TY - JOUR A1 - Parthasarathy, Thiyagaraj A1 - Bhowmik, Aritra A1 - Bhattacharya, Biswajit A1 - Mishra, Manish Kumar A1 - Ghosh, Soumyajit T1 - Reversible twisting-induced crystalline–polycrystalline transformation in cyanoacrylate crystals N2 - Centimeter-long single crystals of cyanoacrylate derivatives exhibit 1D elasticity, 2D plasticity and can be manually twisted and untwisted without any visible fractures, demonstrating exceptional mechanical flexibility and structural resilience. KW - Weak intermolecular interactions KW - Crystals KW - Mechanical flexiblity KW - Micro-focus Raman spectroscopy KW - Single-crystal X-ray diffraction PY - 2025 DO - https://doi.org/10.1039/D5CC05852J SN - 1359-7345 SP - 1 EP - 4 PB - Royal Society of Chemistry (RSC) AN - OPUS4-64962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Parthasarathy, Thiyagaraj A1 - Mishra, Manish Kumar A1 - Bhattacharya, Biswajit A1 - Emmerling, Franziska A1 - Ghosh, Soumyajit T1 - Simultaneously Mechanically Flexible, Photobending, and Acidochromic Cyanostilbene Molecular Crystals N2 - Molecular crystals that respond to multiple stimuli are gaining significant attention for their potential in smart materials like actuators and sensors. However, imparting multiple stimuli-responsive properties to a single crystal remains a major challenge. Herein, we report two cyanostilbene derivative-based crystals 1 and 2, with various responses to stimuli such as mechanical stress, light, acid vapors, etc. Both crystals 1 and 2 demonstrated mechanical flexibility and reversible acidochromism. Additionally, crystal 1 also exhibited light-induced photobending, which is ascribed to Z to E photoisomerization. Detailed structure–property correlation was established to unravel distinct mechanical responses. The development of these multitasking crystals may find applications in multitasking actuators, anticounterfeiting materials, and more. KW - Absorption KW - Crystals KW - Mechanical flexiblity KW - Photoisomerization PY - 2025 DO - https://doi.org/10.1021/acs.cgd.4c01341 VL - 25 IS - 2 SP - 309 EP - 318 PB - American Chemical Society (ACS) AN - OPUS4-62568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nag, Sayak A1 - Bhattacharya, Biswajit A1 - Emmerling, Franziska A1 - Ghosh, Soumyajit T1 - Stress and Light-Induced Dual Mechanical Properties of Two 1,3-Dicyanostilbene Derivative Crystals N2 - Dynamic molecular crystals with multistimuli responses hold immense potential for applications as actuators and smart materials. Here, we report two new 1,3-dicyanostilbene derivative crystals (crystals 1 and 2), which exhibit dual mechanical responses. Both crystals 1 and 2 demonstrate stress-induced mechanical flexibility and light-induced photomechanical bending upon exposure to a 375 nm UV LED. These two distinct mechanical responses are associated with different underlying phenomena and are independent of each other. Mechanical flexibility is attributed to the absence of slip planes and a criss-cross packing arrangement in an isotropic structure, while photomechanical bending is ascribed to the formation of a heterogeneous phase distribution due to Z → E photoisomerization. However, they show thermal reversibility, pointing toward a reversible E → Z back isomerization. This study demonstrates that single molecular crystals combining mechanical flexibility and photomechanical bending can be designed and fabricated for developing multistimuli responsive actuators. KW - Photoisomerization KW - Crystal structure KW - Crystals KW - Flexibility KW - Molecules PY - 2025 DO - https://doi.org/10.1021/acs.cgd.5c00097 SN - 1528-7483 SP - 1 EP - 11 PB - American Chemical Society (ACS) AN - OPUS4-63267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manoharan, Deepak A1 - Ahmad, Shamim A1 - Tothadi, Srinu A1 - Emmerling, Franziska A1 - Bhattacharya, Biswajit A1 - Ghosh, Soumyajit T1 - Linker size dependent mechanical properties of di-imine based molecular crystals N2 - We have demonstrated the ability to modify the mechanical flexibility of molecular crystals by modulating the length of intervening linker moieties while keeping the terminal shape synthons the same. KW - Mechanically flexible molecular crystals KW - Mechanical properties KW - Crystal Engineering PY - 2023 DO - https://doi.org/10.1039/D3CE00928A SN - 1466-8033 SP - 1 EP - 8 PB - RSC CY - London AN - OPUS4-58836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manoharan, Deepak A1 - Ranjan, Subham A1 - Emmerling, Franziska A1 - Bhattacharya, Biswajit A1 - Takamizawa, Satoshi A1 - Ghosh, Soumyajit T1 - Elasto-plastic behaviour with reversible thermosalient expansion in acrylonitrile-based organic crystals N2 - Crystalline materials that exhibit reversible mechanical responses upon exposure to external stimuli have garnered significant attention owing to their potential applications in various fields. Herein, we report a crystal of (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(4-bromophenyl)acrylonitrile) (DSBr), which displays simultaneous elasto-plastic behaviour and reversible thermosalient effects. While elasto-plastic behaviour is attributed to underlying packing features, reversible thermosalient expansion is attributed to uniaxial expansion mediated by heat. Exceptional length increase and contraction upon cooling is due to the restorative nature of weak interactions through a cooperative effect. The cooperative movement of molecules is reflected in the unidirectional expansion of the habit plane. Thermosalient reversible expansion–contraction in elasto-plastic crystals have not been discussed in the literature so far. Detailed analysis reported herein provides a comprehensive understanding of the underlying mechanism of flexibility and thermosalient responses. This crystal's unique blend of reversible thermal expansion with flexibility holds substantial promise for applications in flexible thermal actuators. KW - Materials Chemistry KW - General Chemistry PY - 2024 DO - https://doi.org/10.1039/D3TC04272C SN - 2050-7526 SP - 1 EP - 11 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Parthasarathy, Thiyagaraj A1 - Bhattacharya, Biswajit A1 - Emmerling, Franziska A1 - Ghosh, Soumyajit T1 - Design of mechanically flexible photoresponsive cyanostilbene molecular crystals N2 - Photoresponsive molecular crystals have sparked interest owing to their potential application prospects. In this study, we achieved dual mechanical responses of a cyanostilbene-based crystal BN. The crystal exhibited both stress-induced mechanical flexibility and light-induced photomechanical bending. Two distinct mechanical responses are related to different underlying phenomena and were not interlinked. While elasticity is attributed to criss-cross packing arrangement in the isotropic structure, photomechanical bending is attributed to the formation of heterogeneous phase distribution due to monomer to dimer cycloaddition product formation. The crystal did not demonstrate photoswitching activity. However, it exhibited thermal reversibility, highlighting reversible dimer to monomer conversion. KW - Flexible KW - Molecular crystals PY - 2024 DO - https://doi.org/10.1039/D4CE00571F VL - 26 SP - 4634 EP - 4642 PB - Royal Society of Chemistry (RSC) AN - OPUS4-60888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -