Conformational analysis by UV spectroscopy: the decisive contribution of environment-induced electronic Stark effects

Abstract

The correlation between experimental electronic transitions and calculated electric fields leads to precise conformational assignments and opens up the possibility of interpreting electronic spectra in a quantitative manner at the wavenumber scale.

Mechanical Tuning of Aggregated States for Conformation Control of Cyclized Binaphthyl at the Air–Water Interface

“…Generally, molecular conformations are identified using spectroscopic methods such as NMR, , Fourier transform infrared (FT-IR), ultraviolet–visible (UV–vis), , circular dichroism (CD), , and scanning tunneling microscopy. , In particular, we have used CD measurement on monolayers of binaphthyl derivatives ,, because their CD spectra can be obtained at low concentrations (less than 10 –5 M) and sensitively reflect conformational changes. , Conformational variation in binaphthyl derivatives can be equated with changes in their dihedral angle φ between naphthyl groups and clearly depend on the effects of substituents, − solvents, and aggregated states. , Control of the states of molecular aggregation and chirality has mostly been accomplished in solution by controlling the mixing ratio of good and poor solvents − , or by varying the solvent and/or temperature . We have previously synthesized amphiphilic plier-type binaphthyls and tuned their dihedral angles by mechanical compression at the air–water interface. , More recently, the molecular conformations and aggregated states of bisbinaphthyldurene (BBD) having two binaphthyl paddles on each side of the central phenyl ring have been controlled by mixing with appropriate lipids at the air–water interface .…”

“…Generally, molecular conformations are identified using spectroscopic methods such as NMR, 22,23 Fourier transform infrared (FT-IR), 24 ultraviolet−visible (UV−vis), 25,26 circular dichroism (CD), 16,17 and scanning tunneling microscopy. 27,28 In particular, we have used CD measurement on monolayers of binaphthyl derivatives 16,17,29 because their CD spectra can be obtained at low concentrations (less than 10 −5 M) and sensitively reflect conformational changes.…”