical shielding anisotropy is not an important relaxation mechanism for either nitrogen of N 2 O in solution. Bhattacharyya and Dailey have obtained Δσ values of 369 ± 15 and 512 ± 10 ppm for the terminal and central nitrogen, respectively.…”

“…Assuming C Q ( 14 N t ) = 0.774 MHz, C Q ( 17 O) was estimated to be 12.4 ± 1.2 MHz for nitrous oxide. The value was obtained by assuming both the terminal nitrogen and the oxygen nuclei relax exclusively by the quadrupolar relaxation mechanism. c From ref . d This sample was 3.1 atm in 15 N 14 NO and 2.6 atm in 14 N 15 NO. The 15 N T 1 values exceeded 30 s and more likely 50 s. …”

Direct detection of nitrogen-14 in solid-state NMR spectroscopy

“…Yannoni indirectly measured the 14 N C Q and CSA from methylisocyanide dissolved in a nematic LC via the 1 H nuclei using the "spin-tickling" method [150]. Other authors later directly observed 14 N quadrupolar splittings from various small molecules in different LC phases [151][152][153][154][155][156]. Studies of tetrahedral ions such as ammonium and tetramethylammonium dissolved in lyotropic mesophases resulted in observable quadrupolar splittings of several hundred Hz, indicating both a distortion of the ion and contributions to the EFG from surrounding ionic charges and molecular dipoles [157][158][159] the nematic phase of para-azoxyanisole [163].…”

Nitrogen nuclear magnetic resonance spectroscopy in inorganic, organometallic, and bioinorganic chemistry

“…For larger molecules, sharper lines are obtained by reduction in sample viscosity, as by the use of mobile solventsz2 or of higher temperatures. [22][23][24][25][26] The high mobility of perfluoro compounds, for example, is advantageous in 14N work. minimum distance of water from the ion, cHzO the concentration of water molecules, and T, the correlation time of the ion, assumed short on the NMR time scale.1°J3 /3 stands for P(l -7-1, where P is the polarizability of the medium and ym the Sternheimer antishielding factor (equal to about -4 for NH4+ in ammonium alum20).…”