Synthesis, characterization, and reactions of tetrakis(nitrile)chromium(II) tetrafluoroborate complexes

Rui T. Henriques, Eberhardt Herdtweck, Fritz E. Kühn, André D. Lopes, Janos Mink, Carlos C. Romão

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Reaction of chromium(II) acetate with HBF4 in nitrile solutions led to air-sensitive, paramagnetic complexes of the general formula [Cr(NCR)4][BF4]2 (R = Me, But or Ph). In contrast to an earlier report of the synthesis of [Cr(NCMe)4][BF4]2 by electrochemical methods, these compounds are blue. The crystal structure of [Cr(NCMe)4][BF4]2 has been determined. The chromium(II) cation is surrounded by nitrile ligands in a square-planar manner. The BF4- counter ions are located at the apical positions of an elongated octahedron. Magnetic susceptibility measurements yielded μeff = 4.9 μB at 300 K which is characteristic for a d4 high-spin complex. The paramagnetic complexes [Cr(NCR)4][BF4]2 are easy to prepare and can be used for the high-yield synthesis of several other chromium derivatives in low oxidation states like [Cr(py)4][BF4]2, [Cr(C5H5)2], [Cr(dppe)2][BF4]2 and [Cr(NO)(NCMe)5][BF4]2.

Original languageEnglish
Pages (from-to)1293-1297
Number of pages5
JournalJournal of the Chemical Society - Dalton Transactions
Issue number8
Publication statusPublished - Apr 21 1998

ASJC Scopus subject areas

  • Chemistry(all)

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