An Ionically Driven Molecular IMPLICATION Gate Operating in Fluorescence Mode

Abstract

An asymmetrically core-extended boron-dipyrromethene (BDP) dye was equipped with two electron-donating macrocyclic binding units with different metal ion preferences to operate as an ionically driven molecular IMPLICATION gate. A Na(+)-responsive tetraoxa-aza crown ether (R(2)) was integrated into the extended pi system of the BDP chromophore to trigger strong intramolecular charge transfer (ICT(2)) fluorescence and guarantee cation-induced spectral shifts in absorption. A dithia-oxa-aza crown (R(1)) that responds to Ag(+) was attached to the meso position of BDP in an electronically decoupled fashion to independently control a second ICT(1) process of a quenching nature. The bifunctional molecule is designed in such a way that in the absence of both inputs, ICT(1) does not compete with ICT(2) and a high fluorescence output is obtained (In(A)=In(B)=0-->Out=1). Accordingly, binding of only Ag(+) at R(1) (In(A)=1, In(B)=0) as well as complexation of both receptors (In(A)=In(B)=1) also yields Out=1. Only for the case in which Na(+) is bound at R(2) and R(1) is in its free state does quenching occur, which is the distinguishing characteristic for the In(A)=0 and In(B)=1-->Out=0 state that is required for a logic IMPLICATION gate and Boolean operations such as IF-THEN or NOT.

Input-Dependent Induction of Oligonucleotide Structural Motifs for Performing Molecular Logic

“…As a result, D1D2 and R1D2 always output 1 in acidic pH and 0 in basic pH, consistent with an ID logic gate that always identifies with the logic input of H + . 43 In the presence of H + alone, D1R2 forms a triplex and only releases a small amount of G-quadruplex. In this case, the catalytic activity is not so high (output 0), and thus D1R2 behaves as a two-input AND logic gate.…”

Squaraines as Reporter Units: Insights into their Photophysics, Protonation, and Metal‐Ion Coordination Behaviour

“…Such molecules are commonly referred to as "reconfigurable" molecular logic gates, that is, as systems in which it is possible to observe different logic expressions from one unique molecular entity. [60] Molecular chemosensing: From the point of view of chemosensing, the behaviour of most of the title compounds is far from being suitable, because of the considerably low selectivity observed. However, this is relatively common when using a poorly coordinating solvent such as acetonitrile.…”

A new coumarin based dual functional chemosensor for colorimetric detection of Fe3+ and fluorescence turn-on response of Zn2+

“…In addition, many useful integrated logic gates such as INHIBIT, half subtractor, half adder, full adder, and full subtractor with various single molecules have been exploited[15]. However, during literature surveys, very few IMPLICATION logic gate are reported so far[16]. Recently, there has been reported several molecular logic gates based on the structure of salicylidine Schiff base[17, 18].…”