Chromene “Lock”, Thiol “Key”, and Mercury(II) Ion “Hand”: A Single Molecular Machine Recognition System

Abstract

A regenerative, molecular machine-like "ON-OFF-ON" chemosensor based on a chromene molecule with the pyran ring "OFF-ON-OFF" cycle is reported for the first time. It behaves as a molecular lock that requires a thiol "key" to open the lock and a mercury(II) ion "hand" that unlatches the key for unsheathing the key to close the lock.

An ‘OFF–ON’ fluorescent probe for specially recognize on Cys and its application in bioimaging

“…Colorimetric and fluorescent methods to detect thiols have received increasing attention since they are simple, sensitive, efficient and applicable for intracellular detection among the various strategies [17]. Many mechanisms were based on Michael addition [18][19][20][21][22][23][24][25][26], cyclization with aldehydes [27][28][29][30], ligand displacement of metal complexes by thiols [31][32][33][34] and cleavage reaction induced by thiols [35][36][37][38]. The sensors for thiol utilizing thiol addition to the maleimide moiety have been developed when Sippel reported N-(4'-(7-diethylamino-4-methylcoumarin-3-yl)phenyl)maleimide as one of the first examples of thiol probes in 1981 [39][40].…”

Styryl-BODIPY based red-emitting fluorescent OFF–ON molecular probe for specific detection of cysteine

“…Selective detection of biological thiols, such as cysteine, homocysteine and glutathione, have attracted much attention due to the pivotal role of these -SH containing molecules in physiological pathways (Chen et al, 2010a;Weh et al, 2007;Tang et al, 2007;Refsum et al, 2004;Hong et al, 2009;Lee et al, 2010;Huo et al, 2010;Shang and Dong, 2009;Yu et al, 2007;Huang et al, 2010;Yi et al, 2009;Wang et al, 2009). For example, increased white cell cysteine concentrations are only observed in individuals with cystinosis.…”

Bis-Benzimidazolyl Diamide Based Fluorescent Probe for Copper(II): Synthesis, Structural and Fluorescence Studies

“…Several molecular machines have been developed that have a recognition system based on a lock and key mechanism [27,54]. It was therefore of interest to find if the present system possesses such a recognition system or not.…”