Accession Number : ADA022758

Title :   Cobalt-Hydrogen Metallocarboranes. Synthesis of Closo- ((CH 3)2C2B4H4)2CoH and Nido-Closo-((CH3)2C2B3H5)CoH((CH3)2C2B4H4) and Their Conversion to New Cobalt-Cobalt Bonded Metallocarboranes.

Descriptive Note : Interim technical rept.,


Personal Author(s) : Maxwell,William M. ; Miller,Vernon R. ; Grimes,Russell N.

Report Date : FEB 1976

Pagination or Media Count : 39

Abstract : The reaction of Na(+)((CH3)2C2B4H5)(-) with CoCl2 at 25C yields the red neutral commo-metallocarborane (C,C'-(CH3)2C2B4H4)2Co(III)H. From NMR evidence the hydrogen atom associated with the metal is proposed to be face-bonded to a triangular face on the polyhedral surface. The compound is converted in aqueous acid to a nido-closo species, (C,C'-(CH3)2C2B3H5)CoH(C,C'-(CH3)2C2B4H4), which in turn can be metal-deprotonated by NaH to give the ((CH3)2C2B3H5)Co((CH3)2C2B4H4)(-) ion; reaction of the latter species with aqueous HCl regenerates the neutral metal-protonated compound. The reaction of the ion with CoCl2 and NaC5H5 produces nido-closo ((CH3)2C2B3H5)CoH((CH3)2C2B3H3)Co(eta to the 5th power-C5H5) in which a Co-Co bond is postulated. Treatment of (C,C'-(CH3)2C2B4H4)2Co(III)H with (eta to the 5th power-C5H5)Co(CO)2 yields 4,5 - (CH3)2-1,2,4,5-(eta to the 5th power-C5H5)2Co2C2B3H3 and (eta to the 5th power-C5H5)Co((CH3)2C2B3H3)CoH((CH3)2C2B3H3)Co(eta to the 5th power-C5H5), the latter species having a proposed Co-Co link. Air-oxidation of (C,C'-(CH3)2C2B4H4)2Co(III)H produces the tetracarbon carborane (CH3)4C4B8H8.

Descriptors :   *Synthesis(Chemistry), *Carboranes, *Metalorganic compounds, Nuclear magnetic resonance, Cobalt compounds, Chemical bonds

Subject Categories : Organic Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE