@article { ISI:000290127500055, title = {Halogen bonding in 2,5-dichloro-1,4-benzoquinone: insights from experimental and theoretical charge density analysis}, journal = {Crystal Growth \& Design}, volume = {11}, number = {5}, year = {2011}, month = {MAY}, pages = {1855-1862}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Experimental charge density distribution in 2, 5-dichloro-1, 4-benzoquinone has been carried out using high resolution X-ray diffraction data at 90 K to quantitatively evaluate the nature of C-Cl center dot center dot center dot O=C halogen bond in molecular crystals. Additionally, the halogen bond is studied from geometrical point of view and the same has been visualized using Hirshfeld surface analysis. The obtained results from experimental charge density analysis are compared with periodic quantum calculations using B3LYP 6-31G(d,p) level of theory. The topological values at bond critical point, three-dimensional static deformation density features and electrostatic potential isosurfaces unequivocally establish the attractive nature of C-Cl center dot center dot center dot O=C halogen bond in crystalline lattice.

}, issn = {1528-7483}, doi = {10.1021/cg2000415}, author = {Hathwar, Venkatesha R. and Gonnade, Rajesh G. and Munshi, Parthapratim and Bhadbhade, Mohan M. and Row, Tayur N. Guru} } @article {46397, title = {Cocrystals/salts of Furosemide : Interesting case of colour cocrystal polymorphism}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C724}, type = {Meeting Abstract}, keywords = {Color cocrystal polymorphism, Sandwich assembly, Stacking interactions}, issn = {2053-2733}, author = {Sangtani, Ekta and Jha, Kunal and Munshi, Parthapratim and Gonnade, Rajesh} } @article { ISI:000365930300028, title = {Furosemide cocrystals with pyridines: an interesting case of color cocrystal polymorphism}, journal = {Crystal Growth \& Design}, volume = {15}, number = {12}, year = {2015}, month = {DEC}, pages = {5858-5872}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Furosemide (FS), a loop diuretic drug commonly used for the treatment of hypertension and edema, exhibited color cocrystal polymorphism with coformer 4,4{\textquoteright}-bipyridine (4BPY) in the stoichiometry 2:1, albeit both the API and the cocrystal former are colorless. Crystallization from ethanol, isopropanol, ethanol-water (v/v, 1/1) mixture, and acetonitrile yielded pale yellow (form II, thin needles) and orange (form 1II, blocks) cocrystals concomitantly. Needles appeared from solution within a day, while the blocks were obtained after 1-2 days from the same flask, indicating that yellow needles were formed faster and the orange blocks were perhaps formed under thermodynamic conditions. Form 1I cocrystals could also be produced from the variety of common solvents. Cocrystallization of FS with 2,2{\textquoteright}-bipyridine (2BPY) and 4-aminopyridine (4AP) gave colorless cocrystals 2 and 3, respectively, and did not exhibit polymorphism. The single-crystal X-ray structures, powder X-ray diffraction, photophysical characterization, differential scanning calorimetry, hot stage microscopy studies, and density functional theory (DFT) calculations provide insight into the structure property relationship. The common structural features observed in all of the structures is the formation of sandwich motifs comprising FS and pyridines through pi-stacking interactions. These motifs are linked differently through hydrogen bonding interactions in all three directions. The significant color difference between the two cocrystals dimorphs could be attributed to the different pi-stacking patterns and hydrogen bonding interactions between molecules of FS and 4BPY in their cocrystal structures. Investigation on the origin of the color difference using DFT calculations revealed the decrease in HOMO-LUMO gap for form 1II cocrystals (orange) compared to form 1I crystals (light yellow). The crystal-to-crystal thermal transformation of form 1I crystals to form 1II crystals of 1 suggests the role of pi-stacking assemblies in driving the self-assembly.

}, issn = {1528-7483}, doi = {10.1021/acs.cgd.5b01240}, author = {Sangtani, Ekta and Sahu, Sanjay Kumar and Thorat, Shridhar H. and Gawade, Rupesh L. and Jha, Kunal K. and Munshi, Parthapratim and Gonnade, Rajesh G.} } @article { ISI:000363666000023, title = {Highly emissive organic solids with remarkably broad color tunability based on N,C-chelate, four-coordinate organoborons}, journal = {Chemical Communications}, volume = {51}, number = {89}, year = {2015}, month = {SEP}, pages = {16115-16118}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Molecular fluorophores based on N,C-chelate, four-coordinate organo-borons exhibit tunable solid-state emission colors that cover the whole visible region from blue to red. The emission color can be tuned through the substituents on either quinolines or the boron center.

}, issn = {1359-7345}, doi = {10.1039/c5cc06351e}, author = {Shaikh, Aslam C. and Ranade, Dnyanesh S. and Thorat, Shridhar and Maity, Arunava and Kulkarni, Prasad P. and Gonnade, Rajesh G. and Munshi, Parthapratim and Patil, Nitin T.} } @article {43919, title = {Salts and cocrystals of furosemide with pyridines: differences in π-Stacking and color polymorphism}, journal = {Crystal Growth \& Design}, volume = {17}, year = {2017}, month = {JUN}, pages = {3071{\textendash}3087}, type = {Article}, abstract = {

Furosemide (FS), a loop diuretic drug that has a potential to exhibit polymorphism, produced color polymorphs of orange (form 1I) and yellow (form 1II) concomitantly with coformer 1, 2-bis(4-pyridyl)ethylene. However, cocrystallization of FS with other pyridines yielded colorless salts (2 and 4) and cocrystals (3 and 5). The significant color difference between the two polymorphs (forms 1I and 1II) could be attributed to the dissimilar π-stacking patterns between the two components and differences in their highest occupied molecular orbital-lowest unoccupied molecular orbital gap. The molecular packing of form 1I and 2 is very similar, but 2 is colorless due to lack of extended π-conjugation.

}, doi = {10.1021/acs.cgd.6b01868}, author = {Sangtani, Ekta and Mandal, Suman Kumar and Sreelakshmi, A. S. and Munshi, Parthapratim and Gonnade, Rajesh G.} }