New hydrogen-bond-aided supramolecular synthon: a case study of 2,4,6-trinitroaniline

CrystEngComm ◽  
2013 ◽  
Vol 15 (46) ◽  
pp. 10086 ◽  
Author(s):  
Ivan V. Fedyanin ◽  
Konstantin A. Lyssenko
Keyword(s):  
Hydrogen Bond ◽  
Supramolecular Synthon

When hydrogen bond tailors molecular packing in non-anisometric molecules. The case study of N-alkyl 1,3-diphenyl-4,5-dihydro-1H-pyrazole-5-carboximidamides

2020 ◽  
pp. 1-10
Author(s):  
Sumana Y. Kotian ◽  
Shridevi D ◽  
Srikantamurthy Ningaiah ◽  
Aloir A. Merlo ◽  
André A. Vieira ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Molecular Packing

Hydrogen bonding in enantiomeric versus racemic mono-carboxylic acids; a case study of 2-phenoxypropionic acid

2003 ◽  
Vol 59 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Henning Osholm Sørensen ◽  
Sine Larsen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Carboxylic Acids ◽  
Crystal Packing ◽  
Cyclic Dimer ◽  
Optically Pure ◽  
Pure Enantiomer ◽  
Hydrogen Bonded

The structural and thermodynamic backgrounds for the crystallization behaviour of racemates have been investigated using 2-phenoxypropionic acid (PPA) as an example. The racemate of PPA behaves normally and forms a racemic compound that has a higher melting point and is denser than the enantiomer. Low-temperature crystal structures of the pure enantiomer, the enantiomer cocrystallized with n-alkanes and the racemic acid showed that hydrogen-bonded dimers that form over crystallographic symmetry elements exist in all but the structure of the pure enantiomer. A database search for optically pure chiral mono-carboxylic acids revealed that the hydrogen-bonded cyclic dimer is the most prevalent hydrogen-bond motif in chiral mono-carboxylic acids. The conformation of PPA depends on the hydrogen-bond motif; the antiplanar conformation relative to the ether group is associated with a catemer hydrogen-bonding motif, whereas the more abundant synplanar conformation is found in crystals that contain cyclic dimers. Other intermolecular interactions that involve the substituent of the carboxylic group were identified in the crystals that contain the cyclic dimer. This result shows how important the nature of the substituent is for the crystal packing. The differences in crystal packing have been related to differences in melting enthalpy and entropy between the racemic and enantiomeric acids. In a comparison with the equivalent 2-(4-chlorophenoxy)-propionic acids, the differences between the crystal structures of the chloro and the unsubstituted acid have been identified and related to thermodynamic data.

scholarly journals Untangling Hydrogen Bond Networks with Ion Mobility Spectrometry and Quantum Chemical Calculations: A Case Study on H+XPGG

2019 ◽  
Vol 123 (27) ◽  
pp. 5730-5741
Author(s):  
Daniel Beckett ◽  
Tarick J. El-Baba ◽  
Kevin Gilbert ◽  
David E. Clemmer ◽  
Krishnan Raghavachari
Keyword(s):  
Hydrogen Bond ◽  
Quantum Chemical Calculations ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Quantum Chemical ◽  
Hydrogen Bond Networks

Thermal expansion and dimensionality of a hydrogen bond network: a case study on dimorphic oxalic acid

CrystEngComm ◽  
2020 ◽  
Vol 22 (45) ◽  
pp. 7896-7902
Author(s):  
Suman Bhattacharya
Keyword(s):  
Hydrogen Bond ◽  
Thermal Expansion ◽  
Oxalic Acid ◽  
Intermolecular Interactions ◽  
Crystal Packing ◽  
Hydrogen Bond Network ◽  
Bond Network

Between 156 K–298 K the  oxalic acid polymorphs, α-C2 and β-C2 exhibit comparable volumetric thermal expansions which are correlated to the respective crystal packing and intermolecular interactions in the two forms.

scholarly journals On the Conflicting Estimations of Pigment Site Energies in Photosynthetic Complexes: A Case Study of the CP47 Complex

2016 ◽  
Vol 11 ◽  
pp. ACI.S32151 ◽  
Author(s):  
Tonu Reinot ◽  
Jinhai Chen ◽  
Adam Kell ◽  
Mahboobe Jassas ◽  
Kevin C. Robben ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Population Dynamics ◽  
Photosystem Ii ◽  
Hole Burning ◽  
Protein Subunit ◽  
Structure Population ◽  
Chl A ◽  
Antenna Complex ◽  
Photosynthetic Complexes

We focus on problems with elucidation of site energies ( E n0) for photosynthetic complexes (PSCs) in order to raise some genuine concern regarding the conflicting estimations propagating in the literature. As an example, we provide a stern assessment of the site energies extracted from fits to optical spectra of the widely studied CP47 antenna complex of photosystem II from spinach, though many general comments apply to other PSCs as well. Correct values of E n0 for chlorophyll (Chl) a in CP47 are essential for understanding its excitonic structure, population dynamics, and excitation energy pathway(s). To demonstrate this, we present a case study where simultaneous fits of multiple spectra (absorption, emission, circular dichroism, and nonresonant hole-burned spectra) show that several sets of parameters can fit the spectra very well. Importantly, we show that variable emission maxima (690-695 nm) and sample-dependent bleaching in nonresonant hole-burning spectra reported in literature could be explained, assuming that many previously studied CP47 samples were a mixture of intact and destabilized proteins. It appears that the destabilized subpopulation of CP47 complexes could feature a weakened hydrogen bond between the 13 1 -keto group of Chl29 and the PsbH protein subunit, though other possibilities cannot be entirely excluded, as discussed in this work. Possible implications of our findings are briefly discussed.

Effect of hydrogen bond formation on the elastic molecular scattering: a case study with methanol

2012 ◽  
Vol 110 (5) ◽  
pp. 297-306 ◽  
Author(s):  
Ednilsom Orestes ◽  
Puspitapallab Chaudhuri ◽  
Sylvio Canuto
Keyword(s):  
Hydrogen Bond ◽  
Bond Formation ◽  
Molecular Scattering ◽  
Hydrogen Bond Formation

Conformational analysis of a supramolecular synthon: a case study of 8-hydroxyquinoline

CrystEngComm ◽  
2018 ◽  
Vol 20 (5) ◽  
pp. 652-660 ◽  
Author(s):  
Ivan V. Fedyanin ◽  
Valentina A. Karnoukhova ◽  
Konstantin A. Lyssenko
Keyword(s):  
Conformational Analysis ◽  
Supramolecular Synthon ◽  
Polymorphic Modifications

Conformational analysis of a supramolecular synthon in polymorphic modifications of 8-hydroxyquinoline.

Sign in / Sign up

Export Citation Format

Share Document