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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.

Quinolinium salt 3 is an effective additive that acts as a conformation control element (CCE) to promote macrocyclization to form rigid cyclophanes via olefin metathesis or Glaser-Hay coupling, which do not cyclize in the absence of the additive. The additives are easily synthesized and highly modifiable and have solubility profiles which allow for simple recovery via filtration.

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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.

Iridium(III) and ruthenium(II) polypyridyl based photocatalysts have been prepared and their structure determined using 1H 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.

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