An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Iridium(III) and ruthenium(II) polypyridyl based photocatalysts have been prepared and their structure determined using 1 H NMR, HR‐MS and single crystal XRD. Their spectroscopic and electrochemical properties have been studied by UV‐vis absorption, emission spectroscopy and cyclic voltammetry. These complexes have been used as photoredox homogeneous catalysts in an intramolecular cyclization model reaction in which they show high activity. They have been covalently anchored on graphene oxide (GO) via an esterification reaction and non‐covalently fixed on reduced graphene oxide (rGO) via pyrene moieties. Heterogenized complexes exhibit good photocatalytic activities and, interestingly, the use of a pyrene‐derivatized Ir(III) terpyridine‐based complex highlights an unexpected “on/off” effect of the photocatalytic activity triggered by the presence or absence of rGO.

Two bis-terdentate cyclometalated Ir(III) complexes with polypyridyl (N^N^N) and cyclometalated (C^N^C) ligands [Ir-Py]+ and [Ir-Py-Me]2+ have been synthesized and characterized. Their absorption and emission properties have been examined, more particularly in MeCN as a function of the addition of different acids. Depending on the acid strength and concentration, two distinct effects have been observed. For acetic acid at high concentration or trifluoroacetic acid (TFA) at low concentration, the pyridine moiety of [Ir-Py]+ is protonated; its spectroscopic behaviour is then similar to that of [Ir-Py-Me]2+. Moreover at higher concentration in TFA, the methoxy group of both complexes is protonated. The spectroscopic and electrochemical data as well as the DFT and TD-DFT calculations support contributions of charge-transfer excited states in absorption and emission from metal-ligand/ligand based HOMOs to ligand-based LUMOs, i.e. MLLCT.

A bis-cyclometaling ligand afforded a novel IrIII–CoIII dinuclear complex with vectorial electron transfer that evolved hydrogen gas upon yellow-light irradiation. The supramolecular photosystem provided increased stability during photocatalysis with respect to that of classic bidentate systems.

A one-pot synthesis of substituted multi-2,2':6',2″-terpyridines (multi-tpy) has been achieved using an acetylquaterpyridine precursor with various aryl aldehydes in basic media. This strategy enables ready access to functionalized tri-terpyridines. Utilizing a Suzuki-type cross-coupling, larger structures such as tetra- or even hexa-tpy were obtained from our tri-tpy precursor. These macromolecular units are ideal building blocks for the construction of transition-metal-based supramolecular assemblies.

Two bis-terdentate iridium(III) complexes with polypyridyl and cyclometalated ligands have been prepared and characterized. Their spectroscopic and electrochemical properties have been studied, and a photophysical scheme addressing their properties is proposed. Different types of excited states have been considered to account for the deactivation processes in each complex. Interestingly, in the presence of mono- or polynucleotides, a photoinduced electron-transfer process from a DNA purine base (i.e., guanine or adenine) to the excited complex is shown through luminescence quenching experiments. For the first time, this work reports evidence for selective DNA purine bases oxidation by excited iridium(III) bis-terdentate complexes.