Solvatochromic Study of Highly Fluorescent Alkylated Isocyanonaphthalenes, Their π‐Stacking, Hydrogen‐Bonding Complexation, and Quenching with Pyridine

Abstract

Mono- and dialkylated derivatives of 1-amino-5-isocyanonaphthalene (ICAN) were studied as new members of a multifunctional, easy-to-prepare fluorophore family, which showed excellent solvatochromic properties. The monoallyl derivative and the starting ICAN exhibited strong fluorescence quenching in the presence of small amounts of pyridine. The formation of a hydrogen-bonded ground-state pyridine complex was detected; however, analysis of quantum chemical calculations suggested the presence of an additional π-stacked pyridine complex. The Stern-Volmer plot of the quenching process exhibited a downward curvature and after reaching a minimum the fluorescence intensity increased back to a significant level at high pyridine concentrations. Significant fluorescence was observed even in pure pyridine. A new mechanism and a simple mathematical equation were derived to explain the downward curvature and the remaining fluorescence by the formation of a fluorescent π-stacked complex.

An acrylated isocyanonaphthalene based solvatochromic click reagent: Optical and biolabeling properties and quantum chemical modeling

“…The extinction coefficient corresponding to this peak varies between ε ¼ 5700 M À1 cm À1 in water and ε ¼ 9100 M À1 cm À1 in dichloromethane. The double peak structure of the band is characteristic for the ICAN derivatives containing free NH-hydrogen [33] and is most probably due to the superposition of the NH bending vibrational transition onto the absorption spectrum. It should be noted that the experimental UVeVis spectra are in very good agreement with the calculated spectra ( Fig.…”

“…We employed DFT and TDDFT for geometry optimizations at the ground and excited states respectively. The chosen functional was the M06 [36] with the TZVP basis set [37] because it is able to describe some amount of the dispersion forces in contrast to B3LYP [38] and CAM-B3LYP [39] which was found to be necessary to properly optimize p-stacked structures [33]. The calculations were done using the IEF-PCM solvent model [40e43].…”

Solvatochromic isocyanonaphthalene dyes as ligands for silver(I) complexes, their applicability in silver(I) detection and background reduction in biolabelling

“…[37] We employed DFT and TDDFT for geometry optimizations at the ground and excited states respectively. The chosen functional was the M06 [38] with the TZVP basis set [39] because it is able to describe some amount of the dispersion forces in contrast to B3LYP [40] and CAM-B3LYP [41] which was found to be necessary to properly optimize π-stacked structures [33] . On the silver atom we used the CRENBL ECP/basis [42] .…”

Fényemittáló vegyületek előállítása és vizsgálata

“…Ezt egy piridinnel hidrogénkötésen keresztül kapcsolódó nem fluoreszkáló alapállapotú komplex és egy fluoreszcenciát kibocsátó ð-szendvicskomplex egyidejû jelenlétével magyaráztuk, a két forma között egyensúlyt feltételeztünk. 9 …”