jp8b04814_si_001.pdf (485.04 kB)
Low-Molecular Push–Pull Pyrazoline Derivatives: Solvatochromic Effect and Theoretical Insights into Dye-based Molecular Engineering
journal contribution
posted on 2018-07-27, 00:00 authored by Karolina Anna Haupa, Adam Szukalski, Jarosław MyśliwiecIntermolecular
interactions between dyes and solvents are essential
in understanding a number of phenomena. In this contribution, we focused
on similarities and differences between two molecules belonging to
the same pyrazoline derivatives group: the small and rigid- 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP) molecule and the quite long and flexible
one of (4-(2-(1-phenyl-4,5-dihydro-1H-pyrazol-3-yl)vinyl)benzylidene)
malononitrile (PY-PhdiCN). We experimentally show and use theoretical
calculations to prove that extension of π-connector significantly
changes the electrostatic potential distribution, which results in
delocalization of negative charge along the whole donor group and
increases potential surface of interaction with solvent molecules
giving large spectral shifts. We also show that pyrazoline derivatives
are very effective and sensitive solvent indicators with long-time
stability.