Electrochemically Triggered Energy Release from an Azothiophene-Based Molecular Solar Thermal System

Molecular solar thermal (MOST) systems combine solar energy conversion, storage, and release in simple one-photon one-molecule processes. Here, we address the electrochemically triggered energy release from an azothiophene-based MOST system by photoelectrochemical infrared reflection absorption spectroscopy (PEC-IRRAS) and density functional theory (DFT). Specifically, the electrochemically triggered back-reaction from the energy rich (Z)-3-cyanophenylazothiophene to its energy lean (E)-isomer using highly oriented pyrolytic graphite (HOPG) as the working electrode was studied. Theory predicts that two reaction channels are accessible, an oxidative one (hole-catalyzed) and a reductive one (electron-catalyzed). Experimentally it was found that the photo-isomer decomposes during hole-catalyzed energy release. Electrochemically triggered back-conversion was possible, however, through the electron-catalyzed reaction channel. The reaction rate could be tuned by the electrode potential within two orders of magnitude. It was shown that the MOST system withstands 100 conversion cycles without detectable decomposition of the photoswitch. After 100 cycles, the photochemical conversion was still quantitative and the electrochemically triggered back-reaction reached 94 % of the original conversion level.

Sexually dimorphic characters and shared aposematic patterns mislead the morphology-based classification of the Lycini (Coleoptera: Lycidae)

The Lycini (Elateroidea: Lycidae) contains > 400 species placed in four typologically based genera and numerous subgenera. We assembled a mito-ribosomal dataset representing ~100 species from the whole range and recovered a phylogeny rejecting Lycus and Lycostomus as polyphyletic assemblages. The male-specific wide elytra and elytral thorns are identified in unrelated Neolycus and Lycus. The morphological similarity based on sexual dimorphism and aposematic patterns defined terminal clades and misled the genus-rank classification. We delimit Neolycus, Rhyncheros reinst. name (= Thoracocalon syn. nov. = Lyconotus syn. nov.), LipernesLycostomus, Haplolycus and Lycus. Demosis and six subgenera of Lycus are synonymized with Lycus. Celiasis Laporte, 1840 is kept in the classification as a nomen dubium until any specimen is available. The deep lineages are known from the Americas and Asia. Africa was colonized by Lycus and Haplolycus. Each specific aposematic pattern occurs in a limited range, and the similar body shape and coloration evolved in unrelated sympatrically occurring lineages. High intraspecific polymorphism is putatively a result of the adaptation of various populations to local mimetic assemblages. Therefore, the delimitation of many phenotypically diverse species should be investigated.