Light-up, colorimetric anion sensing and fingerprint visualization using the salicylaldehyde-based aggregation-induced emission-active phosphorescent Pt(II) complexes formed by restricting the molecular configuration transformations

Abstract

Developments of the AIE phosphorescent metal complexes are behind to these of pure organic AIEgens. Herein, Two AIE-active phosphorescent Pt(II) complexes applicating in anion detection and fingerprint visualization are reported. The distinct emission differences between dilute solutions and aggregated states manifest their AIE natures, supporting by the THF-H2O and film emission measurements. Importantly, it demonstrates that molecular configuration transformation (MCT) from the square planarity to the tetrahedron and the intramolecular rotation induce non-radiations of S1 and T1 states, thus almost no emissions of their dilute solutions. Upon aggregation or in rigid environment, the MCT and intramolecular rotation are restricted by themself or the matrix, radiative decays of excited states are aroused in aggregated or film states. Considering the acidity of the –OH unit in salicylaldehyde group, these complexes towards to fluoride ion detections including the naked-eye UV–Vis and light-up emission responses, anti-interference abilities, stoichiometry of 2 : 1, 10−7 M detection limits, deprotonation sensing mechanism and real sample test are fully covered and deeply investigated. Taking advantages of AIE natures, they are applicated in fingerprint detections featuring the fast speed, high resolution and multi-level characters. Eventually, the obtained results should expectedly offer valuable clues for phosphorescent AIE-active metal complexes and related application developing.