@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 = {<p>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.</p>},
	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 {44137,
	title = {Thermomechanical effect in molecular crystals: the role of halogen-bonding interactions},
	journal = {IUCRJ},
	volume = {4},
	year = {2017},
	month = {NOV},
	pages = {812-823},
	type = {Article},
	abstract = {The design and synthesis of mechanically responsive materials is interesting because they are potential candidates to convert thermal energy into mechanical work. Reported in this paper are thermosalient effects in a series of halogen derivatives of salinazids. The chloro derivative, with higher electronegativity and a weaker inter-halogen bond strength (Cl center dot center dot center dot Cl) exhibits an excellent thermal response, whereas the response is weaker in the iodo derivative with stronger I center dot center dot center dot I halogen bonding. 3,5-Dichlorosalinazid (Compound-A) exists in three polymorphic forms, two room-temperature polymorphs (Forms I and II) and one high-temperature modification (Form III). The transformation of Form I to Form III upon heating at 328-333 K is a reversible thermosalient transition, whereas the transformation of Form II to Form III is irreversible and nonthermosalient. 3,5-Dibromo- (Compound-B) and 3-bromo-5-chloro(Compound-C) salinazid are both dimorphic: the Form I to Form II transition in Compound-B is irreversible, whereas Compound-C shows a reversible thermosalient effect (362-365 K). In the case of 3,5-diiodosalinazid (CompoundD) and 3,5-difluorosalinazid (Compound-E), no phase transitions or thermal effects were observed. The thermosalient behaviour of these halosalinazid molecular crystals is understood from the anisotropy in the cell parameters (an increase in the a axis and a decrease in the b and c axes upon heating) and the sudden release of accumulated strain during the phase transition. The dihalogen salinazid derivatives (chlorine to iodine) show a decrease in thermal effects with an increase in halogen-bond strength. Interestingly, Compound-B shows solid-state photochromism in its polymorphs along with the thermosalient effect, wherein Form I is cyan and Form II is light orange.},
	doi = {10.1107/S2052252517014658},
	author = {Mittapalli, Sudhir and Perumalla, D. Sravanakumar and Nanubolu, Jagadeesh Babu and Nangia, Ashwini}
}
