Stilbene isothiocyanates as potential fluorescent tagging agents

Ultra-sensitive fluorescent sensor for Hg2+ based on a donor-acceptor-donor framework

A new fluoroionophore [E-4,4'-di(N-(2-pyridyl)amino)stilbene, E1] with a donor-acceptor-donor framework, which features a central stilbene (acceptor) fluorophore and two terminal pyridylamino (donor) ionophores, is reported. The probe displays an ultrasensitive fluorescence quenching response toward Hg(2+) in H(2)O/THF. Coordination of Hg(2+) to E1 affords a 2:1 complex, enabling the detection of Hg(2+) at a concentration as low as 4.4 × 10(-14) M. The interactions between the two species have been thoroughly characterized with UV-vis absorption spectroscopy, fluorescence spectroscopy, and nuclear magnetic resonance spectroscopy. Density functional theory calculations provide further insights into the nature of the fluorescence quenching response. In contrast, a fluorescent molecule with the donor-acceptor architecture, E-4-(N-(2-pyridyl)amino)stilbene (E4), exhibits a greatly attenuated fluorescence quenching response toward Hg(2+).

Polycyclic aromatic isothiocyanate compounds as fluorescent labeling reagents

Polycyclic aromatic isothiocyanates were synthesized in an attempt to produce new fluorescent agents for protein labeling and for use in microanalytical techniques. The relative fluorescence of these reagents, the required intermediates, and the derivatives were established. Of the compounds evaluated, the 9-acridine derivatives were the most promising.