2614-35-9Relevant academic research and scientific papers
Infrared and Raman spectra, conformational stability, ab initio calculations, and vibrational assignments for methylaminothiophosphoryl difluoride
Van Der Veken,Sanders,Xiao,Durig
, p. 57 - 86 (2001)
Infrared spectra (4000-50 cm-1) of the vapor, amorphous and crystalline solids and Raman spectra (3600-10 cm-1) of the liquid with qualitative depolarization data as well as the amorphous and crystalline solids of methylaminothiophosphoryl difluoride, CH3N(H)P(=S)F2, and three deuterated species, CD3N(H)P(=S)F2, CH3N(D)P(=S)F2, and CD3N(D)P(=S)F2, have been recorded. The spectra indicate that in the vapor, liquid and amorphous solid a small amount of a second conformer is present, whereas only one conformer remains in the low temperature crystalline phase. The near-infrared spectra of the vapor confirms the existence of two conformers in the gas phase. Asymmetric top contour simulation of the vapor shows that the trans conformer is the predominant vapor phase conformer. From a temperature study of the Raman spectrum of the liquid the enthalpy difference between the trans and near-cis conformers was determined to be 368 ± 15 cm-1 (4.4l ± 0.2 kJ/mol), with the trans conformer being thermodynamically preferred. Ab Initio calculations with structure optimization using the 6-31G(d) and 6-311+G(d,p) basis sets at the restricted Hartree-Fock (RHF) and/or with full electron correlation by the perturbation method to second order (MP2) support the occurrence of near-trans (～5° from trans) and near-cis (～20° from cis) conformers. From the RHF/6-31G(d) calculation the near-trans conformer is predicted to be the more stable form by 451 cm-1 .(5.35 kJ/mol) and from the MP2/6-311+G(d,p) calculation by 387 cm-1 (4.63 kJ/mol). All of the normal modes of the near-trans rotamer have been assigned based on infrared band contours, depolarization values and group frequencies and the assignment is supported by the normal coordinate calculation utilizing harmonic force constants from the MP2/6-31G(d) ab initio calculations.
Spectroscopy and dynamics of methylamine. I. Rotational and vibrational structures of CH3NH2 and CH3ND2 in A states
Baek, Sun Jong,Choi, Kyo-Won,Choi, Young S.,Kim, Sang Kyu
, p. 11026 - 11039 (2003)
Rovibrational structures of methylamines in predissociative A states were investigated using (1+1) resonant-enhanced two-photon ionization (R2PI) spectroscopy. An internal rotor Hamiltonian including a torsional barrier was employed for the perfect match of experiment and theory. Ab initio results for structures and vibrational frequencies of methylamines at excited states were compared with the experiment.
Structural Studies on Bio-active Compounds. Part 2. The Solid-state and Solution Conformations of N-Methyl-2-nitroethenamine and Related Compounds
Gate, E. Nicholas,Meek, Michelle A.,Schwalbe, Carl H.,Stevens, Malcolm F. G.,Threadgill, Michael D.
, p. 251 - 256 (2007/10/02)
The 1H n.m.r. spectra of NN-dimethyl-2-nitroethenamine, N-methyl-2-nitroethenamine, and 2-nitroethenamine in several solvents have been analysed.In the case of the monomethyl compound, the proportions of different rotamers about the C=C and C-N bonds are found to be solvent dependent.An X-ray crystallographic study of this compound indicates inter- rather than intra-molecular hydrogen bonding in the solid; molecular orbital calculations predict three of the possible four conformers about these bonds to be of similar and much lower energy than the fourth.
Gas-Phase Ion/Molecule Isotope-Exchange Reactions: Methodology for Counting Hydrogen Atoms in Specific Organic Structural Environments by Chemical Ionization Mass Spectrometry
Hunt, Donald F.,Sethi, Satinder K.
, p. 6953 - 6963 (2007/10/02)
Ion/molecule reactions are described which facilitate exchange of hydrogens for deuteriums in a variety of different chemical environments.Aromatic hydrogens in alkylbenzenes, oxygenated benzenes, m-toluidine, m-phenylenediamine, thiophene, and several polycyclic aromatic hydrocarbons and metallocenes are exchanged under positive ion CI conditions by using either D2O, EtOD, or ND3 as the reagent gas.Aromatic hydrogens, benzylic hydrogens, and hydrogens on carbon adjacent to carbonyl groups suffer exchange under negative ion CI conditions in ND3, D2O, and EtOD, respectively.A possible mechanism for the exchange process is discussed.
Methylamine-Deuterium Isotope Exchange Equilibria in the Gaseous and Liquid Phases
Rolston, J. H.,Hartog, J. den,Butler, J. P.
, p. 2170 - 2179 (2007/10/02)
The deuterium-protium separation factor, α, between molecular hydrogen and liquid methylamine in the presence of potassium methylamide catalyst has been measured at low deuterium concentrations over the temperature range -50 to +5 deg C.The separation factor is about 10 percent larger than that for liquid ammonia, and its dependence upon absolute temperature, T, is given by lnα = 0.1135 + (240.05/T) + (43989/T2).The equilibrium constant, K1, for deuterium-protium exchange between hydrogen and the amino group of methylamine vapor has been calculated for all deuterium concentrations at temperatures between 150 and 400 K with partition functions for methylamine derived from an internal rotation-inversion-normal vibration model of methylamine based on spectroscopic data.Conversion of K1 into α values, by inclusion of vapor-liquid fractionation effects, shows that the discrepancy between theory and experiment is less than the combined tolerances (+/- 5 percent) of the two approaches.The dependence of α on deuterium atom fraction is discussed.
