@article { ISI:000324316300042, title = {Identification of molecular crystals capable of undergoing an acyl-transfer reaction based on intermolecular interactions in the crystal lattice}, journal = {Chemistry-A European Journal}, volume = {19}, number = {38}, year = {2013}, month = {SEP}, pages = {12867-12874}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Investigation of the intermolecular acyl-transfer reactivity in molecular crystals of myo-inositol orthoester derivatives and its correlation with crystal structures enabled us to identify the essential parameters to support efficient acyl-transfer reactions in crystals: 1)the favorable geometry of the nucleophile (OH) and the electrophile (CO) and 2)the molecular assembly, reinforced by CH interactions, which supports a domino-type reaction in crystals. These parameters were used to identify another reactive crystal through a data-mining study of the Cambridge Structural Database. A 2:1 co-crystal of 2,3-naphthalene diol and its di-p-methylbenzoate was selected as a potentially reactive crystal and its reactivity was tested by heating the co-crystals in the presence of solid sodium carbonate. A facile intermolecular p-toluoyl group transfer was observed as predicted. The successful identification of reactive crystals opens up a new method for the detection of molecular crystals capable of exhibiting acyl-transfer reactivity.

}, keywords = {Acylation, domino reactions, intermolecular interactions, solid-state reactions, X-ray diffraction}, issn = {0947-6539}, doi = {10.1002/chem.201301058}, author = {Tamboli, Majid I. and Krishnaswamy, Shobhana and Gonnade, Rajesh G. and Shashidhar, Mysore S.} } @article {46384, title = {Acyl-transfer reactions in molecular crystals: reactivity correlation with crystal structure}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {APR}, pages = {C771}, type = {Meeting Abstract}, keywords = {crystal engineering, intermolecular interactions, solid-state reactions}, issn = {2053-2733}, author = {Gonnade, Rajesh G. and Shashidhar, Mysore S.} } @article {46399, title = {Additive induced capture of elusive polymorphs of conformationally flexible Sulfonamides/Sulfoesters}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C776}, type = {Meeting Abstract}, keywords = {additive induced polymorphism, intermolecular interactions, phase transition}, issn = {2053-2733}, author = {Shaikh, Samir Rashid and Gawade, Rupesh L. and Chakravarty, Debamitra K. and Puranik, Vedavati G. and Gonnade, Rajesh} } @article { ISI:000356520400003, title = {Computational strategies for understanding the nature of interaction in dioxin imprinted nanoporous trappers}, journal = {Journal of Molecular Recognition}, volume = {28}, number = {7}, year = {2015}, month = {JUL}, pages = {427-437}, publisher = {WILEY-BLACKWELL}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

A new computational model capable of understanding the nature of interactions in signature complexes formed between the template(2,3,7,8-tetrachlorodibenzo-p dioxin (TCDD)) and the functional monomers (methacrylic acid (MAA)) using density functional theory (DFT) has been designed. The polymer precursors were optimized for geometries in polymerization media, computing the interaction energies between template molecules and functional monomers of transient pre-polymerized complexes (PPC), and structural and vibrational properties reference to theoretical infrared spectra were computed using DFT of B3LYP/6 311+G(d,p) hybrid functional method. Atom in molecule theory was used to analyze the hydrogen-bonding characteristics of PPC of MAA-TCDD. Considering the theoretical titrations conducted in a virtual solvent box, it was found that the 1:4 molar ratio was required to form the most stable PPC in a given solvent system. The electron density plots indicate strong hydrogen bonding as shown by the 2pz dominant highest occupied molecular orbital (HOMO) character that could be the preferable sites of binding for target molecule, TCDD. Considering HOMO approach, the active adsorption sites in molecularly imprinted polymer was modeled to get insight on molecular recognition property for targeted molecule, TCDD. The proposed computational protocol is simple, accurate, and novel to design the polymer and is useful to predict the properties of polymer systems than the conventional theoretical analysis of template-monomer interactions. Copyright (c) 2015 John Wiley \& Sons, Ltd.

