@article { ISI:000228412500017, title = {Structural rationalisation of co-crystals formed between trithiocyanuric acid and molecules containing hydrogen bonding functionality}, journal = {Chemistry - A European Journal}, volume = {11}, number = {8}, year = {2005}, note = {Symposium on Chemistry-A European Conference - Stimulating Concepts in Chemistry, Inst Sci Ingenierie Supramoleculaires, Strasbourg, FRANCE, APR 15, 2005}, month = {APR}, pages = {2433-2439}, publisher = {WILEY-BLACKWELL}, type = {Article}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

Crystallisation of trithiocyanuric acid (TTCA) from various organic solvents that have hydrogen bonding capability (acetone, 2-butanone, dimethylformamide, dimethyl sulfoxide, methanol and acetonitrile) leads to the formation of co-crystals in which the solvent molecules are incorporated together with TTCA in the crystal structure. Structure determination by single-crystal X-ray diffraction reveals that these co-crystals can be classified into different groups depending upon the topological arrangement of the TTCA molecules in the crystal structure. Thus, three different types of single-tape arrangements of TTCA molecules and one type of double-tape arrangement of TTCA molecules are identified. In all co-crystals, hydrogen-bonding interactions are formed through the involvement of N-H bonds of TTCA molecules in these tapes and the other molecule in the co-crystal. Detailed rationalisation of the structural properties of these co-crystals is presented.

}, keywords = {crystal engineering, hydrogen bonds, nitrogen heterocycles, structure elucidation}, issn = {0947-6539}, doi = {10.1002/chem.200400340}, author = {Ahn, Sung-Hoon and PrakashaReddy, J. and Kariuki, B. M. and Chatterjee, S. and Ranganathan, A. and Pedireddi, V. R. and Rao, C. N. R. and Harris, Kenneth D. M.} } @article { ISI:000236960600013, title = {Contrasting solid-state structures of trithiocyanuric acid and cyanuric acid}, journal = {Crystal Growth \& Design}, volume = {6}, number = {4}, year = {2006}, month = {APR}, pages = {846-848}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Although trithiocyanuric acid (TTCA) has been investigated widely as an agent in the formation of molecular cocrystals, the crystal structure of pure TTCA has never been determined. Attempts to grow crystals of pure TTCA by crystallization from solution invariably lead to the formation of solvate cocrystals, and desolvation of these materials leads to polycrystalline powder samples. In this paper, we report the structure determination of pure TTCA directly from powder X-ray diffraction data, using the direct-space genetic algorithm technique for structure solution followed by Rietveld refinement. The structure presents interesting contrasts to that of the oxygen analogue, cyanuric acid, and alludes to the possibility that both compounds might be capable of exhibiting polymorphism.

}, issn = {1528-7483}, doi = {10.1021/cg0601094}, author = {Guo, F. and Cheung, E. Y. and Harris, Kenneth D. M. and Pedireddi, V. R.} } @article { ISI:000340469800024, title = {Highly efficient chiral resolution of DL-arginine by cocrystal formation followed by recrystallization under preferential-enrichment conditions}, journal = {Chemistry-A European Journal}, volume = {20}, number = {33}, year = {2014}, month = {AUG}, pages = {10343-10350}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

An excellent chiral symmetry-breaking spontaneous enantiomeric resolution phenomenon, denoted preferential enrichment, was observed on recrystallization of the 1:1 cocrystal of dl-arginine and fumaric acid, which is classified as a racemic compound crystal with a high eutectic ee value (\>95\%), under non-equilibrium crystallization conditions. On the basis of temperature-controlled video microscopy and in situ time-resolved solid-state (CNMR)-C-13 spectroscopic studies on the crystallization process, a new mechanism of phase transition that can induce preferential enrichment is proposed.

}, keywords = {Amino acids, chiral resolution, cocrystals, Crystal growth, phase transitions}, issn = {0947-6539}, doi = {10.1002/chem.201402446}, author = {Iwama, Sekai and Kuyama, Kazunori and Mori, Yuko and Manoj, Kochunnoonny and Gonnade, Rajesh G. and Suzuki, Katsuaki and Hughes, Colan E. and Williams, P. Andrew and Harris, Kenneth D. M. and Veesler, Stephane and Takahashi, Hiroki and Tsue, Hirohito and Tamura, Rui} } @article { ISI:000352246100007, title = {Exploiting powder x-ray diffraction to establish the solvent-assisted solid-state supramolecular assembly of pillar[5]quinone}, journal = {Crystal Growth \& Design}, volume = {15}, number = {4}, year = {2015}, month = {APR}, pages = {1583-1587}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We report the solvent-mediated supramolecular assembly of pillar[5]quinone (P[5]Q), a symmetric cyclamer containing five benzoquinone moieties bridged by five alternating methylene units. The supramolecular assembly of P[5]Q is shown to be facilitated by 1,1,2,2-tetrachloroethane (TCE) as solvent, producing a microcrystalline solvate material P[5]Q(.)2TCE with a fluffy texture. Optical and electron microscopy reveal that this material has a rod-shaped morphology, extending to several micrometers in length. Due to the microcrystalline nature of the material, structure determination was carried out directly from powder X-ray diffraction data, augmented by high-resolution solid-state C-13 NMR. The two crystallographically distinct TCE molecules occupy different types of void in the structure and have different dynamic properties. Crystallization of P[5]Q was attempted from a large number of different solvents, but only TCE was found to facilitate the formation of a crystalline phase. Indeed, features of the crystal structure suggest that the TCE component plays an important role in promoting the columnar assembly of P[5]Q molecules.

}, issn = {1528-7483}, doi = {10.1021/acs.cgd.5b00277}, author = {Shivakumar, Kilingaru I. and Yan, Yuncheng and Hughes, Colan E. and Apperley, David C. and Harris, Kenneth D. M. and Sanjayan, Gangadhar J.} }