An ionically driven molecular IMPLICATION gate operating in fluorescence mode.
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.
Rurack
Knut
K
Div. I.5 Bioanalytik, Bundesanstalt für Materialforschung und -prüfung (BAM), Richard Willstätter Strasse 11, 12489 Berlin, Germany. knut.rurack@bam.de
Trieflinger
Christian
C
Koval'chuck
Anton
A
Daub
Jörg
J
D001896:Boron Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D015394:Molecular Structure; D011162:Porphobilinogen / Q000031:analogs & derivatives* / Q000737:chemistry; D011789:Quantum Theory
D001896:Boron Compounds; D005456:Fluorescent Dyes; D007477:Ions; C507544:dipyrromethene; D011162:Porphobilinogen