}, keywords = {carcinogenic pollutants, computer simulations, Density Functional Theory (DFT), intermolecular interactions, Molecularly Imprinted Polymers (MIP)}, issn = {0952-3499}, doi = {10.1002/jmr.2459}, author = {Khan, Muntazir S. and Pal, Sourav and Krupadam, Reddithota J.} } @article {45740, title = {Mechanochemical synthesis of N-salicylideneaniline: thermosalient effect of polymorphic crystals}, journal = {IUCRJ}, volume = {4}, year = {2017}, month = {MAY}, pages = {243-250}, type = {Article}, abstract = {

Polymorphs of the dichloro derivative of N-salicylideneaniline exhibit mechanical responses such as jumping (Forms I and III) and exploding (Form II) in its three polymorphs. The molecules are connected via the amide N-H center dot center dot center dot O dimer synthon and C-Cl center dot center dot center dot O halogen bond in the three crystal structures. A fourth high-temperature Form IV was confirmed by variable-temperature single-crystal X-ray diffraction at 180 degrees C. The behaviour of jumping exhibited by the polymorphic crystals of Forms I and III is due to the layered sheet morphology and the transmission of thermal stress in a single direction, compared with the corrugated sheet structure of Form II such that heat dissipation is more isotropic causing blasting. The role of weak C-Cl center dot center dot center dot O interactions in the thermal response of molecular crystals is discussed.

}, keywords = {crystal design, crystal engineering, Halogen bonding, hydrogen bonding, intermolecular interactions, materials science, mechanochemistry, polymorphism}, issn = {2052-2525}, doi = {10.1107/S2052252517004043}, author = {Mittapalli, Sudhir and Perumalla, D. Sravanakumar and Nangia, Ashwini} } @article {43817, title = {Nature of selenium hydrogen bonding: gas phase spectroscopy and quantum chemistry calculations}, journal = {Physical chemistry Chemical physics}, volume = {19}, year = {2017}, month = {SEP}, pages = {24179-24187}, type = {Article}, abstract = {

Subsequent to the recent re-definition of hydrogen bonding by the IUPAC committee, there has been a growing search for finding the presence of this ever interesting non-covalent interaction between a hydrogen atom in an X-H group and any other atom in the periodic table. In recent gas phase experiments, it has been observed that hydrogen bonding interactions involving S and Se are of similar strength to those with an O atom. However, there is no clear explanation for the unusual strength of this interaction in the case of hydrogen bond acceptors which are not conventional electronegative atoms. In this work, we have explored the nature of Se hydrogen bonding by studying indole...dimethyl selenide (indmse) and phenol...dimethyl selenide (phdmse) complexes using gas phase IR spectroscopy and quantum chemistry calculations. We have found through various energy decomposition analysis (EDA) methods and natural bond orbital (NBO) calculations that, along with electrostatics and polarization, charge transfer interactions are important to understand Se/S hydrogen bonding and there is a delicate balance between the various interactions that plays the crucial role rather than a single component of the interaction energy. An in-depth understanding of this type of non-covalent interaction has immense significance in biology as amino acids containing S and Se are widely present in proteins and hence hydrogen bonding interactions involving S and Se atoms contribute to the folding of proteins.

}, keywords = {Center-Dot-O, Clusters, Co-Ordination, Complexes, intermolecular interactions, Proteins, Replacement, spectra, Strength, Sulfur}, issn = {1463-9076}, doi = {10.1039/c7cp05265k}, author = {Mishra, Kamal K. and Singh, Santosh K. and Ghosh, Paulami and Ghosh, Debashree and Das, Aloke} } @article {47159, title = {Experimental and theoretical charge density, intermolecular interactions and electrostatic properties of metronidazole}, journal = {Acta Crystallographica Section B-Structural Science Crystal Engineering and Materials}, volume = {75}, year = {2019}, month = {DEC}, pages = {942-953}, type = {Article}, abstract = {

Metronidazole is a radiosensitizer; it crystallizes in the monoclinic system with space group P2(1)/c. The crystal structure of metronidazole has been determined from high-resolution X-ray diffraction measurements at 90 K with a resolution of (sin 0/lambda) max = 1.12 angstrom(-1). To understand the charge-density distribution and the electrostatic properties of metronidazole, a multipole model refinement was carried out using the Hansen-Coppens multipole formalism. The topological analysis of the electron density of metronidazole was performed using Bader{\textquoteright}s quantum theory of atoms in molecules to determine the electron density and the Laplacian of the electron density at the bond critical point of the molecule. The experimental results have been compared with the corresponding periodic theoretical calculation performed at the B3LYP/6-31G** level using CRYSTAL09. The topological analysis reveals that the N-O and C-NO2 exhibit less electron density as well as negative Laplacian of electron density. The molecular packing of crystal is stabilized by weak and strong inter- and intramolecular hydrogen bonding and H center dot center dot center dot H interactions. The topological analysis of O-H center dot center dot center dot N, C-H center dot center dot center dot O and H center dot center dot center dot H intra- and intermolecular interactions was also carried out. The electrostatic potential of metronidazole, calculated from the experiment, predicts the possible electrophilic and nucleophilic sites of the molecule; notably, the hydroxyl and the nitro groups exhibit large electronegative regions. The results have been compared with the corresponding theoretical results.

