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Seminar

Crystals’ Gymnastics: Mechanically Flexible Organic Single Crystals

Wednesday, 22 July 2015, 13:30-15:00
Talk given by Prof. C. Malla Reddy Department of Chemical Sciences Indian Institute of Science Education and Research (IISER) Kolkata, West Bengal, India Abstract: Molecular crystals are generally perceived to be rigid and brittle. Recent studies from several groups, including ours, suggest that certain molecular crystals can display exceptional mechanical flexibility. Self-assembled structures in such crystals can accommodate large amounts of stress by allowing coordinated molecular movements, typically via weak interaction or slip planes. However, studies on mechanical properties of molecular crystals have remained relatively scarce despite their unique applications in optoelectronics, mechanical actuators, pharmaceuticals and explosives.(1) To achieve the high-performance (such as charge transport) in materials it is vital to conserve the orientational order of molecules and bonds in the solid-state, i.e. they need to show excellent mechanical durability, self-healing capabilities and stress dissipating behaviors. In our studies, we showed that both flexibility and crystallinity can be simultaneously achieved in elastically bendable organic single crystals.(2) The structure-property correlation studies reveal that by controlling molecular packing and spatial distribution of noncovalent interactions, the crystal properties, such as mechanical flexibility, mechanochromic luminescence, pharmaceutical tabletability, can be tuned.3 On the other hand, mechanically flexible, compliant (soft) crystals can also be rationally designed by introducing slip planes using the crystal engineering approach.(3,4) 1) (a) Reddy, C. M.; Krishna, G. R.; Ghosh, S. CrystEngComm 2010, 12, 2296. (b) Sahoo, S. C., Sinha, S. B., Kiran, M. S. R. N., Ramamurty, U., Dericioglu, A. F., Reddy, C. M., Naumov, P., J. Am. Chem. Soc., 2013, 135, 13843. (2) Ghosh, S.; Reddy, C. M. Angew. Chem. Int. Ed. 2012, 51, 10319. (3) Krishna, G. R.; Kiran, M. S. R. N.; Fraser, C. L.; Ramamurty, U.; Reddy, C. M.. Adv. Funct. Mater. 2013, 23, 1422. (4) M. K. Panda, S. Ghosh, N. Yasuda, T. Moriwaki, G. D. Mukherjee, C. M. Reddy and P. Naumov, Nature Chem. 2015, 7, 65-72.
This event is part of the eventgroup INT Talks
Speaker
Prof. C. Malla Reddy

Indian Institute of Science Education and Research, Kolkata, India
http://www.iiserkol.ac.in/people/faculty/dcs/cmreddy
Organizer
Dr. Christian Kübel
Institute of Nanotechnology (INT)
Karlsruhe Institute of Technology (KIT)
Eggenstein-Leopoldshafen
Mail: christian kuebel does-not-exist.kit edu
Targetgroup
Interested / Everyone
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