Conformationally Rigid Ethynylene−Cumulene Conjugated Aromatic [30] Heteroannulenes with NIR Absorption: Synthesis, Spectroscopic and Theoretical Characterization.

Krushna Chandra, Sahoo and Meenakshi, S. Kumaraswami and Usharani, D. and Harapriya, Rath (2019) Conformationally Rigid Ethynylene−Cumulene Conjugated Aromatic [30] Heteroannulenes with NIR Absorption: Synthesis, Spectroscopic and Theoretical Characterization. Journal of Organic Chemistry, 84. pp. 5203-5212.

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Abstract

Two hitherto unknown conformationally rigid Hückel aromatic ethynylene−cumulene conjugated [30] heteroannulenes have been synthesized and characterized. A thorough solution-state spectroscopic characterization, combined with in-depth theoretical calculations, has been performed to arrive at the proposed geometry of the macrocycles. The most stable optimized structures for the free base form of both the macrocycles showed absolute planar geometries without any ring inversion with mean plane deviation (MPD) values of 0.00 and 0.00 Å, respectively, in accordance with the NMR spectroscopic observations. The induced correspondence of rigid ethynylene−cumulene moieties leading to near-infrared (NIR) absorption in neutral and protonated forms of macrocycles is the important highlight of this article. This noteworthy finding has been supported by DFT-level theoretical calculations. There is an increasing pursuit in designing such NIRabsorbing/- emitting systems due to their immense applications in medicine and biology for recognizing and transportation of various substrates. The geometry of the novel 30π aromatic heteroannulenes shows promise for evolution of such novel systems in near future.

Item Type:	Article
Uncontrolled Keywords:	aromatic ethynylene, near-infrared (NIR) absorption
Subjects:	500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 24 Organic Chemistry
Divisions:	Food Safety Analytical Quality Control Lab
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	03 Jun 2019 05:56
Last Modified:	03 Jun 2019 05:56
URI:	http://ir.cftri.res.in/id/eprint/14115

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