Synthesis, Structure, and Luminescence of Copper(I) Halide Complexes of Chiral Bis(phosphines)

Abstract

For investigation of structure-property relationships in copper phosphine halide complexes, treatment of copper(I) halides with chiral bis(phosphines) gave dinuclear [Cu((R,R)-i-Pr-DuPhos)(μ-X)] [X = I (1), Br (2), Cl (3)], [Cu(μ-((R,R)-Me-FerroLANE)(μ-I)] (5), and [Cu((S,S)-Et-FerroTANE)(I)] (6), pentanuclear cluster CuI((S,S)-Et-FerroTANE) (7), and the monomeric Josiphos complexes Cu((R,S)-CyPF-t-Bu)(I) (8) and Cu((R,S)-PPF-t-Bu)(I) (9); 1-3, 5, and 7-9 were structurally characterized by X-ray crystallography. Treatment of iodide 1 with AgF gave [Cu((R,R)-i-Pr-DuPhos)(μ-F)] (4). DuPhos complexes 1-4 emitted yellow-green light upon UV irradiation at room temperature in the solid state. This process was studied by low-temperature emission spectroscopy and density functional theory (DFT) calculations, which assigned the luminescence to (M + X)LCT (CuX to DuPhos aryl) excited states. Including Grimme's dispersion corrections in the DFT calculations (B3LYP-D3) gave significantly shorter Cu-Cu distances than those obtained using B3LYP, with the nondispersion-corrected calculations better matching the crystallographic data; other intramolecular metrics are better reproduced using B3LYP-D3. A discussion of the factors leading to this unusual observation is presented.

Bulky 1,1′-bisphosphanoferrocenes and their coordination behaviour towards Cu(i)

“…The complexation via the formation of Cu 2 X 2 (X = Cl, Br, I) bridges is common for dppf 51,[92][93][94][95][96] and some sterically encumbered dppf analogues. 90,[97][98][99] However, apart from this rare bonding motif, the classical chelating coordination mode of a single metal centre is also known for them. 25,90,100 For the [Mes 2 P]-substituted ferrocene ligands, the formation of Cu 2 X 2 bridges seems to be favoured as non-chelating ligand 4 similarly results in this motif for complex 14, which was synthesized by reacting 4 with one equivalent of CuBr.…”

Structural characterization and luminescence properties of trigonal Cu(i) iodine/bromine complexes comprising cation–π interactions

“…Meanwhile, the PLQY value progression ( 1 < 2 ) is also rarely observed in luminescent Cu( i ) halide derivatives as heavier halides usually promote efficient radiative relaxation processes via external heavy-atom effects. 52 The aforementioned crystal data analysis reveals that the Cu–π imidazole interaction in 1 is stronger than that of 2 , which could facilitate MLCT transition in excited states and thus lead to a slight decrease in energy emission and PLQY. Consequently, the solid-state luminescence behaviours of 1 and 2 could be ascribed to the combined effects of Cu–π interactions and heavy atoms, which offers the possibility of a novel design strategy for luminescent materials with interesting structures with superior performance.…”

Catalytic Asymmetric Synthesis of P-Stereogenic Phosphines: Beyond Precious Metals

“…Bypassing the challenging synthesis of C 3 -symmetric tridentate ligands, Sarah Gibbons used commercially available C 2 -and C 1 -symmetric bis(phosphines) to reinvestigate Cu-catalyzed asymmetric phosphine alkylation, as in Scheme 5. She first prepared two types of catalyst precursors, the neutral halide complexes 46 [Cu(diphos*)(X)] n and cations such as [Cu(i-Pr-Du-Phos)(PHMe(Is))][PF 6 ], which contained labile secondary phosphines. 29 As in the Cu(IPr) system, deprotonation of the cations with our favorite base, NaOSiMe 3 , resulted in proton-transfer equilibria between copper-silanolate and copper-phosphido complexes, silanol, and secondary phosphine, again highlighting the downside of using harder first-row metals.…”