Intra- and intermolecular hydrogen bonds in ethylene glycol, monoethanolamine, and ethylenediamine

Abstract

The structures of ethylene glycol, aminoethanol, ethylenediamine, and their dimers with the for mation of hydrogen bonds of different types are optimized by density functional theory (DFT) using hybrid functional B3LYP in the basis of 6 31++G(d,p), 6 311++G(2d,2p) and aug CC pVTZ. Energies of interac tions, hydrogen bond parameters, and oscillation frequency are calculated, and NBO analysis is performed. The types of hydrogen bonds formed in dimers of 1,2 disubstituted ethanes X-CH 2 -CH 2 -Y (X, Y = OH, NH 2 ) are established. Keywords: ethylene glycol, aminoethanol, ethylenediamine, intro and intermolecular hydrogen bonds, quan tum chemical methods of calculation.

A Symmetric Recognition Motif between Vicinal Diols: The Fourfold Grip in Ethylene Glycol Dimer

“…Indeed, the question of its preferred dimer structure has been addressed repeatedly by theory, [4][5][6] but not by experimental techniques.B ecause of the torsional flexibility of ethylene glycol, there are several possibilities how the four OH groups of the dimer can engage in hydrogen bonds.None of the previously proposed structures involves more than three hydrogen bonds among these OH groups. [4][5][6][7][8][9][10][11] We present unambiguous combined IR and Raman spectroscopic evidence that ethylene glycol in fact forms an S 4 -symmetric and thus non-polar and achiral dimer with four equivalent hydrogen bonds.U sing Gaussian 09, [12] an extensive search of the intermolecular potential-energy hypersurface at B3LYP-D3(BJ)/6-311 + G(2d,p) level (in short B3LYP) confirms that this structure wins over all triply hydrogen-bonded dimer structures by as ubstantial energy margin.…”

Schwingungsdynamik in O−H···O-verbrückten Aggregaten: FTIR-Spektroskopie vom Nah- bis zum Ferninfraroten

“…103 Andere Studien haben ausgewählte Dimere mit nur einer intermolekularen Wasserstoffbrücke betrachtet. 104,105 Fraglich ist, ob die Suche nach Dimerstrukturen in den Studien mit insgesamt nur drei gefundenen Dimeren 102,103 umfangreich genug war, um die Potentialfläche des Dimers ausreichend abzutasten. In den hier durchgeführten Rechnungen auf B3LYP-D3/6-311+G(2d,p) Niveau konnten allein im Energieintervall von 15 kJ/mol über dem globalen Minimum 14 verschiedene Dimerstrukturen gefunden werden.…”

A Symmetric Recognition Motif between Vicinal Diols: The Fourfold Grip in Ethylene Glycol Dimer

“…Because of the torsional flexibility of ethylene glycol, there are several possibilities how the four OH groups of the dimer can engage in hydrogen bonds. None of the previously proposed structures involves more than three hydrogen bonds among these OH groups …”