Easy Access to the Copper(III) Anion [Cu(CF₃)₄]⁻

Abstract

CuCl or pre-generated CuCF3 reacts with CF3 SiMe3 /KF in DMF in air to give [Cu(CF3 )4 ](-) quantitatively. [PPN](+) , [Me4 N](+) , [Bu4 N](+) , [PhCH2 NEt3 ](+) , and [Ph4 P](+) salts of [Cu(CF3 )4 ](-) were prepared and isolated spectroscopically and analytically pure in 82-99% yield. X-ray structures of the [PPN](+) , [Me4 N](+) , [Bu4 N](+) , and [Ph4 P](+) salts were determined. A new synthetic strategy with [Cu(CF3 )4 ](-) was demonstrated, involving the removal of one CF3 (-) from the Cu atom in the presence of an incoming ligand. A novel Cu(III) complex [(bpy)Cu(CF3 )3 ] was thus prepared and fully characterized, including by single-crystal X-ray diffraction. The bpy complex is highly fluxional in solution, the barrier to degenerate isomerization being only 2.3 kcal mol(-1) . An NPA study reveals a huge difference in the charge on the Cu atom in [Cu(CR3 )4 ](-) for R=F (+0.19) and R=H (+0.46), suggesting a higher electron density on Cu in the fluorinated complex.

Copper‐Mediated Trifluoromethylation of Benzylic Csp3−H Bonds

“…Despite the fact that stoichiometric amounts of 1 are used in this reaction, its synthesis can be easily scaled up. Although previous methods for the synthesis of 1 required either large excess of TMSCF 3 or tedious column chromatography purification, we found that it can be synthesized from a one‐step procedure and purified by crystallization in CH 2 Cl 2 . This allowed us to synthesize 1 in a large scale without column chromatography (Figure a).…”

Homoleptic Trifluoromethyl Derivatives of AgI and AgIII

“…It is also appreciably longer than the Cu−C bond distance in [PPh 4 ][Cu(CF 3 ) 4 ] (195.1(3) pm av. ), but indistinguishable within the experimental error from the Au−C bond length in [NBu 4 ][Au(CF 3 ) 4 ] (208.0(7) pm av.) .…”

Electronic Structure of Copper Corroles

“…Simulations for these spectra are presented in Figure S6 and the parameters are summarised in Table S2. X-ray photoelectron spectroscopy (XPS) is particularly diagnostic of the oxidation state in copper complexes,a s shake-up satellite peaks are observed in the Cu 2p region of the spectrum for Cu II species,b ut are absent for Cu III derivatives. [24,25] Figure 4d shows the XPS spectra of the Cu corroles as compared to Cu-2 and [TBA][Cu(CF 3 ) 4 ], [26] which were studied as authentic Cu II To complement spectroscopic experiments,D FT calculations (B3LYP/6-311G(d,p) with toluene CPCM solvation) were performed for Cu-1 as ac losed shell 1 Cu(III) singlet, af erromagnetically coupled 3 Cu(II) corrole radical cation, and an antiferromagnetically coupled, broken symmetry 1 Cu(II) corrole radical cation (Tables S3-S5, Figure S7 and S8). TheB 3LYP functional has been used to study aw ide variety of copper complexes [28] and it has been shown for copper corroles to give the most accurate values of DE T-S when benchmarked against pure functionals or multiconfigurational methods.…”