Heteroleptic Ter–Bidentate Cr(III) Complexes as Tunable Optical Sensitizers

Article Article scientifique Article Heteroleptic Ter–Bidentate Cr(III) Complexes as Tunable Optical Sensitizers eng 2018 author Doistau Benjamin 837090 author Collet Guillaume 861825 author Acuna Bolomey Emilio 801492 author Sadat-Noorbakhsh Vida 774395 author Besnard Céline 682138 author Piguet Claude 0000-0001-7064-8548 22415 14362-14373 10.1021/acs.inorgchem.8b02530 0020-1669 In order to exploit Cr(III) coordination complexes as sensitizers in supramolecular energy-converting devices, the latter optical relays should display long-lived excited states, broad emission bands and tunable spatial and electronic connections to activator units. An ad-hoc versatile strategy has been therefore developed for the preparation of a family of luminescent pseudo-octahedral [CrN6] chromophores made up of ter-bidentate heteroleptic [Cr(phen)2(N-N')]3+ complexes, where phen is 1,10-phenanthroline and N-N' stands for ,'-diimine ligands possessing peripheral substituents compatible with both electronic tuning and structure extensions. As long as the ligand field in these [CrN6] chromophores remains sufficiently strong to avoid back intersystem crossing, photophysical studies indicate that the lifetime of the near-infrared emissive Cr(2E) excited state is poorly sensitive to 2 ligand-based electronic effects. On the contrary, a drop in symmetry, the coupling with high frequency oscillators and the implementation of sterical constraints in heteroleptic [Cr(phen)2(N-N')]3+ complexes affect both Cr(2E4A2) energies and Cr(2E) lifetimes. Altogether, [Cr(phen)2(phenAlkyn)]3+ (phenAlkyn = 5-ethynyl-1,10-phenanthroline) and [Cr(phen)2(dpma)]3+ (dpma = di(pyrid-2- yl)(methyl)amine) complexes mirror the favorable photophysical properties of homoleptic [Cr(phen)3]3+ and thus emerge as the best heteroleptic candidates for acting as sensitizers at room temperature, and below 100 K, respectively, in more complicated architectures. Chromium(III) Complex Heteroleptic Lifetime Sensitizer Symmetry Dewey 540 Swiss National Science Foundation Can Functional Metallopolymers and Supramolecular Assemblies Benefit from Molecular Organization Mastered by Coordination Chemists ? 178758 CH Project funding 40 Département de chimie minérale, analytique et appliquée 145 false 774 Groupe Piguet Inorganic Chemistry 57 22 71f8e8cb-b322-4d64-a42a-de2b24fc773b Article (Accepted version) Public Cr(Phen)2L_text_Revision.pdf 893890 application/pdf openAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

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Heteroleptic Ter–Bidentate Cr(III) Complexes as Tunable Optical Sensitizers	Inorganic Chemistry			2018	578	1,918

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Acuna Bolomey, Emilio