110015-89-9Relevant academic research and scientific papers
Organotransition-metal metallacarboranes. 11. Chromium tricarbonyl η6-complexes of nido-2,3-(PhCH2)2C2B4H6: Metal complexation and oxidative fusion
Whelan, Thomas,Spencer, James T.,Pourian, Mohammad R.,Grimes, Russell N.
, p. 3116 - 3119 (2008/10/08)
The consequences of η6-phenyl coordination of Cr(CO)3 groups on the chemistry of the C,C′-dibenzylcarborane nido-2,3-(PhCH2)2C2B4H6 (1) were investigated. The monochromium species [(CO)3Cr](PhCH2)2C2B 4H6 (2) underwent bridge (B-H-B) deprotonation by NaH in THF, and the resulting anion, on treatment with FeCl2, formed [[(CO)3Cr](PhCH2)2C2B 4H4]2FeH2 (not isolated); subsequent oxidation with O2 gave two isomers of [(CO)3Cr]2(PhCH2)4C 4B8H8 (7A,B), which were characterized spectroscopically. Reaction of the tetracarbon carborane (PhCH2)4C4B8H8 (5) with Cr(CO)6 gave dichromium products identical with 7A,B but no other isomers. An attempted analogous sequence with [(CO)3Cr]2(PhCH2)2C 2B4H6 (3) proceeded only as far as bridge deprotonation with KH; the resulting anion on treatment with FeCl2/O2 did not undergo fusion, nor was fusion observed with other transition metals. An attempted mixed-ligand fusion of the anions of 1 and 3 gave only 5 and the original substrate 3. Deprotonation of 3 was shown to proceed cleanly, via deuteriation of the anion to produce monodeuteriated 3. The resistance of 3 to oxidative fusion is discussed in terms of steric and electronic effects.
