Electrophilic attack of H+ and [Au(PPh3)]+ on an electron-rich rhodium-rhodium bond. Synthesis and structural characterization of [Rh2(η-C5H5) 2(μ-CO)(μ-H)(μ-Ph2PCH2PPh 2)]+ and [Rh2(η-C5H5) 2(μ-CO)(μ-AuPPh3)(μ-Ph2PCH 2PPh2)]+. The synthesis of compounds [Rh2(η-C5H5) 2(μ-CO)(μ-H)(μ-dppm)]X (2a, X = BF4; 2b, X = PF6) and [Rh2(η-C5H5) 2(μ-CO)(μ-AuPPh3)(μ-dppm)]X (3a, X = BF4; 3b, X = PF6) (dppm = Ph2PCH2PPh2), via the addition of H+ and [AuPPh3]+ to the electron-rich metal-metal bond of the complex [Rh2(η-C5H5) 2(μ-CO)(μ-dppm)] (1), is described. Crystals of 2a are orthorhombic of space group Pbca with a = 11.399 (1) Å, b = 17.991 (2) Å, c = 32.819 (4) Å, and Z = 8. The structure was solved and refined to R and Rw values of 0.061 and 0.064 for the 2046 reflections with I ≥ 3σ(I). The hydride ligand bridges the Rh-Rh bond [2.721 (2) Å] with Rh(1)-H and Rh(2)-H distances [1.62 (14) and 1.71 (14) Å, respectively] which do not differ significantly. The metals are also bridged by the dppm and CO ligands. Complex 3a crystallizes in the space group P212121 with a = 26.589 (3) Å, b = 16.080 (2) Å, c = 11.710 (1) Å, and Z = 4. The structure has been refined to R = 0.037 and Rw = 0.042 for the 3066 reflections with I ≥ 3σ(I). The basic trinuclear skeleton consists of an almost equilateral triangle formed by the two rhodium atoms and the gold atom [Rh(1)-Rh(2) = 2.760 (2) Å, Rh(1)-Au = 2.718 (1) Å, and Rh(2)-Au = 2.732 (1) Å] with the Rh-Rh bond bridged by the dppm and the carbonyl ligands. The structural features of the bridging dppm and CO groups in 2a and 3a remain essentially the same as in 1; the two cyclopentadienyl ligands are in the cis position with an interplanar angle of 92.7° in 2a and 93.9° in 3a. The structural modification of 1 caused by the presence of the bridging hydride and AuPPh3 groups is discussed. Spectroscopic IR and 1H and 31P NMR data for the new compounds are presented.

Electrophilic attack of proton and [Au(PPh3)]+ on an electron-rich rhodium-rhodium bond. Synthesis and structural characterization of [Rh2(η-C5H5)2(μ-CO)(μ-H)(μ-Ph2PCH2PPh2)]+ and [Rh2(η-C5H5)2(μ-CO)(μ-AuPPh3)(μ-Ph2PCH2PPh2)]+

LO SCHIAVO, Sandra;BRUNO, Giuseppe;NICOLO', Francesco;PIRAINO, Pasquale;FARAONE, Felice
1985-01-01

Abstract

Electrophilic attack of H+ and [Au(PPh3)]+ on an electron-rich rhodium-rhodium bond. Synthesis and structural characterization of [Rh2(η-C5H5) 2(μ-CO)(μ-H)(μ-Ph2PCH2PPh 2)]+ and [Rh2(η-C5H5) 2(μ-CO)(μ-AuPPh3)(μ-Ph2PCH 2PPh2)]+. The synthesis of compounds [Rh2(η-C5H5) 2(μ-CO)(μ-H)(μ-dppm)]X (2a, X = BF4; 2b, X = PF6) and [Rh2(η-C5H5) 2(μ-CO)(μ-AuPPh3)(μ-dppm)]X (3a, X = BF4; 3b, X = PF6) (dppm = Ph2PCH2PPh2), via the addition of H+ and [AuPPh3]+ to the electron-rich metal-metal bond of the complex [Rh2(η-C5H5) 2(μ-CO)(μ-dppm)] (1), is described. Crystals of 2a are orthorhombic of space group Pbca with a = 11.399 (1) Å, b = 17.991 (2) Å, c = 32.819 (4) Å, and Z = 8. The structure was solved and refined to R and Rw values of 0.061 and 0.064 for the 2046 reflections with I ≥ 3σ(I). The hydride ligand bridges the Rh-Rh bond [2.721 (2) Å] with Rh(1)-H and Rh(2)-H distances [1.62 (14) and 1.71 (14) Å, respectively] which do not differ significantly. The metals are also bridged by the dppm and CO ligands. Complex 3a crystallizes in the space group P212121 with a = 26.589 (3) Å, b = 16.080 (2) Å, c = 11.710 (1) Å, and Z = 4. The structure has been refined to R = 0.037 and Rw = 0.042 for the 3066 reflections with I ≥ 3σ(I). The basic trinuclear skeleton consists of an almost equilateral triangle formed by the two rhodium atoms and the gold atom [Rh(1)-Rh(2) = 2.760 (2) Å, Rh(1)-Au = 2.718 (1) Å, and Rh(2)-Au = 2.732 (1) Å] with the Rh-Rh bond bridged by the dppm and the carbonyl ligands. The structural features of the bridging dppm and CO groups in 2a and 3a remain essentially the same as in 1; the two cyclopentadienyl ligands are in the cis position with an interplanar angle of 92.7° in 2a and 93.9° in 3a. The structural modification of 1 caused by the presence of the bridging hydride and AuPPh3 groups is discussed. Spectroscopic IR and 1H and 31P NMR data for the new compounds are presented.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/2036444
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