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Thermo‐ and photochromic dyes: Spiro(indolinebenzopyrans). 2 —detailed assignment of the 1 H NMR spectra and structural aspects of the closed form of 1,3,3‐trimethylspiro(indoline‐2,2′‐benzopyrans)
Author(s) -
Keum SamRok,
Lee KiBong,
Kazmaier Peter M.,
Manderville Richard A.,
Buncel Erwin
Publication year - 1992
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260301119
Subject(s) - chemistry , indoline , homonuclear molecule , photochromism , epimer , proton nmr , nuclear magnetic resonance spectroscopy , cyclobutene , nmr spectra database , spectral line , carbon 13 nmr , molecule , stereochemistry , photochemistry , organic chemistry , physics , astronomy , ring (chemistry)
The proton NMR assignments for a series of 12 thermo‐ and photochromic 1,3,3‐trimethylspiro(indoline‐2,2′‐benzopyrans) dyes is reported. All of the protons in the dye molecule were assigned through a combination of homonuclear decoupling experiments and correlation spectroscopy. The relative stereochemistry of the indolino gem ‐dimethyl groups was assigned so that, for the S ‐epimer, the pro‐ R methyl was found to resonate at 1.24 ppm while the pro‐ S methyl appeared at 1.37 ppm for compound 1.