RESUMO
A series of novel ortho-terphenylene viologen derivatives (o-TPV2+) with through-space conjugation (TSC) via the combination of ortho-terphenylene skeletons with viologen structure is reported. Their optoelectronic properties can be adjusted by N-arylation or N-alkylation reactions. Compared with other viologen derivatives, o-TPV2+ not only exhibits strong photoluminescence but also retards the charge recombination process and stabilizes the diradical state without forming a quinoid structure due to the special TSC effect. Based on their special redox characteristics, o-TPV2+ was applied to the photocatalytic oxidative coupling of benzylamine with 96% yield. In addition, pTA-o-TPV2+ (tethered with p-toluic acid)-modified g-C3N4 was used for visible-light-driven hydrogen production for the first time, exceeding 15 times the rate over unmodified g-C3N4.
RESUMO
Two coordinated metallacycles (rhomboid for M1, hexagonal for M2) with selenoviologens (SeV2+ ) pendants were synthesized via coordination-driven hierarchical self-assembly. M1/M2 with rigid and discrete metallacyclic cores showed tunable optoelectronic properties due to strong π-π stacking and push-pull electron structures. Femtosecond transient absorption (fs-TA) revealed that the formation of macrocyclic structure can not only enhance the stability of radical cation, but also improve the efficiency of intramolecular charge transfer and produce a long-lived charge separation state. The electrochromic performances of M1/M2-based devices were exhibited to show decent radical stabilization. By using M1/M2 as the photocatalyst, the improved catalytic efficiency (>80 %) of visible-light-induced cross-dehydrogenative coupling (CDC) reactions was achieved due to the highly stable radical cations and long-lived charge separation states, which were also confirmed by fs-TA.
RESUMO
A series of novel bismuth-bridged viologen analogues, bismoviologens (BiV2+), synthesized through a combination of a bismuth atom and viologen skeleton is reported. Their optical and electrochemical properties were fine-tuned through the N-arylation or N-alkylation reactions. Bismolviologens not only showed good redox properties but also exhibited phosphorescence under ambient conditions (in air at room temperature). This phenomenon makes BiV2+ the first examples of phosphorescent viologen analogues reported to date. On the basis of the excellent and unique redox and optical properties of BiV2+, their electrophosphorochromic devices were fabricated. Furthermore, BiV2+ was used for the first time as both a photocatalyst and electron mediator in visible light-induced cross-dehydrogenative coupling reactions.
RESUMO
A series of chalcogen-containing carborane derivatives were synthesized through a one-pot reaction. The nonconjugated six-membered ring of carborane-fused disulfide (1) can be electrochemically reduced to a dithiolate derivative. The five-membered ring of carborane-fused chalcogenophenes (2-4) showed aromaticity and considerable σ-π conjugation. The dicarborane chalcogenides (5-7) showed intramolecular charge-transfer-induced emission. These chalcogen-containing carborane derivatives provided a useful platform to study the electron interaction systematically and shed some light on the design of carborane-based optoelectronic materials.
RESUMO
A series of novel persistent room-temperature phosphorescence (pRTP) materials (PEPCz) obtained via a combination of chalcogen atoms (O, S, Se, and Te) and a carbazolyl moiety is reported. Single crystal structure analysis revealed that PEPCz had similar molecular conformations and almost identical crystal packing. Mechanistic study showed that the intramolecular electronic coupling between the chalcogen atoms and π-units was responsible for tunable pRTP. The PEPCz were used not only to realize graphic encryption, but also to fabricate pRTP sensors for H2O2 and TNT detection.