Heteroleptic Copper(I) Complexes Coupled with Methano[60]fullerene: Synthesis, Electrochemistry, and Photophysics

Abstract

Heteroleptic copper(I) complexes CuPOP-F and CuFc-F have been prepared from a fullerene-substituted phenanthroline ligand and bis[2-(diphenylphosphino)phenyl] ether (POP) and 1,1'-bis(diphenylphosphino)ferrocene (dppFc), respectively. Electrochemical studies indicate that some ground-state electronic interaction between the fullerene subunit and the metal-complexed moiety are present in both CuPOP-F and CuFc-F. Their photophysical properties have been investigated by steady state and time-resolved UV-vis-NIR luminescence spectroscopy and nanosecond laser flash photolysis in a CH2Cl2 solution and compared to those of the corresponding model copper(I) complexes CuPOP and CuFc and of the fullerene model compound F. Selective excitation of the methanofullerene moiety in CuPOP-F results in regular deactivation of the lowest singlet and triplet states, indicating no intercomponent interactions. Conversely, excitation of the copper(I)-complexed unit (405 nm, 40% selectivity) shows that the strongly luminescent triplet metal-to-ligand charge-transfer ((3)MLCT) excited state located at 2.40 eV is quenched by the carbon sphere with a rate constant of 1.6 x 10(8) s(-1). Details on the mechanism of photodynamic processes in CuPOP-F via transient absorption are hampered by the rather unfavorable partition of light excitation between the two chromophores. By determination of the yield of formation of the lowest fullerene triplet level through sensitized singlet oxygen luminescence in the NIR region, it is shown that the final sink of photoinduced processes is always the fullerene triplet. This can be populated via a two-step charge-separation charge-recombination process and a less favored (3)MLCT --> (3)C60 triplet-triplet energy-transfer pathway. In CuFc-F, both of the photoexcited copper(I)-complexed and fullerene moieties are quenched by the presence of the ferrocene unit, most likely via ultrafast energy transfer.

Takotsubo cardiomyopathy and microvascular dysfunction: Another diagnostic criteria or predisposing factor?

“…It is proved that the metallic d electrons are transferred to fullerene cages, resulting in richer electron density inside the carbon cage. Although C 60 may act as an electron acceptor in the fullerene derivatives,[45–48] we find for the first time that the metal donates its d electrons to two fullerene cages resulting into a more extended conjugate molecule Pt(C 60 ) 2 . The deformation charge density maps of C 2 (C 60 ) 2 and Pt(C 60 ) 2 have also been examined and shown in Figure 5.…”

Syntheses, Structures, and Photoluminescence Properties of a Series of 3D Zn‐Ln Heterometallic Complexes with 2,3‐Pyrazine Dicarboxylic Acid as a Bridging Ligand

“…Although the valence electron configuration of the d 10 elements is different from that of the non d 10 elements with a typical d–d transition, it has other advantages. The d‐block chromophores with d 10 valence electron configuration not only have a flexible coordination number that can form a variety of arrangements, but also have a lower triplet excited state level, which can have a better match with the excited state energy grade of Ln III , and it can sensitize the luminescence of the f block more efficiently , . In recent years, the synthesis of luminescent lanthanide complexes of Zn II and Cd II has developed rapidly , .…”

Versatile Bisethynyl[60]fulleropyrrolidine Scaffolds for Mimicking Artificial Light‐Harvesting Photoreaction Centers

“…[6,7] In particular, their use in donor-acceptor systems for photovoltaic devices has impressively expanded. [8,9] To this end, a variety of [60]fullerene derivatives linked to electron-donating units such as, among others, porphyrins, [10][11][12][13][14] tetrathiafulvalenes (TTFs), [15] ferrocene, [16] phthalocyanines, [17] oligophenylenevinylenes, [18] and transition-metal complexes [19][20][21] have been prepared. The mechanisms of photoinduced electron and energy transfer have been elucidated by means of timeresolved spectroscopic methods, thus showing a strong intramolecular quenching of the excited singlet and triplet states of C 60 through the formation of charge-separated (CS) radical ion pairs.…”