18639-79-7Relevant academic research and scientific papers
Unconventional Ionic Hydrogen Bonds. 2. NH(1+)...? Complexes of Onium Ions with Olefins and Benzene Derivatives
Deakyne, Carol A.,Meot-Ner (Mautner), Michael
, p. 474 - 479 (1985)
Unconventional strong ionic hydrogen bonds of the -XH(1+)...? type, where the electron donor is a ?-bond or an aromatic ?-system, are formed in the clustering reactions of NH4(1+) and MeNH3(1+) with C2H4 and benzene derivatives.The interaction energies range from 10 to 22 kcal mol-1.The experimental results and ab initio calculations on C2H4*NH4(1+), C6H6*NH4(1+), and C6H5F*NH4(1+) indicate that the interaction is primarily electrostatic in nature with little ?-donation into the bond.The most stable structure of C2H4*NH4(1+) is the conformer where one N-H(1+) bond points at the center of the double bond.For C6H6*NH4(1+) and C6H5F*NH4(1+), the lowest energy ?-dimers have two NH4(1+) hydrogens directed towards the ring.The F...H-NH3(1+) ?-complex was studied also for C6H5F*NH4(1+).The latter complex is the more stable of the two at this level of calculation.
Proton Affinities and Photoelectron Spectra of Three-Membered-Ring Heterocycles
Aue, Donald H.,Webb, Hugh M.,Davidson, William R.,Vidal, Mariano,Bowers, Michael T.,at al.
, p. 5151 - 5157 (2007/10/02)
Proton affinities and photoelectron spectra have been measured for azirane, phosphorane, oxirane, and thiirane and for the corresponding dimethylamine, phosphine, ether, and sulphide.The photoelectron spectra have been fully assigned by the use of ab initio STO-431G calculations and structural correlations within these series of molecules.The lone-pair ionization potentials of the heterocycles are higher than those of their open-chain dimethyl analogues because of charge redistribution effects in the C-X bonds and increased lone-pair's character in azirane and phosphirane.The proton affinities are lower in the heterocycles than in their dimethyl analogues as a result of increases in lone-pair's character and, especially for phosphirane, an increase in the RXR angle strain on protonation.Ab initio calculations on the protonated heterocycles and XHn models are presented to help interpret the proton-affinity data.