}, keywords = {atomic valence index, Electron density, Electrostatic potential, intermolecular interactions, metronidazole, radiosensitizer}, doi = {10.1107/S2052520619011272}, author = {Kalaiarasi, Chinnasamy and George, Christy and Gonnade, Rajesh G. and Hathwar, Venkatesha R. and Poomani, Kumaradhas} } @article {46640, title = {Investigation of bond topological and electrostatic properties of plumbagin molecule: an experimental and theoretical charge density study}, journal = {Journal of Molecular Structure}, volume = {1220}, year = {2020}, month = {NOV}, pages = {128714}, type = {Article}, abstract = {

Plumbagin is a naturally occurring derivative with several medicinal properties including antioxidants, antifungal, antimalarial, leprosy and antitumor properties; their structural and electrostatic properties are yet to be determined. The crystal structure of plumbagin has been solved; it shows that the compound crystallizes in P2(1)/c space group with two molecules in the asymmetric unit. The electron density distribution of both molecules have determined from multipole model refinement. Among all the C-O bonds of both molecules (I \& II), the OH group connected C-O bond and the methyl group connected C-C bond exhibits less electron density and the negative Laplacian of electron density as well. Further, the electrostatic potential (ESP) surface of two plumbagin molecules show some difference in their electronegative regions. The carbonyl O-atoms exhibit high electronegative ESP regions which are the key reactive locations of plumbagin when bind with the active site of target protein and in the ESP map, an aromatic pi-cloud also observed in one of the molecule. The electron density distribution of O-H center dot center dot center dot O intermolecular interactions between the molecules I and II, reveals that these interactions are found very stronger than the other interactions in the crystal. (C) 2020 Elsevier B.V. All rights reserved.

}, keywords = {Dipole moment, Electron density, Electrostatic potential, intermolecular interactions, Plumbagin}, issn = {0022-2860}, doi = {10.1016/j.molstruc.2020.128714}, author = {Kalaiarasi, Chinnasamy and Sivanandam, Magudeeswaran and Suganya, Suresh and Christy, George and Gonnade, Rajesh G. and Hathwar, Venkatesha R. and Kumaradhas, Poomani} } @article {47631, title = {Construction of two-component chemically reactive supramolecular assemblies-acyl migration reactions in cocrystals of napthalene-2,3-diol and its diesters}, journal = {ChemPlusChem}, volume = {86}, year = {2021}, month = {AUG}, pages = {1128-1134}, type = {Article}, abstract = {Reactions in solids are of contemporary interest due to applications in pharmaceutical industries to environmental sustainability. Although several reactive crystals that support chemical reactions have been identified and characterized, the same cannot be said about reactive cocrystals. Earlier we correlated the facile acyl group transfer reactions in crystals with supramolecular parameters obtained from the crystal structures. The structure-reactivity correlation revealed the requirement of proper juxtaposition of electrophile (C=O) and the nucleophile (OH) with distance (similar to 3.2 angstrom) and angle (similar to 90 degrees) along the chain structure. The current article describes the preparation of cocrystals that are capable of supporting intermolecular acyl group transfer reactions in a group of structurally similar molecules. The cocrystals of naphthalene 2,3-diol and its corresponding diesters showed a facile solid state acyl transfer reaction, which has been well correlated with their crystal structures.}, keywords = {Acylation, domino reactions, intermolecular interactions, reaction in cocrystal, solid-state reactions, X-ray diffraction}, issn = {2192-6506}, doi = {10.1002/cplu.202100139}, author = {Bahadur, Vir and Gonnade, Rajesh G. and Tamboli, I. Majid and Krishnaswamy, Shobhana and Shashidhar, Mysore S.} }