Tetrathiafulvalene in a Perylene-3,4:9,10-bis(dicarboximide)-Based Dyad:  A New Reversible Fluorescence-Redox Dependent Molecular System

Abstract

A donor-acceptor dyad system involving tetrathiafulvalene (TTF) as donor attached by a flexible spacer to perylene-3,4:9,10-bis(dicarboximide) (PDI) as acceptor was synthesized and characterized. The strategy used the preliminary synthesis of an unsymmetrical PDI unit bearing an alcohol functionality as anchor group. Single-crystal analysis revealed a highly organized arrangement in which all PDI molecules are packed in a noncentrosymmetrical pattern. It was shown that the fluorescence emission intensity of the TTF-PDI dyad can be reversibly tuned depending on the oxidation states of the TTF unit. This behavior is attributed to peculiar properties of TTF linked to a PDI acceptor, which fluoresces intrinsically. Consequently, this dyad can be considered as a new reversible fluorescence-redox dependent molecular system.

Preparation and characterization of 3-(4,5-ethylenedithio-1,3-dithiol-2-ylidene)naphthopyranone: a luminescent redox-active donor–acceptor compound

“…Very recently, dyads and triads containing one or two TTF units covalently linked through a s-spacer to perylenediimide (PDI) and NDI have been reported. 7,8 The possibility to develop light intensity dependent molecular electronic switches with these systems has already been demonstrated in a porphyrin-PDI-porphyrin triad. 9 In the case of a TTF-PDI dyad, a reversible modulation of the emission fluorescence intensity in solution by either electron or energy transfer has been achieved.…”

“…9 In the case of a TTF-PDI dyad, a reversible modulation of the emission fluorescence intensity in solution by either electron or energy transfer has been achieved. 7 This dyad can therefore be considered as a new kind of molecular redox switch with a delayed optical response. 7 However, to date neither an example of a TTF unit linked by a p-conjugated spacer to a naphthalene or perylene moiety, nor a naphthalene or perylene core extended by 1,3-dithiol-2-ylidene units has been reported.…”

“…7 This dyad can therefore be considered as a new kind of molecular redox switch with a delayed optical response. 7 However, to date neither an example of a TTF unit linked by a p-conjugated spacer to a naphthalene or perylene moiety, nor a naphthalene or perylene core extended by 1,3-dithiol-2-ylidene units has been reported. In the latter case, analogous systems such as furano-quinonoid extended TTFs provide the basic synthetic strategy for the preparation of such compounds.…”

TTF‐Modified DNA

“…This shows that the PDI units are oriented in a twisted conformation and that a well-ordered helical structure is maintained in the modified region of the duplex. [57] As expected for a neutral form of tetrathiafulvalene, [3,53,58,59] no fluorescence was observed for single-stranded TTF-modified oligonucleotides (7,8) nor duplex 7*8. On the other hand, the low oxidation potential of TTF may, in principle, favor fluorescence quenching via photo-induced electron transfer, as recently applied in the construction of switchable fluorescent systems.…”

“…Starting from the known 2,3-bis(2-cyanoethylthio)-6,7-bis(pentylthio)tetrathiafulvalene (1), [53] bis-diol 2 was prepared by treatment with sodium in ethanol followed by alkylation with 2-chloroethanol. Reaction with 4,4'-dimethoxytrityl chloride gave the mono-protected intermediate 3, which was subsequently converted into the phosphoramidite derivative 4.…”