Copper Photosensitizers Containing P^N Ligands and Their Influence on Photoactivity and Stability

Abstract

Driven by the intention to improve classic heteroleptic copper photosensitizers two novel Cu(I) complexes applying a hetero-bidentate P^N ligand were prepared. A combined photophysical, electrochemical, and theoretical study gives insights into structure-activity relationships and revealed an increased absorptivity. Both complexes were tested for the light-driven production of H .

Elucidating the Nature of the Excited State of a Heteroleptic Copper Photosensitizer by using Time‐Resolved X‐ray Absorption Spectroscopy

“…The copper centeri sc onsequently less susceptible to nucleophilic attack by solvent molecules and exciplex formation,w hichh ave been knownt ol ead to shorter excited-state lifetimes in their homoleptic counterparts. The fitted CuÀNa nd CuÀPb ond distances are in agreement with the reported single-crystal X-ray diffraction (XRD) structure, [32] and relative trends betweent he relaxed structures from density functional theory (DFT) geometry optimization(Ta ble 1, Table S2 in the Supporting Information). On the other hand, two prominentp eaks are observed for the excited-state derivative corresponding to the distinct contribution of the shortened CuÀNa nd elongatedC u ÀPb onds.…”

Copper(I) Phosphinooxazoline Complexes: Impact of the Ligand Substitution and Steric Demand on the Electrochemical and Photophysical Properties

“…It is also worth noting, that the ligands L4 – L7 possess a chirality center at the 4‐position of the 2‐oxazoline. The synthesis of the ligands L1 , L2 , L5 and L6 was performed following a synthesis procedure from literature, starting from the corresponding and commercially available chiral amino alcohols (see Scheme ). These amino alcohols were first reacted in a Witte–Seeliger reaction to the aryl‐bromide precursor and then converted to the corresponding phox ligands via an Ullman‐type coupling (Scheme ) .…”

“…One possible option to achieve this aim is the replacement of the original P^P ligand by a heterobidentate P^ N ‐ligand . Particularly, the combination of a N ‐heteroaryl moiety, which possesses a wide range of tunable electronic properties and a soft phosphine donor seems promising .…”

“…One possible option to achieve this aim is the replacement of the original P^P ligand by a heterobidentate P^ N ‐ligand . Particularly, the combination of a N ‐heteroaryl moiety, which possesses a wide range of tunable electronic properties and a soft phosphine donor seems promising . Several Cu I complexes based on different types of P^N ligands, mainly as multinuclear cuprous halide complexes, have already been prepared and investigated .…”

“…In a previous study we showed for the first time, that a phosphinooxazoline (phox) based P^N ligand enables stable mononuclear Cu I complexes with interesting photophysical properties . Moreover, also the ability of these complexes to act as photosensitizers for the light‐driven production of H 2 was demonstrated . Hence, the impact of the spatial arrangement and steric demand in such phox ligands on the properties of the resulting Cu I complexes is of high interest.…”