@article {47345, title = {Significance of secondary forces toward improving the charge carrier mobility of Isoindigo based conjugated small molecules}, journal = {Chemical Physics Letters}, volume = {774}, year = {2021}, month = {JUL}, pages = {138621}, type = {Article}, abstract = {

The charge carrier mobility of conjugated small molecules (CSMs) depends on the intermolecular interactions and morphology. Herein, we report the synthesis of CSMs having different side chains. Hydrogen bonding, lipophilic imbalance and van der Waals interactions are imparted through the asymmetric substitution of Isoindigo. The secondary forces impact thin film morphology, and charge carrier mobility. The CSMs having van der Waals interaction further shows higher charge carrier mobility as a function of improved morphology, and increased temperature. The highest mobility of 0.15 cm2/Vs has been achieved for CSMs with van der Waals interaction.

}, keywords = {Conjugated small molecules, Isoindigo, mobility, OFET, Secondary force}, issn = {0009-2614}, doi = {10.1016/j.cplett.2021.138621}, author = {Dharmapurikar, Satej S. and Kashmir, Arulraj Arul and Kumari, Tanya and Kalalawe, Virbhadra and Kanetkar, Maruti and Chini, Mrinmoy Kumar} } @article {48083, title = {Efficient route to 3,3 {\textquoteleft}-biindolinylidene-diones by iron-catalyzed dimerization of isatins}, journal = {Chemistry-an Asian Journal}, volume = {17}, year = {2022}, month = {AUG}, pages = {e202200414}, type = {Article}, abstract = {

Iron-catalyzed dimerization of various isatin derivatives is described for the efficient synthesis of 3,3 {\textquoteleft}-biindolinylidene-diones (isoindigos). The reaction provides easy access to self-coupled and cross-coupled 3,3 {\textquoteleft}-indolinylidene-diones that have high relevance to biology and materials. This Fe(0)- or Fe(II)-catalyzed dimerization reaction tolerates a wide range of functionalities, such as fluoro, chloro, bromo, alkenyl, nitrile, ether, ester, pyrrolyl, indolyl and carbazolyl groups, including cyclic and acyclic alkyls as well as an alkyl-bearing fatty-alcohol moiety. Especially, the coupling between two distinct isatins provided excellent selectivity for the cross-dimerization with trace of self-couplings. The single-crystal X-ray diffraction study established the molecular structure of eight dimerized products. A preliminary mechanistic study of the Fe-catalyzed dimerization supported the radical pathway for the reaction.

}, keywords = {Cross-coupling, dimerization, iron, Isatin, Isoindigo, Mechanism}, issn = {1861-4728}, doi = {10.1002/asia.202200414}, author = {Jagtap, Rahul A. and Pradhan, Chandini and Gonnade, Rajesh G. and Punji, Benudhar} } @article {48742, title = {i-Indigo-based self-assembled microparticles and their conversion to nanoparticles}, journal = {ChemistrySelect}, volume = {8}, year = {2023}, month = {AUG }, pages = {e202300859}, type = {Article}, abstract = {

Microscopic particles (MPs) are used to scatter and reflect UV light. It is well established that inorganic MPs such as TiO2 and ZnO produce carcinogens. Therefore, organic MPs are explored for UV absorption. Conjugated chromophores with differing lipophilicity usually self-assemble into nanoscopic structures. In our previous experiments, unsymmetrical i-Indigo was found to self-assemble into 500 nm particles. We hypothesized that the size of the self-assembled particles can be increased by increasing the lipophilicity difference between the side chains. Toward this objective, we have chosen the i-Indigo core with TEG and alkyl chains as side chains. As a result, the i-Indigo molecules were found to self-assemble into 3 \& mu; spheres in solution. By substituting side chains with different lipophilicity, i-Indigo microparticles with the size of 5 \& mu; are prepared. A careful analysis showed that the spheres are similar to a soccer ball, and they deflate upon drying on the substrate surface. The judiciously chosen side chain binds with a metal-ion (Cs+) and forms nanoscopic assemblies. After Cs+ binding, the size of the particles is decreased drastically to 100 nm. The simple addition of ions converts microscopic assemblies into nanoscopic assemblies.

}, keywords = {Isoindigo, microparticles, Nanoparticles, Self-assembly, UV absorber}, issn = {2365-6549}, doi = {10.1002/slct.202300859}, author = {Singh, Anup Kumar and Swain, Gitanjali} }