Chemie polyfunktioneller Moleküle, 106. Kupfer(I)halogenid — Komplexe des Bis(diphenylphosphino)amins / Chemistry of Polyfunctional Molecules, 106. Copper(I) Halide Complexes of Bis(diphenylphosphino)amine

Abstract

Reaction of Copper(I) halides CuX (X = Cl, Br, I) in methanol with bis(diphenylphosphino)amine (dppa, 1) yields complexes [Cu3X2(dppa)3]X (X = Cl, Br, I: 2a–c). The derivates [Cu3X2(dppa)3]PF6 (2a′–c′) have been synthesized by metatheses of 2a–c with NH4PF6. The IR, Raman, 31P{1H} NMR, 1H{31Ρ} NMR, 13C{1H} NMR spectra, and FD mass spectra as well as the conductivity data are reported and discussed together with the X-ray crystal structure of 2a · 5 CH3OH. The structure consists of the trinuclear cations [Cu3Cl2(dppa)3]+, distorted tetrahedral anions [Cl( · · · HOCH3)4]- and molecules of methanol of crystallization, hydrogen bridged to the solvated anions. The Cu3Cl2 core of the cations corresponds closely to a trigonal bipyramid with the copper atoms in the equatorial and the chlorine atoms in the axial positions. The colourless prisms of 2a · 5 CH3OH crystallize in the triclinic space group P1̅, with the lattice constants a = 1368.0(4); b = 1486.7(4); c = 2036.8(10) pm; α = 74.52(3); β = 74.73(3); γ = 82.26(2)°. Raman and 31P{1H} NMR data of the complexes [Cu(X)dppm]4 (dppm = (C6H5)2PCH2P(C6H5)2; X = Br, I) described earlier suggest that these compounds should also be formulated as [Cu3X2(dppm)3]X (4b, c).The Raman spectra of the cations of 2a–c, 2a′–c′ and 4a–c show bands at 165 (X = Cl), 145 (X = Br) and 125 (X = I) cm-1, which can be assigned to the symmetric (XCu3X) stretching mode of the XCu3X unit.

Chelating and bridging diphosphinoamine (PPh2)2N(iPr) complexes of copper(I)

“…Similar trimeric structures are known with dppm [bis(diphenylphosphino)methane] [20] and dppa [bis(diphenylphosphino)amine] [21] with average Cu-Cu distance of 3.210(4) Å and 2.989(2) Å, respectively. The Cu-Cl distances varied from 2.407(7) Å to 2.678(6) Å in the former and range from 2.426(2) Å to 2.487(3) Å in the latter.…”

Catalytic cyclopropanation of olefins using copper(I) diphosphinoamines

“…(Table 8) Tetrakis(acetonitrile)copper(I) with different counter anions namely perchlorate and tetrafluoroborate were also investigated under similar conditions. Cyclopropanation reactions with the corresponding hexafluorophosphate complex has been reported [19]. Reactions with 0.5 mol% of tetrakis(acetonitrile)copper(I) perchlorate and tetrafluoroborate and 10 equivalents of styrene in CDCl 3 under the optimized reaction conditions discussed earlier (entry 1 and entry 2) gave about 88% and 90% of the cyclopropane in 4 h and 1 h, respectively.…”

“…The catalytic cyclopropanation was attempted with the perchlorate complex [Cu 2 (dppa) 2 (CH 3 CN)(OH 2 )(OClO 3 ]ClO 4 and the halide complexes of dppa, [Cu 3 (dppa) 3 X 2 ]X (X = Cl, Br) previously reported by Ellermann et al [19]. The results of the catalytic reactions are shown in Table 4.…”

“…This simple model is able to explain most of the observations made in this study. Thus copper(I) triflate [21] and hexafluorophosphates [19] complexes are highly reactive compared to the chloride complexes [21b].…”

Chelating and bridging bis(diphenylphosphino)aniline complexes of copper(I)

“…The role of halide bridges in tuning the Cu-Cu distances has been elegantly demonstrated in a recent paper by Knight et al [25]. Obviously, the copper-copper distances are affected by both ligands and this is amply illustrated by the work of Ellermann et al [26] and Bera et al [27]. It has also been shown that shorter distances can arise when there is unsymmetric coordination [28].…”