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

Abstract

A series of seven homoleptic CuI complexes based on hetero‐bidentate P^N ligands was synthesized and comprehensively characterized. In order to study structure–property relationships, the type, size, number and configuration of substituents at the phosphinooxazoline (phox) ligands were systematically varied. To this end, a combination of X‐ray diffraction, NMR spectroscopy, steady‐state absorption and emission spectroscopy, time‐resolved emission spectroscopy, quenching experiments and cyclic voltammetry was used to assess the photophysical and electrochemical properties. Furthermore, time‐dependent density functional theory calculations were applied to also analyze the excited state structures and characteristics. Surprisingly, a strong dependency on the chirality of the respective P^N ligand was found, whereas the specific kind and size of the different substituents has only a minor impact on the properties in solution. Most importantly, all complexes except C3 are photostable in solution and show fully reversible redox processes. Sacrificial reductants were applied to demonstrate a successful electron transfer upon light irradiation. These properties render this class of photosensitizers as potential candidates for solar energy conversion issues.

Intertwined Analytical, Experimental and Theoretical Studies on the Formation and Structure of a Copper Dienolate

“…[13] Some papers reported organic phosphines as well as their bidentate derivatives as ligand of copper, but the majority of these studies deal with mixed-ligand complexes, those contain phenylphosphine only as spectator and the cathodic behavior of Cu(I) complexes generally shows a ligand-centered reduction, the Cu(0) formation being not visible. [14] Finally few works concerning copper BINAP complexes are reported, [15] and no on electrochemistry.…”

Towards Optimized Photoluminescent Copper(I) Phenanthroline-Functionalized Complexes: Control of the Photophysics by Symmetry-Breaking and Spin–Orbit Coupling

“…The emissive properties of bis-phenanthroline substituted Cu(I) complexes have been intensively explored starting in the late 70s [ 1 , 2 , 3 , 4 ] because of intriguing luminescence properties extremely sensitive to structural effects driven by the surrounding ligands [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. The development of time-resolved spectroscopies and pump–probe X-ray experiments has allowed the mapping of ultrafast kinetics that precede the formation of potentially long-lived triplet T 1 excited states [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. The decay mechanism involves several intermediate singlet and triplet excited states coupled vibronically and by spin–orbit [ 44 , 45 , 46 , 47 , …”

Tuning the architectures and luminescence properties of Cu(i) compounds of phenyl and carboranyl pyrazoles: the impact of 2D versus 3D aromatic moieties in the ligand backbone

“…Polynuclear copper(I) halide clusters have been widely investigated over decades due to their intriguing photophysical properties. [1][2][3][4][5][6][7][8][9][10] Potential applications for these materials include light-emitting devices (OLEDs), [11][12][13] light-emitting electrochemical cells (LECs), 14 solar cells 15 and luminescent sensors. 16,17 The interest in this family of compounds does not only stems from their photoluminescent properties, but also from the great diversity of structural motifs of the Cu x X y L z (X = Cl, Br, I) skeleton.…”