Abstract
Reduction of [Co(CNBut)5][PF6] with potassium amalgam in tetrahydrofuran affords red air-sensitive crystals of octakis(t-butyl isocyanide)dicobalt. Crystals of [Co2(CNBut)8] are orthorhombic, space group P21212, with two molecules in a cell of dimensions a = 18.017(4), b = 12.149(4), and c = 11.382(5) Å. The structure has been solved by conventional techniques and refined by least squares to R 0.085 for 2 376 reflection intensities recorded on a four-circle diffractometer. The molecular geometry resembles that of [CO2(CO)8], but is substantially distorted, especially with respect to one of the basal isocyanide functions. Non-bonded contacts calculated for an idealized molecular geometry strongly suggest the importance of intermolecular contacts in the adopted distortions. The cobalt-cobalt distance is 2.4567(20) Å. The 13C n.m.r. spectrum of an enriched (10%) sample of [Co2( CNBut)8] shows one resonance at ambient temperature collapsing (coalescence temperature -60 °C) to three resonances (1:1:2) at -90 °C. Evidence is presented for an intramolecular exchange process. Reaction of [Co2(CNBut)8] with CO, NO, and diphenylacetylene affords respectively [Co(CNBut)5][Co(CO)4], [Co(CNBut)3-(NO)], and [Co2{μ-(η2-PhC2Ph)}(CNBu t)6].
Original language | English |
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Pages (from-to) | 80-86 |
Number of pages | 7 |
Journal | Journal of the Chemical Society, Dalton Transactions |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Dec 1980 |
Externally published | Yes |