Showing papers by "T. N. Guru Row published in 2014"
TL;DR: X-ray charge density analysis provides experimental evidence for this hitherto unexplored 'carbon bonding' interaction and unravels its nature and strength.
148 citations
TL;DR: The experimental evidence for the polarization of the electron density on the fluorine atom of the trifluoromethyl group in the crystal results in the formation of an electron deficient region as discussed by the authors.
Abstract: The experimental evidence for the polarization of the electron density on the fluorine atom of the trifluoromethyl group in the crystal results in the formation of an electron deficient region. This facilitates F···F halogen bond formation along with the subsequent presence of “short” C–H···F intermolecular contacts (rare geometry) which are a significant electronic and structural feature. This study proves that such an interaction has a substantial “electrostatic contribution”. It breaks the long-accepted lore that “organic fluorine is not polarizable”.
59 citations
TL;DR: In this paper, a novel thiophene derivative 7,9-di(thiophen-2-yl)-8H-cyclopenta[a]acenaphthylen-8-one (DTCPA) is shown to exhibit high electrical conductivity (1.97 × 10−2 ± 0.0018 S/cm at RT) in the crystalline state.
Abstract: A novel thiophene derivative 7,9-di(thiophen-2-yl)-8H-cyclopenta[a]acenaphthylen-8-one (DTCPA) is shown to exhibit high electrical conductivity (1.97 × 10–2 ± 0.0018 S/cm at RT) in the crystalline state. The material shows two orders of increase in conductivity from normal solid to single crystalline state. The crystal structure has S···S chalcogen bonding, C–H···O hydrogen bonding, and π···π stacking as the major intermolecular interactions. The nature and strength of the S···S interactions in this structure have been evaluated by theoretical charge density analysis, and its contribution to the crystal packing quantified by Hirshfeld surface analysis. Further, thermal and morphological characterizations have been carried out, and the second harmonic generation (SHG) efficiency has been measured using the Kurtz–Perry method.
58 citations
TL;DR: In this paper, it was shown that gallic acid exhibits a single crystal-to-single crystal transformation upon dehydration, resulting in a difference of three orders of magnitude in proton conduction.
Abstract: Hydrated cocrystal of gallic acid–isoniazid displays a single crystal-to-single crystal transformation upon dehydration, resulting in a difference of three orders of magnitude in proton conduction. The conduction pathway is shown to follow the Grotthus mechanism, supported by theoretical (DFT) calculations.
37 citations
TL;DR: Electrostatic potentials mapped on the isodensity surface show that electron withdrawing substituents turn both C and O atoms of the carbonyl group more electropositive while retaining the direction of polarity.
Abstract: A systematic study of six tetracyclones has been carried out using experimental and theoretical charge density analysis. A three pronged approach based on quantum theory of atoms in molecules (QTAIM), nucleus independent chemical shifts (NICS) criterion, and source function (SF) contributions has been performed to establish the degree of antiaromaticity of the central five-membered ring in all the derivatives. Electrostatic potentials mapped on the isodensity surface show that electron withdrawing substituents turn both C and O atoms of the carbonyl group more electropositive while retaining the direction of polarity.
25 citations
TL;DR: In this paper, the crystal and molecular structures of the potential antidepressant drug fenobam and its derivatives are examined in terms of the preferred form among the two possible tautomeric structures.
Abstract: The crystal and molecular structures of the potential antidepressant drug fenobam and its derivatives are examined in terms of the preferred form among the two possible tautomeric structures. In this study, chemical derivatization has been utilized as a means to “experimentally simulate” the tautomeric preference and conformational variability in fenobam. Eight new derivatives of fenobam have been synthesized, and structural features have been characterized by single-crystal X-ray diffraction and NMR spectroscopy. The specific tautomeric preference found in all of these compounds and their known crystal forms have been construed in terms of the stabilizing intramolecular N–H···O and N–H···S hydrogen bonding. The hierarchy of intramolecular hydrogen bonds evidenced as the preference of the C–H···O hydrogen bond over C–H···N and that of the C–H···N hydrogen bond over C–H···S explains the two distinct conformations adopted by fenobam and thiofenobam derivatives. The relative energy values of different molecu...
17 citations
TL;DR: Density functional theory methods were used to support the proposed mechanism of formation of the products and the structures of the new compounds were confirmed using a battery of techniques, including HRMS (ESI-QTOF) and 2D NMR as well as X-ray crystallography for compound IV.
Abstract: Reinvestigation of the thermolysis of azido-meta-hemipinate (I) yielded, in addition to known II, unusual products III and IV. These products are formed via a rare intramolecular nitrene insertion ...
9 citations