Quadruply Bonded Complexes Containing Bridging Acetate and η 3 -Phosphine Ligands. Synthesis and Structural Characterization of Mo 2 (OAc)Cl 3 (η 3 -tetraphos-2) and Mo 2 (OAc)Cl 3 (η 3 -etp) (tetraphos-2 = P(CH 2 CH 2 PPh 2 ) 3 ; etp = Ph 2 PCH 2 CH 2 P(Ph)CH 2 CH 2 PPh 2 )
1996; American Chemical Society; Volume: 35; Issue: 10 Linguagem: Inglês
10.1021/ic951187b
ISSN1520-510X
AutoresChang-Tai Lee, Shih‐Fu Chiang, Chun‐Ting Chen, Jhy‐Der Chen, Chwan‐Deng Hsiao,
Tópico(s)Asymmetric Hydrogenation and Catalysis
ResumoThe complexes Mo2(OAc)Cl3(η3-tetraphos-2) (tetraphos-2 = P(CH2CH2PPh2)3, 1, and Mo2(OAc)Cl3(η3-etp)(etp = Ph2PCH2CH2P(Ph)CH2CH2PPh2), 2, were prepared by reactions of Mo2(OAc)2Cl2(PPh3)2 with tetraphos-2 and etp, respectively, in CH2Cl2. Their UV−vis and 31P-NMR spectra have been recorded and their structures have been determined. Crystal data for 1: space group Pbca, a = 24.450 (2) Å, b = 27.486 (3) Å, c = 15.017 (3) Å, V = 10091 (2) Å3, and Z = 8, with final residuals R = 0.0683 and Rw = 0.0724. Both the tetraphos-2 and etp ligands coordinate to the Mo centers in tridentate fashions with chelating/bridging bonding modes. The complexes that are also bridged by the acetate ligands are twisted about the metal−metal bonds with average twist angles of 13.2° for 1 and 11.4° for 2, respectively. The lowest energy bands at 643 nm (14 389 cm-1, ε = 909 M-1 cm-1) for 1 and 644 nm (14388 cm-1, ε = 1536 M-1 cm-1) for 2 can be assigned to δ → δ * transitions. The study on 31P{1H} NMR spectra of 1 and 2 concluded that the through metal−metal quadruple bonding coupling |3JP-Mo-Mo-P| is about 20 ± 1 Hz.
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