Unique Chiro-optical Properties of the Weakly-2D (R-/S-MBA)2CuBr4 Hybrid Material

Das, R and Hossain, M and Mahata, A and Swain, D and De Angelis, F and Santra, PK and Sarma, DD (2023) Unique Chiro-optical Properties of the Weakly-2D (R-/S-MBA)2CuBr4 Hybrid Material. In: ACS Materials Letters . pp. 1556-1564.

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Abstract

We establish that the formally 0D (R-/S-MBA)2CuBr4, containing R-/S-α-methyl benzylamine (R-/S-MBA) connected to highly distorted CuBr4 tetrahedral units in alternating layers, possesses extraordinary chiro-optical properties. The concentration and path length-independent chiral anisotropy factor, gCD, for this compound is the highest in the orange-red part of the visible spectrum reported so far from any hybrid material, arising from a chirality transfer from the organic component to the inorganic layer through the extensive asymmetric hydrogen bonding network and electronic coupling, driving the CuBr4 tetrahedral units to follow the 21-screw axis. This sensitivity in the orange-red part of the visible spectrum is achieved by incorporating bromine in the copper coordination sphere, which significantly red-shifts the band edge absorption to ∼710 nm compared to ∼490 nm reported for the chloride analogue. DFT/TDDFT calculations allow us to understand the underlying electronic structure responsible for its remarkable optical properties. We find that this compound gets a partial 2D character, crucial for its broadband chiro-optical properties, arising from Cu-Br···Br-Cu interactions connecting the otherwise isolated CuBr4 units. © 2023 American Chemical Society.

Item Type:	Journal Article
Publication:	ACS Materials Letters
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society.
Keywords:	Absorption spectroscopy; Chlorine compounds; Citrus fruits; Copper compounds; Electronic structure; Hybrid materials; Hydrogen bonds; Red Shift, Alternating layers; Anisotropy factor; Benzylamines; Chirality transfer; Chirooptical properties; Hybrids material; Orange-red; Organic components; Pathlengths; Visible spectrums, Bromine compounds
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	14 Jun 2023 12:52
Last Modified:	14 Jun 2023 12:52
URI:	https://eprints.iisc.ac.in/id/eprint/81909

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