Discovery of (9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine)

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161265-03-8. Let¡¯s face it, organic chemistry can seem difficult to learn. Especially from a beginner¡¯s point of view. Like 161265-03-8, Name is (9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine). In a document type is Article, introducing its new discovery.

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts to Produce H2

The synthesis of two new heteroleptic Cu(I) photosensitizers (PS), [Cu(Xantphos)(NN)]PF6 (NN = biq = 2,2?-biquinoline, dmebiq = 2,2?-biquinoline-4,4?-dimethyl ester; Xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene), along with the associated structural, photophysical, and electrochemical properties, are described. The biquinoline diimine ligand extends the PS light absorbing properties into the visible with a maximum absorption at 455 and 505 nm for NN = biq and dmebiq, respectively, in CH2Cl2 solvent. Following photoexcitation, both Cu(I) PS are emissive at low energy, albeit displaying stark differences in their excited state lifetimes (MLCT = 410 ¡À 5 (biq) and 44 ¡À 4 ns (dmebiq)). Cyclic voltammetry indicates a Cu-based HOMO and NN-based LUMO for both complexes, whereby the methyl ester substituents stabilize the LUMO within [Cu(Xantphos)(dmebiq)]+ by -0.37 V compared to the unsubstituted analogue. When combined with H2O, N,N-dimethylaniline (DMA) electron donor, and cis-[Rh(NN)2Cl2]PF6 (NN = Me2bpy = 4,4?-dimethyl-2,2?-bipyridine, bpy = 2,2?-bipyridine, dmebpy = 2,2?-bipyridine-4,4?-dimethyl ester) water reduction catalysts (WRC), photocatalytic H2 evolution is only observed using the [Cu(Xantphos)(biq)]+ PS. Furthermore, the choice of cis-[Rh(NN)2Cl2]+ WRC strongly affects the catalytic activity with turnover numbers (TONRh = mol H2 per mol Rh catalyst) of 25 ¡À 3, 22 ¡À 1, and 43 ¡À 3 for NN = Me2bpy, bpy, and dmebpy, respectively. This work illustrates how ligand modification to carefully tune the PS light absorbing, excited state, and redox-active properties, along with the WRC redox potentials, can have a profound impact on the photoinduced intermolecular electron transfer between components and the subsequent catalytic activity.

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Reference£º
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate