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Vol 479, No 1-2 (2018)
- Year: 2018
- Articles: 4
- URL: https://journals.rcsi.science/0012-5016/issue/view/9242
Physical Chemistry
Repeated Elements of the Structure of Liquid Monoethanolamine
Abstract
For the first time, in F-structures of liquid monoethanolamine that were constructed by molecular dynamics simulations at various temperatures, repetition of structural triangles formed by hydrogen-bonded coordinating atoms (O and N) was revealed. A correlation was found between the revealed features of the molecular dynamics structures and the characteristics of monoethanolamine clusters determined by quantum mechanical calculations. It was shown that there are two main types of triangular motifs that ensure strong binding in the system owing to peculiarities of the electron distribution.
47-51
Complexation of TiF4 with PhP(O)[CH2C(O)NMe2]2 in CH2Cl2: Appearance of a Chiral Center at Chelate Coordination
Abstract
The reaction of TiF4 with PhP(O)[CH2C(O)NMe2]2 in CH2Cl2 has been studied by 19F NMR spectroscopy. It has been found that the major reaction products are chelate tetrafluoro complex (η2-L)TiF4 where the ligand is coordinated to the titanium ion through the P=O and C=O groups and cis-TiF4(ОР···L)2 where both ligands are coordinated to the central ion through the more basic P=O groups. Spectral features of the tetrafluoro chelate have been studied, which have been attributed for the first time to the appearance of a chiral center at chelate coordination. The character of manifestation of conformational isomerism of the chelate ring and chiral center in the chelating ligand in mixed octahedral complexes of d0 transition metal fluorides in 19F NMR spectra is discussed.
52-56
Formation of Chiral Structures in UV-Initiated Formose Reaction
Abstract
It has been found that the UV-initiated formose reaction in an extremely concentrated aqueous solution of formaldehyde gives sugars and other biologically significant chiral compounds with sp3-hybridized carbon atom. The reaction leads to an optically active condensed phase, which is a result of the spontaneous spatial separation of enantiomers in the racemate into the antipodes, similarly to the separation of enantiomers of different chirality sign in the famous Pasteur experiments. In our opinion, such a scenario is as close as possible to the actually realized de novo scenario of synthesis of chiral prebiotic molecules and matrices.
57-60
61-65