Acta Chim. Sinica ›› 2017, Vol. 75 ›› Issue (1): 92-98.DOI: 10.6023/A16070364 Previous Articles     Next Articles

Special Issue: 有机光化学


基于偶氮桥连的新型双铁羰基配合物:Fe2(N2C5H10)(CO)6-x (PR3)x的合成及衍生

李冉, 徐文元, 赵巾钦, 余鑫, 王文光, 佟振合   

  1. 山东大学化学与化工学院 济南 250100
  • 投稿日期:2016-07-27 修回日期:2016-10-11 发布日期:2016-10-20
  • 通讯作者: 王文光,
  • 基金资助:


Azo-bridged New Diiron Carbonyl Complex: Synthesis of Fe2(NR)2-(CO)6-x(PR3)x and the Derivatives

Li Ran, Xu Wenyuan, Zhao Jinqin, Yu Xin, Wang Wenguang, Tung Chen-Ho   

  1. Department of Chemistry & Chemical Engineering, Shandong University, Jinan 250100, China
  • Received:2016-07-27 Revised:2016-10-11 Published:2016-10-20
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21402107, 91427303), the financial support from the "1000 Youth Talents Plan" and National Undergraduate Training Programs for Innovation and Entrepreneurship (No. 201510422032).

Heating the toluene solution of 4,4-dimethyl-4,5-dihydro-3H-pyrazole (N2C5H10) and Fe3(CO)12 at reflux for 1 h produces diiron hexacarbonyls Fe2(N2C5H10)(CO)6 (1, νCO(CH2Cl2):2069, 2022, 1986 cm-1). Compound 1 exhibits 34 e- configuration, in which (N2C5H10)2- coordinates to diiron (FeIFeI) centers featuring a butterfly structure. To a solution of 1 in toluene was added one equiv. of decarbonyl agent Me3NO in MeCN, and the mixture was stirred at room temperature for 20 min. Then, one equiv. of monophosphine was added. After 3 h, the solvent was removed and the residue was extracted into 5 mL CH2Cl2. The product Fe2(N2C5H10)(CO)5(PR3) (PR3=PPh3, 2a; PCy3, 2b) was obtained as brown crystals by allowing a pentane layer to diffuse into the CH2Cl2 solution at -20℃. 31P NMR spectra exhibit a singlet at δ 67 for 2a and δ 70 for 2b in CH2Cl2, respectively. In IR spectra, the νCO bands for 2a were displayed at 2032, 1968, 1952, 1907 cm-1, which are compared to 2024, 1959, 1937, 1893 cm-1 for 2b. Photolysis the toluene solution of 1 in the presence of chelating diphosphine ligands such as dppe[dppe=1,2-C2H4(PPh2)2] and dppbz[dppbz=1,2-C6H4(PPh2)2] affords diiron diphosphine carbonyl compounds. For dppe, the product was Fe2(N2C5H10)(CO)4(μ-dppe) (3a, 31P NMR (CD2Cl2):δ 95, FT-IR (CH2Cl2, νCO):1984, 1940, 1925 and 1900 cm-1), in which dppe is bridging the two iron centers. For more rigid diphosphine ligand dppbz, X-ray crystallographic analysis reveals the structure of Fe2(N2C5H10)(μ-CO)(CO)4(dppbz)[3b, 31P NMR (CD2Cl2):δ 93]. In 3b, (N2C5H10)2- coordinates to diiron centers in a planar mode, and dppbz chelates at one Fe site by the replacement of one CO ligand. Compound 3b features a Fe-CO-Fe rotated structure with a bridging CO ligand between the two Fe centers. The νCO bands for 3b were displayed at 1990, 1947, 1919, 1895 cm-1. With such a rotated structure, compound 3b provides a new approach for synthetic models of Hred state of [FeFe]-H2ase. The CCDC number for 1, 2a, 2b, 3a and 3b are 1494954, 1494955, 1494956, 1494966 and 1494957. All the compounds were well characterized by NMR, IR spectroscopy and elemental analysis.

Key words: [FeFe] hydrogenase, diiron carbonyls, phosphine ligands, rotated structure, bridging CO ligand