3 research outputs found
Studying the Role of CO···CO, CO···N–O, and N–O···N–O Dipole–Dipole Interactions in the Crystal Packing of 4‑Nitrobenzoic Acid and 3,3′-Dinitrobenzophenone Polymorphs: An Experimental Charge Density Study
An experimental charge density study
of 4-nitrobenzoic acid and
3,3′-dinitrobenzophenone polymorphs has been performed to study
the role played by various intermolecular interactions in the crystal
packing. The study highlights the importance of dipole–dipole
interactions analyzed with the help of Bader’s quantum theory
of atoms in molecules (QTAIM), low-reduced density gradient (RDG)
based topological descriptors of electron density and computations.
The molecular pairs held by antiparallel CO···CO,
CO···N–O, and N–O···N–O
type dipole–dipole interactions were found to contribute significantly
toward stability especially in the case of 3,3′-dinitrobenzophenone,
Form <b>II</b>. The low-RDG based descriptors were used for
understanding the nature of these dipole–dipole interactions,
which indicates the involvement of multiple atoms in stabilizing many
of these interactions. The significant contributions from the O···C,
O···O, and O···N contacts arising from
these dipole–dipole interactions in crystal packing are also
revealed from the Hirshfeld surface analysis of these crystals
Rational Coformer Selection and the Development of New Crystalline Multicomponent Forms of Resveratrol with Enhanced Water Solubility
We
report the development of 10 new cocrystal forms of the nutraceutical
compound resveratrol obtained through a rational coformer screening
by utilizing the interaction site pairing energy differences computed
based on molecular electrostatic potential calculations. A new monohydrate
form of resveratrol and 10 novel cocrystals with 9 different coformers
were characterized in the study. Among the newly developed solid forms
of resveratrol, two of its cocrystals with (1) a Generally Recognized
As Safe compound piperazine and (2) the bioactive compound methenamine
were subjected to aqueous solubility determination. The newly developed
piperazine cocrystal exhibits the highest aqueous solubility among
the previously known cocrystals of resveratrol
Synthesis of Octabromoperylene Dianhydride and Diimides: Evidence of Halogen Bonding and Semiconducting Properties
A facile synthesis of octabromoperylene-3,4,9,10-tetracarboxylic
dianhydride (Br<sub>8</sub>-PDA) (<b>1</b>), its diimides (Br<sub>8</sub>-PDIs) (<b>2a</b>–<b>e</b>), and bis-,
tris-, and tetra-amino substituted diimides (<b>5a</b>–<b>c</b>) with six, five, and four remaining substitutable Br atoms,
respectively, is reported. Octabromination results in facile chemical/electrochemical
reduction, radical anion formation, and red-shifted optical properties.
For the first time, diverse halogen-bonding interactions were identified
in the PDA/PDI, which along with the attractive electronic features
enhance the electron-transport characteristics compared to the di-/tetra-brominated
PDIs (<b>3</b>/<b>4</b>)