Design and Electronic Structure of New Styryl Dye Bases: Steady-State and Time-Resolved Spectroscopic Studies

Abstract

A comprehensive investigation of the electronic structure and fast relaxation processes in the excited states of new styryl base-type derivatives was performed using steady-state, pico-, and femtosecond time-resolved spectroscopic techniques. Linear photophysical parameters of new compounds, including steady-state absorption, fluorescence, and excitation anisotropy spectra, were obtained in a number of organic solvents at room temperature. A detailed analysis of the fluorescence lifetimes and ultrafast relaxation processes in the electronically excited state of the styryl bases revealed an important role of solvate dynamics and donor-acceptor strength of the molecular structures in the formation of their excited state absorption spectra. Experimental data were in good agreement with quantum chemical calculations at the time dependent density functional theory level, combined with a polarizable continuum model.

Electronic Nature of Nonlinear Optical Properties of a Symmetrical Two-Photon Absorbing Fluorene Derivative: Experimental Study and Theoretical Modeling

“…The relaxation processes in 1 were investigated by a femtosecond transient absorption pump–probe technique in nonpolar (TOL) and polar (ACN) aprotic solvents over a broad spectral range. The induced changes in the optical density, Δ D , were measured as a function of time delay, τ D , between the probe and pump pulses and of the probe wavelength, λ p , and are presented in Figure .…”

“…The second beam at 800 nm pumped into an OPA TOPAS-800 fs (Coherent, Inc.) with a broad tuning range was used as the fluorescence-quenching beam. The transient absorption pump–probe setup was comprehensively described in refs and . Briefly, the output of the Ti:sapphire regenerative amplifier, Legend F-1K-HE (Coherent, Inc.), at a wavelength of 800 nm, E p ≈ 1 mJ, τ p ≈ 140 fs (fwhm), and a repetition rate of 1 kHz, was split into two parts.…”

Nature of Linear Spectral Properties and Fast Electronic Relaxations in Green Fluorescent Pyrrolo[3,4-c]Pyridine Derivative

“…The nature of fast intramolecular relaxation processes and time-resolved ESA spectra of HPPT were investigated by a femtosecond transient absorption pump-probe methodology described in detail previously [ 39 , 40 ]. In short, the output of a femtosecond laser system with 1 kHz Ti:Sapphire regenerative amplifier (Legend F-1K-HE, Coherent, Santa Clara, CA, USA) tuned to 800 nm with corresponding pulse energy, ≈ 1 mJ, and pulse duration, ≈ 140 fs, was divided in two parts.…”

Rational Design of Hemicyanine Langmuir Monolayers by Cation-Induced Preorganization of Their Structure for Sensory Response Enhancement

“…Crown ethers, of which the 50th anniversary of their discovery by Charles Pedersen was celebrated last year, still remain the most studied. , Proper implementation of a compound as a sensory platform requires not only the ability to form complexes with a desired analyte but also to exhibit some sort of a detectable response, such as changes of optical and/or fluorescent characteristics. This approach requires the presence of chromo- and/or fluorophoric moiety in a sensory molecule, optical properties of which should change upon reaction with an analyte. − In this regard, hemicyanine dyes are especially interesting, due to the ease of chemical modification by crown-ether moieties, aliphatic chains, and other functional groups. ,− It is important to note that in the majority of solid-state sensors, only the molecules near the interface are accessible for the analyte, thus giving rise to a demand for rational design of novel ultrathin receptor films. In the case of estimating the content of water-soluble salts of toxic metals in water, operation in aqueous media is also required.…”