scholarly journals Vapor Pressures of Molecular Crystals. XI. Vapor Pressures of Crystalline Urea and Diformylhydrazine. Energies of Hydrogen Bonds in these Crystals

1956 ◽  
Vol 29 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Keisuke Suzuki ◽  
Shun-ichi Onishi ◽  
Tsutomu Koide ◽  
Sy\={u}z\={o} Seki
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Crystals ◽  
Vapor Pressures ◽  
Crystalline Urea

Associations of squaric acid and its anions as multiform building blocks of hydrogen-bonded molecular crystals

2001 ◽  
Vol 57 (6) ◽  
pp. 859-865 ◽  
Author(s):  
Gastone Gilli ◽  
Valerio Bertolasi ◽  
Paola Gilli ◽  
Valeria Ferretti
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Engineering ◽  
Negative Charge ◽  
Three Dimensional ◽  
Molecular Crystals ◽  
Building Blocks ◽  
Squaric Acid ◽  
Orthosilicic Acid ◽  
Molecular Plane ◽  
Dimensional Crystal

Squaric acid, H2C4O4 (H2SQ), is a completely flat diprotic acid that can crystallize as such, as well as in three different anionic forms, i.e. H2SQ·HSQ−, HSQ− and SQ2−. Its interest for crystal engineering studies arises from three notable factors: (i) its ability of donating and accepting hydrogen bonds strictly confined to the molecular plane; (ii) the remarkable strength of the O—H...O bonds it may form with itself which are either of resonance-assisted (RAHB) or negative-charge-assisted [(−)CAHB] types; (iii) the ease with which it may donate a proton to an aromatic base which, in turn, back-links to the anion by strong low-barrier N—H+...O1/2− charge-assisted hydrogen bonds. Analysis of all the structures so far known shows that, while H2SQ can only crystallize in an extended RAHB-linked planar arrangement and SQ2− tends to behave much as a monomeric dianion, the monoanion HSQ− displays a number of different supramolecular patterns that are classifiable as β-chains, α-chains, α-dimers and α-tetramers. Partial protonation of these motifs leads to H2SQ·HSQ− anions whose supramolecular patterns include ribbons of dimerized β-chains and chains of emiprotonated α-dimers. The topological similarities between the three-dimensional crystal chemistry of orthosilicic acid, H4SiO4, and the two-dimensional one of squaric acid, H2C4O4, are finally stressed.

Theoretical Modeling of the N-H and N-D Stretching Bands of Hydrogen-Bonded 1-Methylthymine Crystal and Its Deuterated Form

2006 ◽  
Vol 2 (4) ◽  
pp. 205-219
Author(s):  
Marek Boczar ◽  
Łukasz Boda ◽  
Marek J. Wójcik
Keyword(s):  
Hydrogen Bonds ◽  
High Frequency ◽  
Molecular Crystals ◽  
Low Frequency ◽  
Unit Cell ◽  
Fermi Resonance ◽  
Bending Vibrations ◽  
Theoretical Simulation ◽  
Stretching Vibrations ◽  
Centrosymmetric Dimers

Theoretical model for vibrational interactions in the hydrogen bonds in molecular crystals with four molecules forming two centrosymmetric dimers in the unit cell is presented. The model takes into account anharmonic-type couplings between the high-frequency N-H(D) and the low-frequency N•••O stretching vibrations in each hydrogen bond, resonance interactions (Davydov coupling) between equivalent hydrogen bonds in each dimer, resonance interdimer interactions within an unit cell and Fermi resonance between the N-H(D) stretching fundamental and the first overtone of the N-H(D) in-plane bending vibrations. The vibrational Hamiltonian, selection rules, and expressions for the integral properties of an absorption spectrum are derived. The model is used for theoretical simulation of the νs stretching bands of 1-methylthymine and its ND derivative at 300 K. The effect of deuteration is successfully reproduced by our model.

scholarly journals Hydrogen bonds in molecular crystals alanine and tyrosine: NBO analysis

2020 ◽  
Vol 64 (10) ◽  
pp. 1-6
Author(s):  
Tatiana G. Volkova ◽  
◽  
Iroda Mamirjon kizi Abdukhalimova ◽  
Irina O. Talanova ◽  
◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Charge Transfer ◽  
Hydrogen Bonds ◽  
Molecular Crystals ◽  
Dft Method ◽  
Nbo Analysis ◽  
Chemical Modeling ◽  
Theoretical Concepts ◽  
Oh Groups ◽  
The Third

At present, the theoretical concepts of the hydrogen bond (H-bond) in condensed media, for example, in living systems, biomolecules, are not fully solved. Quantum chemical modeling is used as one of the methods for studying the nature and determining the strength of the H-bond. In this paper, we continue to study the system of hydrogen bonds in molecular crystals of alanine and tyrosine. The dimers of these amino acids were modeled using the DFT method using the B97D functional with bases 6-31++G**. In the framework of NBO analysis, the stabilization energies of the formed hydrogen bond and the value of the transferred charge are calculated. It is shown that in alanine dimers, the main factor affecting the h-bond stabilization energy is the geometric parameters and, first of all, (N-H...O). The binding σ-orbital of the hydrogen bond is the result of the interaction of a hybrid NBO of the lone electron pairs of an oxygen atom and a loosening σ*-NBO N−H bond. The nature of bond formation in all three cases is the same, and the charge transfer value is greater than the value of the bond criterion, which indicates the presence of hydrogen bonds in all analyzed alanine systems. In tyrosine dimers, two H-bonds are formed that are similar in nature, as well as in geometric and energy parameters. The third H-bond is very weak, and the amount of charge transfer indicates its absence. The main interaction between the molecules in the third tyrosine dimer is the H-bond between the –СОО− and –OH groups. It was found that the scheme of formation of hydrogen bonds in molecular crystals of tyrosine is somewhat different from that of alanine.

scholarly journals Cocrystal trimorphism as a consequence of the orthogonality of halogen- and hydrogen-bonds synthons

2019 ◽  
Vol 55 (93) ◽  
pp. 14066-14069
Author(s):  
Filip Topić ◽  
Katarina Lisac ◽  
Mihails Arhangelskis ◽  
Kari Rissanen ◽  
Dominik Cinčić ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Critical Role ◽  
Molecular Crystals

Trimorphic cocrystals, i.e. multi-component molecular crystals with three polymorphic structures, are exceedingly rare. First example of a trimorphic halogen-bonded cocrystal, reported here, shows a critical role for the interaction orthogonality.

Sulfonamide Molecular Crystals: Structure, Sublimation Thermodynamic Characteristics, Molecular Packing, Hydrogen Bonds Networks

2013 ◽  
Vol 13 (9) ◽  
pp. 4002-4016 ◽  
Author(s):  
German L. Perlovich ◽  
Alex M. Ryzhakov ◽  
Valery V. Tkachev ◽  
Lars Kr. Hansen ◽  
Oleg A. Raevsky
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Crystals ◽  
Thermodynamic Characteristics ◽  
Molecular Packing
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