On Raman optical activity sign-switching between the ground and excited states leading to an unusual resonance ROA induced chirality.

Autor:	Machalska E; Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Cracow Poland m.baranska@uj.edu.pl.; Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University Bobrzynskiego 14 30-348 Cracow Poland., Zajac G; Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University Bobrzynskiego 14 30-348 Cracow Poland., Baranska M; Faculty of Chemistry, Jagiellonian University Gronostajowa 2 30-387 Cracow Poland m.baranska@uj.edu.pl.; Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University Bobrzynskiego 14 30-348 Cracow Poland., Kaczorek D; Siedlce University, Faculty of Science 3 Maja Street No 54 08-110 Siedlce Poland robert.kawecki@uph.edu.pl., Kawęcki R; Siedlce University, Faculty of Science 3 Maja Street No 54 08-110 Siedlce Poland robert.kawecki@uph.edu.pl., Lipiński PFJ; Department of Neuropeptides, Mossakowski Medical Research Centre, Polish Academy of Sciences Pawińskiego 5 02-106 Warsaw Poland., Rode JE; Institute of Nuclear Chemistry and Technology 16 Dorodna-Street 03-195 Warsaw Poland j.dobrowolski@nil.gov.pl., Dobrowolski JC; Institute of Nuclear Chemistry and Technology 16 Dorodna-Street 03-195 Warsaw Poland j.dobrowolski@nil.gov.pl.
Jazyk:	angličtina
Zdroj:	Chemical science [Chem Sci] 2020 Nov 02; Vol. 12 (3), pp. 911-916. Date of Electronic Publication: 2020 Nov 02.
DOI:	10.1039/d0sc05345g
Abstrakt:	Raman optical activity (ROA) spectra recorded for a chiral naphthalene diimide derivative (nBu-NDI-BINAM) dissolved in a series of solvents exhibit strong solute to solvent induced chirality with: (1) dominating bands of solvents, (2) n Bu-NDI-BINAM resonance ROA (RROA) bands which are barely visible, (3) monosignate RROA Solvent spectra with an unexpected sign concordant with that of the ECD band of the resonant electronic state, (4) bisignate RROA bands for a few solvents, and (5) superposition of non-resonant and resonant ROA bands of the chiral solvents. The unusual ROA enhancement was explained in terms of resonance energy transfer with resonant Raman emission. The surprising RROA sign-switching was found to be due to specific conformational equilibria where one solute conformer dominates in the ground and the other in the first excited singlet state, and, the signs of the related ECD bands of these two conformers are opposite. Competing Interests: All the authors have given approval to the final version of the manuscript and declare no competing financial interest. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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