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Cobalt metallocycles

1984; Elsevier BV; Volume: 272; Issue: 2 Linguagem: Inglês

10.1016/0022-328x(84)80469-6

1872-8561

Hiroshi Yamazaki, Yasuo Wakatsuki,

Synthetic Organic Chemistry Methods

(η-Cyclopentadienyl)(triphenylphosphine)cobaltacyclopentadienes having an electron withdrawing substituent on the cyclopentadienyl ring, (η-C5H4R)(PPh3)(CoCHCHCH) (1b: R = COOMe; 1c: R = COMe), were prepared in reasonable yields by treatment of a solution of (η-C5H4R)(PPh3)2Co with acetylene. A non-substituted cyclopentadienyl analog (1a: R = H) was also isolated in low yield according to a similar procedure. Novel dinuclear complexes were also formed as by-products and the structure of (η-C5H4R)Co(PPh2C6H4)(μ-CMe)Co(η-C5H4R) (2b: R = COOMe), having a μ2,η3-benzyl moiety, was determined by an X-ray crystallographic analysis. The X-ray analyses of 1a and 1b were also carried out. Crystals of 1a are monoclinic, space group Pa, a 8.529(3), b 16.010(6), c 8.028(4) Å, β 100.31(3)°, Z = 2; crystals of 1b are monoclinic, space group P21/a, a 8.327(2), b 36.468(7), c 8.021(1) Å, β 98.75(2)°, Z = 4; and crystals of 2b are monoclinic, space group P21/c, a 10.681(2), b 30.722(7), c 8.912(1) Å, β 93.55(1)°, Z = 4. They have been refined to R = 0.034, 0.047 and 0.050, respectively.