01598nas a2200181   4500008004100000245016400041210006900205260000800274300001400282490000700296520086600303100002301169700002701192700002701219700002401246700001801270856012801288       2018                        eng d00aEffect of crystal packing on the thermosalient effect of the pincer-type diester naphthalene-2,3-diyl-bis(4-fluorobenzoate): a new class II thermosalient solid0 aEffect of crystal packing on the thermosalient effect of the pin  cMAR  a4133-41390 v243 aThe pincer-like double ester naphthalene-2,3-diyl-bis(4-fluorobenzoate) (2) is pentamorphic. Upon heating crystals of form I to below their melting point (441-443 K), they undergo a phase transition accompanied by a thermosalient effect, that is, rare and visually striking motility whereby the crystals jump or disintegrate. The phase transition and the thermosalient effect are reversible. Analysis of the crystal structure revealed that form I is a class II thermosalient solid. Crystals of form III also underwent a reversible phase transition in the temperature range of 160 to 170 K; however, they were not thermosalient. Comparison of the structures and the mechanical responses of the two polymorphs revealed that the thermosalient effect of form I was due to reversible closing and opening of the arms of the diester molecules in a tweezer-like action.1 aTamboli, Majid, I.1 aKarothu, Durga, Prasad1 aShashidhar, Mysore, S.1 aGonnade, Rajesh, G.1 aNaumov, Pance  uhttps://library.ncl.res.in/content/effect-crystal-packing-thermosalient-effect-pincer-type-diester-naphthalene-23-diyl-bis401944nas a2200241   4500008004100000022001400041245007900055210006900134260000800203300001400211490000700225520118000232100001801412700001701430700002401447700002201471700002101493700002201514700002001536700001801556700001901574856010901593       2019                        eng d  a1528-748300aCrystalline acylhydrazone photoswitches with multiple mechanical responses0 aCrystalline acylhydrazone photoswitches with multiple mechanical  cMAY  a3039-30440 v193 a<p>The advancement of our understanding of stimuli responsive molecular crystals has led to the realization that they hold great yet unexplored potential as adaptive materials. Although molecular crystals that exhibit a single mechanical response to a single input stimulus are now abundant, crystals that are capable of response to multiple stimuli are rather scarce. Here we report two photoswitchable acylhydrazone derivatives, Ac-1 and Ac-2, which respond to light as well as to mechanical force. Upon application of localized mechanical stress, the anhydrous (Ac-1a) and monohydrate (Ac-1h) crystals of Ac-1 undergo plastic shearing deformation and bending, whereas monohydrate crystals of Ac-2 undergo elastic deformation. When they are exposed to UV light, crystals of Ac-1h and Ac-2 undergo photoinduced bending; on the other hand, crystals of Ac-1a and thicker crystals of Ac-2 exhibit photosalient effect (light-induced leaping). It is demonstrated that the synergistic action of multiple stimuli (UV light and force) elicits enhanced mechanical response, and this strategy could be employed in the future to increase the efficacy of single crystal actuators.</p>
1 aGupta, Poonam1 aPanda, Tamas1 aAllu, Suryanarayana1 aBorah, Silpisikha1 aBaishya, Anamika1 aGunnam, Anilkumar1 aNangia, Ashwini1 aNaumov, Pance1 aNath, Naba, K.  uhttps://library.ncl.res.in/content/crystalline-acylhydrazone-photoswitches-multiple-mechanical-responses