Naphthalene-Like Unit That Induces Strong Optical Anisotropy in C10H8NO2Br and C10H8NO2Br·H2O

Yaoguo Shen; Yingwu Zhou; Xiaoling Xue; Guofa Dong

doi:10.1021/acs.inorgchem.3c01197

Naphthalene-Like Unit That Induces Strong Optical Anisotropy in C₁₀H₈NO₂Br and C₁₀H₈NO₂Br·H₂O

Inorg Chem. 2023 Jun 5;62(22):8482-8486. doi: 10.1021/acs.inorgchem.3c01197. Epub 2023 May 19.

Authors

Yaoguo Shen¹, Yingwu Zhou¹, Xiaoling Xue¹, Guofa Dong²

Affiliations

¹ College of Physics and Electronic Information Engineering, Minjiang University, Fuzhou, Fujian 350108, China.
² Fujian Key Laboratory of Functional Marine Sensing Materials, College of Materials and Chemical Engineering, Minjiang University, Fuzhou 350108, China.

PMID: 37204340
DOI: 10.1021/acs.inorgchem.3c01197

Abstract

Two metal-free birefringent crystals, C₁₀H₈BrNO₂ and C₁₀H₈BrNO₂·H₂O, which contain a new birefringence-active [C₁₀H₈NO₂]⁺ gene, were synthesized via a mild solution evaporation method. In their crystal structures, the π-conjugated naphthalene-like [C₁₀H₈NO₂]⁺ groups are basically aligned, which induces high optical anisotropy; i.e., the title compounds exhibit large birefringences of 0.36 and 0.41 at 550 nm according to first-principles calculations. Moreover, the UV-vis-near-IR diffuse-reflectance spectra suggest that they have similar optical band gaps. Structural analysis and theoretical calculations show that the [C₁₀H₈NO₂]⁺ unit is responsible for the good optical anisotropy. These results make the naphthalene-like motif a good structural gene to search for new birefringent crystals.