Unveiling versatile properties of a N,N′-bis(biphenyl)amino tailored stilbene-terpyridyl conjugate and its multifunctional role in fluorescence sensing

Design and development of a multifunctional donor-π-acceptor type stilbene-N,N′-bis(biphenyl) conjugated terpyridine, 4′-(4-{2-[4-(dibiphenyl-4-ylamino)]phenyl-ethenyl}phenyl)-2,2′:6′,2″-terpyridine, has been accomplished and unequivocally characterized. The emissive push-pull congener exhibits fascinating photophysical features including solvatochromism and vapochromism, enabling detection of selective volatile organic compounds (VOCs). Not only that, remarkable chemosensing properties for explosive nitroaromatics (NACs) and Cu²⁺ ions are also displayed. It can effectively detect picric acid (PA) in ppm level in solution through photo-induced electron transfer (PET) quenching process. More importantly, trace detection of PA vapor is also demonstrated as visualized by bare eyes. Additionally, the probe has a high selectivity towards hazardous Cu²⁺ with detection limit in ppb level. Moreover, an IMPLICATION molecular logic gate is constructed to achieve ON/OFF/ON behavior utilizing Cu²⁺ and S²⁻ as inputs and fluorescence response as the output. Lastly, as a prospective onsite detection kit, the test paper experiment shows the practical usefulness of the probe for the quick and apparent detection of Cu²⁺. Thus, the designed stilbene-N,N′-bis(biphenyl) conjugated terpyridine truly acts as a multifunctional single molecule.