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Swapping Circularly Polarised Luminescence of Eu(III)‐Binaphthyl Hybridized Luminophore with and without Oxymethylene Spacer
Author(s) -
Hara Nobuyuki,
Okazaki Mamoru,
Shizuma Motohiro,
Marumoto Shinsuke,
Tajima Nobuo,
Fujiki Michiya,
Imai Yoshitane
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201701460
Subject(s) - luminophore , luminescence , sign (mathematics) , ring (chemistry) , chemistry , stereochemistry , crystallography , physics , optics , mathematics , organic chemistry , mathematical analysis
Chiroptical signs in circularly polarised luminescence (CPL) of Eu(III) luminophores coordinated to C 2 ‐symmetric binaphthyl ring carrying carboxylic acids, ( R )‐ 1 (and ( S )‐ 1 )) and ( R )‐ 2 (and ( S )‐ 2 )) were inverted by inserting two oxymethylene spacers between the ring and the acids. The subtle difference in reorganization between ( R )‐ 1 and ( R )‐ 2 causes the apparent CPL sign‐swapping characteristics. We assume that ( R )‐ 2 is more likely to undergo this reorganization rather than ( R )‐ 1 because of the highly flexible spacer and vice versa. The subtle difference in the rotational freedom of the ligands with and without the two spacers causes the opposite CPL signs although ( R )‐ 1 /Eu and ( R )‐ 2 /Eu had the same CD sign in the ground state. This was proven by experimental and theoretical data.