A pair of regio-isomeric compounds acting as molecular logic gates with different functions

A Tutorial Review on the Fluorescent Probes as a Molecular Logic Circuit-Digital Comparator

The rapid progress in the field of fluorescent probes and fluorescent sensing material extended this research area toward more complex molecular logic gates capable of carrying out a variety of sensing functions simultaneously. These molecules are able to calculate a composite result in which the analysis is not performed by a man but by the molecular device itself. Since the first report by de Silva of AND molecular logic gate, all possible logic gates have been achieved at the molecular level, and currently, utilization of more complicated molecular logic circuits is a major task in this field. Comparison between two digits is the simplest logic operation, which could be realized with the simplest logic circuit. That is why the right understanding of the applied principles during the implementation of molecular digital comparators could play a critical role in obtaining logic circuits that are more complicated. Herein, all possible ways for the construction of comparators on the molecular level were discussed, and recent achievements connected with these devices were presented.

A dithienosilole-based fluorescent chemosensor for multiple logic operations at the molecular level

A chemosensor consisting of two terpyridines covalently linked to a dithienosilole unit (1) has been synthesized, and its optical and metal sensing properties have been investigated. Due to the metal-organic coordination function, 1 can bind with many transition metal ions and display different fluorescence responses that cause it to function as a "turn-off" fluorescent chemosensor. A significant bathochromic shift in the fluorescence spectra is observed in the presence of Zn(2+). Meanwhile, the emission of 1 is weakened upon exposure to Ag(+) and Fe(2+) and completely quenched by Ni(2+), Co(2+), and Cu(2+). Based on the observed results, several logic gates, such as XNOR, INHIBIT, and IMPLICATION, have been achieved by controlling the chemical inputs.

3(2H)-Furanone as a promising scaffold for the synthesis of novel fluorescent organic dyes: an experimental and theoretical investigation

Novel 3(2H)-furanone compounds have been synthesised and characterized. Experimental and theoretical studies indicated that these compounds exhibit interesting solvatochromic effects.

A novel fluorescent pH probe with valuable pKabased on a twisted intramolecular charge transfer mechanism, and its applications in cell imaging

A novel TICT-mechanism based pH probe with valuable pK_aof 5.32 has been developed. It is a promising visualizing agent for lysosomes in intracellular application.

Sensor activity and logic behaviour of PET based dihydroimidazonaphthalimide diester

An ester terminated dihydroimidazonaphthalimide as multi-functional logic device is presented. Due to the optical changes as a function of pH this simple molecule is able to act as a molecular pH metre, a digital comparator and a half-adder. It was demonstrated that the dihydroimidazonaphthalimide comparator could be used as a fundamental element of an optical device for control of pH windows. Also, the ability of the device to detect metal ions in DMF and in water/DMF (3:1, v/v) at different pHs has been evaluated by monitoring the changes of its fluorescence intensity. Among the tested metal ions (Cd(2+), Co(2+), Cu(2+), Fe(3+), Ni(2+), Pb(2+), Zn(2+), Bi(3+), Hg(2+) and Ag(+)) only Fe(3+) and Bi(3+) were efficiently detected. In water/DMF (3:1, v/v) XOR and XNOR logic gates are presented using pH and Fe(3+) as chemical inputs based on encoding binary digits of logical conventions.

A colorimetric and fluorescent dual probe for specific detection of cysteine based on intramolecular nucleophilic aromatic substitution

4-Nitro-1,8-naphthalic anhydride (NNA) was used to distinguish cysteine from homocysteine and other potentially interfering thiols through a novel sequential substitution mechanism. The discrimination involves a blue-fluorescent thioether formation via nucleophilic aromatic substitution of the nitro group by thiol, followed by a second intramolecular nucleophilic aromatic substitution of alkylthio with the amino group to give the green-fluorescent 4-amino derivative. NNA is highly selective towards Cys, and the detection limit of Cys by this method is 0.3 μM.