Structure and Properties of 1,3,3-Trimethyl-6\u2032-chlorospiro[indoline-2,2\u2032-2H-chromene

A D Pugachev,N V Stankevich,B S Lukyanov,N I Makarova,I A Rostovtseva,A V Metelitsa,S M Aldoshin,V V Tkachev,G V Shilov

doi:10.1134/s1070363221070069

A D Pugachev, N V Stankevich + Show 7 more

Open Access

https://doi.org/10.1134/s1070363221070069

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Abstract

Indoline spiropyran containing an σ-acceptor chlorine atom in 6′ position of the 2H-chromene part of the molecule was synthesized and studied. The use of 1,2,3,3-tetramethyl-3H-indolium perchlorate as a starting compound made it possible to achieve higher product yields as compared to previous studies. The molecular structure of the compound was established by single crystal X-ray diffraction analysis. The features of the crystal structure and intermolecular interactions were investigated using CrystalExplorer17 software package. The photochromic behavior in acetonitrile solution was studied for the first time. It was found that the merocyanine form of spiropyran is characterized by an absorption maximum at 592 nm, which is 37 nm closer to the range of the “biological window” in comparison with the nitro-substituted analog.

Highlights

Spiropyrans represent one of the most interesting classes of organic compounds, the molecules of which can undergo reversible isomerization between the colorless spirocyclic and brightly colored merocyanine forms under the influence of various external factors
The search and study of spirocyclic structures modified with electronwithdrawing substituents other than nitro group is a promising area of investigations [9]
This article is devoted to the study of indoline spiropyran 1 containing a chlorine atom as an σ-acceptor substituent in 6′ position

Summary

Introduction

Spiropyrans represent one of the most interesting classes of organic compounds, the molecules of which can undergo reversible isomerization between the colorless spirocyclic and brightly colored merocyanine forms under the influence of various external factors. This article is devoted to the study of indoline spiropyran 1 containing a chlorine atom as an σ-acceptor substituent in 6′ position. The investigation of the compound 1 structure by 1H NMR showed that, due to the intense magnetic nonequivalent gem-dimethyl groups of the hetarene part, their hydrogen atoms are appeared as two three-proton singlet signals (1.16 and 1.29 ppm).

Results

Conclusion