Ultrafast Excited State Dynamics Of Twisted Aromatics

Hariharan, Mahesh

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https://hdl.handle.net/2142/111571 Copy

Description

Title

Ultrafast Excited State Dynamics Of Twisted Aromatics

Author(s)

Hariharan, Mahesh

Issue Date

2021-06-24

Keyword(s)

Dynamics and kinetics

Abstract

\begin{wrapfigure}{l}{0pt} \includegraphics[scale=0.3]{Figure.eps} \end{wrapfigure} Self-assembling of organic chromophoric systems into elegant supramolecular architectures with emergent properties has received prodigious attention in recent years.$^{1}$ In the first example (Figure), a naphthalene-naphthalimide donor-acceptor (D-A) dyad assembled into segregated D-A stacks in the crystalline state. The photo-induced charge separated state in the aggregate state lasts 10,000 times longer than the monomeric dyad. The femtosecond transient absorption spectra depicted the spectroscopic signature for naphthalene dimer radical cation indicating the migration of charges through the stacks.$^{1}$ In the second example, we report the crystalline evidence for Greek cross-dipole ($\alpha$=$90^{\circ}$) stacking of 1,7-dibromoperylene-3,4,9,10-tetracarboxylic tetrabutylester (PTE-Br2) displaying null excitonic coupling and thereby monomeric optical behavior.$^{2}$ In the third example, we showcase a radial assembly of 1,8-dibromonaphthalene(2,6-diisopropylphenyl)imide (NIBr2) in crystalline phase driven by hexabromine synthon.$^{4}$ NIBr2 exhibits ultrafast intersystem crossing$^{3-5}$ and solid-state room temperature phosphorescence. References: $^{1}$ A. R. Mallia, P. S. Salini, M. Hariharan, J. Am. Chem. Soc., 137 (2015) 15604. $^{2}$ E. Sebastian, A. M. Philip, A. Benny, M. Hariharan, Angew. Chem., Int. Ed., 57 (2018) 15696. $^{3}$ M. A. Niyas, R. Ramakrishnan, V. Vijay, E. Sebastian, M. Hariharan, J. Am. Chem. Soc, 141 (2019) 4536. $^{4}$ K. Nagarajan, A. R. Mallia, K. Muraleedharan, M. Hariharan, Chem. Sci., 8 (2017) 1776. $^{5}$ M. P. Lijina, A. Benny, R. Ramakrishnan, N. Nair, M. Hariharan, J. Am. Chem. Soc. 41 (2020), 17393.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Permalink

http://hdl.handle.net/2142/111571

DOI

10.15278/isms.2021.RJ01

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