Design and Synthesis of New Bithiophene Based Planar AIE Red Light Emitters: A Detailed Theoretical and Experimental Analysis. Issue 13 (30th March 2022)

• Record Type: Journal Article
• Authors: Mohan, Makesh; Nagarajan, Satyanarayan M.; Trivedi, Darshak R.
• Is Part Of: ChemistrySelect. Volume 7:Issue 13(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-30
• Subjects: AIE** -- Density functional calculations -- Fluorescence -- Red-emission -- Reorganization energy; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202103173
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Bithiophene core with −CN substituted pyrazole and imidazole side chains yielding B1, B2, and B3 have been designed and synthesized viz Schiff's base condensation reaction. Molecules, at their solid‐state exhibited red‐light emission supporting AIE mechanism. The series exhibited the highest relative quantum yield of value 18.66 % by B1 with the lowest recorded for B3 exhibiting 2.4 %. DFT results reveal the synthesized molecules at their optimized ground state adopt a planar structure. Theoretical calculation further validates the molecules to adopt a slip‐stacking type of molecular packing arrangement at its condensed state, conducive for AIE. A large π‐π stacking distance between the lattice plane of 3.4 Å, 3.6 Å and 3.5 Å possessed by B1, B2, and B3 respectively, favors AIE. Computational calculation on electron and hole reorganization energy reveals the effective role of two −CN groups in altering the hole mobility in comparison with the other molecules in the series. Abstract : AIE properties of cyano substituted bithiophene core with pyrazole and imidazole units as red light emitters were studied. Theoretical study confirms the ability of the molecules to possess a slip‐stacking mode of molecular packing at its condensed state, favoring AIE. A large π‐π stacking distance between the lattice planes in the series well supports AIE phenomenon. The effective role of two −CN groups in altering the hole mobility were realized by studying the reorganization energies of the system.