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Updated: Jun 20, 2025

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework
Published on: April 9, 2018
The pattern of bifurcated hydrogen bonds in thiourea cocrystals with diazine derivatives: experimental and quantum
Kinga Wzgarda-Raj1, Adrian Olszewski2, Marcin Palusiak1
1University of Lodz, Faculty of Chemistry, Department of Physical Chemistry, Pomorska 163/165, 90-236 Lodz, Poland.
Abstract:
Cocrystals of thiourea with pyrazine N-oxide as thiourea-pyrazine N-oxide (2/1), C4H4N2O·2CH4N2S, (I), and with phenazine as thiourea-phenazine (6/7), 7C12H8N2·6CH4N2S, (II), both crystallize in the monoclinic space group P21/c. In the crystalline state, molecules of both components are linked by N-H...N hydrogen bonds. In addition, there are R22(8) hydrogen-bond synthons between thiourea molecules in both crystal structures. Furthermore, bifurcated hydrogen bonds between the -NH groups in the thiourea molecule and the N and O atoms in the N-oxide ring [in (I)], as well as the N atom in the central phenazine ring [in (II)], play a significant role in both structures. This emerging motif was thoroughly examined using quantum chemistry methods.
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The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the...

