Cobalt complexes with bulky perfluorinated alkyl ligands. Synthesis, characterization, and molecular structure of trans-bis(dimethylglyoximato)(pyridine)(F-isopropyl)cobalt(III)

Paul J. Toscano, Holger Brand, Shuncheng Liu, Jon A Zubieta

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Abstract

The preparation of pyCo(DH)2[CF(CF3)2] (1) from Na[pyCo(DH)2] and (CF3)2CFI is described, where py = pyridine and DH = the monoanion of dimethylglyoxime. The Co(I) anion reagent is prepared from pyCo(DH)2Cl and 0.25 molar equiv of NaBH4. Larger proportions of reducing agent result in no isolable organocobalt(III) complex presumably due to decomposition of the alkylating agent and/or decomposition of 1 by the excess NaBH4 to give (CF3)2CFH, as demonstrated by 19F NMR spectroscopy. The reduction of 1 with NaBH4 is proposed to proceed through the intermediacy of (CF3)2CF- and Na[pyCo(DH)2] from deuterium-labeling studies. Synthetic methodology is also reported for the preparation of LCo(DH)2[CF(CF3)2], where L = H2O, 4-tert-butylpyridine (4-t-Bupy), and P(OCH3)3. Complex 1 crystallizes in the monoclinic space group P21/m, with a = 9.013 (2) Å, b = 13.524 (4) Å, c = 9.412 (2) Å, β = 101.07 (2)°, V = 1125.8 (5) Å3, and Z = 2, and was refined to R = 0.049. The structure is characterized by large distortions due to the bulky alkyl group. Comparisons are made to pyCo(DH)2[CH(CH3)2], the structure of which had previously been determined.

Original languageEnglish (US)
Pages (from-to)2101-2105
Number of pages5
JournalInorganic Chemistry
Volume29
Issue number11
StatePublished - 1990
Externally publishedYes

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ASJC Scopus subject areas

  • Inorganic Chemistry

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