We report on the platinum complexes trans-Pt(BODIPY)(8-ethynyl-BODIPY)(PEt) (EtBPtB) and trans-Pt(BODIPY)(4-ethynyl-1,8-naphthalimide)(PR) (R = Et, EtNIPtB-1; R = Ph, EtNIPtB-2), which all contain two different dye ligands that are connected to the platinum atom by a direct σ bond. The molecular structures of all complexes were established by X-ray crystallography and show that the different dye ligands are in either a coplanar or an orthogonal arrangement. π-stacking and several CH···F and short CH···π interactions involving protons at the phosphine substituents lead to interesting packing motifs in the crystal. The complexes feature several strong absorptions (ε = 3.2 × 10-5.5 × 10 M cm) that cover the regime from 350 to 480 nm (EtNIPtB-1 and EtNIPtB-2) or from 350 to 580 nm (EtBPtB). Besides the typical absorption bands of both kinds of attached dyes, they also feature an intense band near 400-420 nm, which is assigned by time-dependent density functional theory calculations to a higher-energy transition within the ethynyl-BODIPY (EtB) ligand or to charge transfer between the BODIPY (B) and naphthalimide (NI) chromophores. All complexes show dual fluorescence and phosphorescence emission from either the B (EtNIPtB-1 and EtNIPtB-2) or EtB (EtBPtB) ligand with a maximum phosphorescence quantum yield of 41% for EtNIPtB-1. The latter seems to be the highest reported value for room temperature phosphorescence from a BODIPY dye. The complete quenching of the emission from the chromophore absorbing at the higher energy and the appearance of the corresponding absorption bands in the fluorescence and phosphorescence excitation spectra indicate complete and rapid energy transfer to the chromophore with the lower-energy excited state, i.e., EtNI → B in EtNIPtB-1 and EtNIPtB-2 and B → EtB in EtBPtB. The latter process was further investigated by transient absorption spectroscopy, indicating that energy transfer is complete within 0.6 ns. EtNIPtB-1 catalyzes the photooxidation of 1,5-dihydroxynaphthalene with photogenerated O to Juglone at a much faster rate than methylene blue but with only modest quantum yields of 37% and with the onset of photodegradation after 60 min.

With its 3d 10 valence electron configuration Ni(0) is isoelectronic with Cu(I). While many Cu(I) complexes emitting from metal-to-ligand charge transfer (MLCT) excited states have been explored, the number of luminescent Ni (0) complexes known to date is very limited. Ni(0) is typically stabilized by carbonyls, phosphines or isocyanides due to the -acceptor properties of these ligands, and photoluminescence has been reported in a few selected cases that are reviewed herein. Recent studies indicate that chelating isocyanide ligands are promising for obtaining Ni (0) complexes with long-lived 3 MLCT states, and this could be interesting for a similar range of applications as with photoactive Cu(I) complexes, including for example luminescent devices, solar cells, and organic photoredox reactions.Keywords metal-to-ligand charge transfer; isocyanide, phosphine; N-heterocyclic carbene; -acceptor; earth-abundant metal element Abbreviations

Photoinduced electron transfer across rigid rod-like oligo-p-phenylenes has been thoroughly investigated in the past, but their o-connected counterparts are yet entirely unexplored in this regard. We report on three molecular dyads comprised of a triarylamine donor and a Ru(bpy) 3 2+ (bpy =2,2′-bipyridine) acceptor connected covalently by 2 to 6 o-phenylene units. Pulsed excitation of the Ru(II) sensitizer at 532 nm leads to the rapid formation of oxidized triarylamine and reduced ruthenium complex via intramolecular electron transfer. The subsequent thermal reverse charge-shift reaction to reinstate the electronic ground-state occurs on a time scale of 120−220 ns in deaerated CH 3 CN at 25 °C. The conformational flexibility of the o-phenylene bridges causes multiexponential transient absorption kinetics for the photoinduced forward process, but the thermal reverse reaction produces single-exponential transient absorption decays. The key finding is that the flexible o-phenylene bridges permit rapid formation of photoproducts storing ca. 1.7 eV of energy with lifetimes on the order of hundreds of nanoseconds, similar to what is possible with rigid rod-like donor−acceptor compounds. Thus, the conformational flexibility of the o-phenylenes represents no disadvantage with regard to the photoproduct lifetimes, and this is relevant in the greater context of light-to-chemical energy conversion.

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After two very successful chemistry symposia held in 2013 and 2014, graduate students from the University of Basel continued this new tradition and held a symposium at the end of the year on Friday, 4 th December 2015. The main topic was dedicated to the UNESCO main theme of 2015: light. The PhD Chemistry Community (PCC)The PCC consists of graduate students and researchers in the Department of Chemistry at the University of Basel. They aim to enhance collaboration and promote community spirit, by organizing social and academic events across the department, such as symposia and research seminars.