This Rennes 1 Foundation Prize is attributed for a research work of high scientific quality.
Arun DHAKA joined the Rennes Institute of Chemical Sciences (ISCR) in 2018 following his Integrated BS-MS degree in Chemistry, obtained at the Indian Institute of Science Education and Research (IISER) in Thiruvananthapuram (Kerala, India) under the supervision of Pr. Kana M. Sureshan. While at the ISCR, Arun undertook his thesis within the Condensed Matter and Electroactive Systemes (MaCSE) team, with Ie-Rang Jeon and Marc Fourmigué as thesis directors. Arun’s research is part of the field of crystal engineering, in particular the implementation of so-called sigma-hole interactions in the development of crystals and co-crystals with chemical (topochemical reactions) and physical (electrical) attractive properties. His thesis work, entitled " Halogen & chalcogen bonding in molecular crystals ", was defended in March 2022.
More specifically, the PhD work focused on the implementation of halogen and chalcogen bonding, two sigma-hole interactions able to control the supramolecular organization of molecules in crystals, in a way similar to that of hydrogen bonding but with halogens (one sigma-hole) or chalcogens (two sigma-holes). While halogen bond interactions with Lewis bases are much stronger with the heavier elements (bromine, iodine), Arun demonstrated efficient halogen bond interaction with N-chlorobenzimidazoles allowing for the formation of polar chains and potential ferroelectric properties. The precise adaptation of chalcogen bond interactions in selenocyanates and seleno(telluro)acetylene derivatives allowed for the controlled formation of supramolecular rectangular boxes and infinite chains, as well as the proper orientation of diacetylene derivatives toward the topochemical synthesis of conducting polydiacetylene polymers. His work demonstrates unambiguously that chalcogen bonding can be as strong and predictable as the intensively investigated halogen bonding interactions.
The work was part of a collaborative ANR project (SIGMA-HOLE) involving also Dr Emmanuel Aubert and Pr. Enrique Espinosa, both at CRM2 at the Université de Lorraine (Nancy), who brought their expertise in the experimental and theoretical analyses of the electron density in such systems associated to the so-called non-covalent interactions. The research led to a range of high-quality publications in peer reviewed journals, including two Angew. Chem. Int. Ed. papers. Arun is currently a postdoctoral researcher at the NFMLab within the Politecnico di Milano with Pr. Guiseppe Resnati in Italy.
He wishes to thank the Foundation Rennes 1 and the board members of ISCR for considering his PhD work worthy of this honor. He is indebted to his PhD supervisors Dr. Marc Fourmigue, Dr. Ie-Rang Jeon and their co-worker Dr. Olivier Jeannin for their invaluable mentorship and enormous support during the thesis, without which this would not be possible. He is also grateful to his friends in Rennes, especially Dr. Soumen Mallick (Ecobio) and Dr. Shabina Ashraf (OSUR) for their time and support during the PhD.
- Rennes 1 Foundation news
- Arun Dhaka interview
- Ie-Rang Jeon, Univ Rennes, ISCR-CNRS UMR 6226, F-35000 Rennes, France
ie-rang [dot] jeonuniv-rennes [dot] fr
- Marc Fourmigué, Univ Rennes, ISCR-CNRS UMR 6226, F-35000 Rennes, France
marc [dot] fourmigueuniv-rennes [dot] fr
Published April 8, 2023