Heterometalation of 1,1′-Bis(ortho-carborane)

• Published in: Inorganic chemistry Vol. 57; no. 13; pp. 8002 - 8011
• Main Authors: Chan, Antony P. Y, Rosair, Georgina M, Welch, Alan J
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02-07-2018
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.8b01166

Deboronation of [8-(1′-closo-1′,2′-C2B10H11)-closo-2,1,8-MC2B9H10] affords diastereoisomeric mixtures of [8-(7′-nido-7′,8′-C2B9H11)-closo-2,1,8-MC2B9H10]− anions (1, M = Ru­(p-cymene); 2, M = CoCp) isolated as [HNMe3]+ salts. Deprotonation of 1 and reaction with CoCl2/NaCp followed by oxidation yields [8-(1′-3′-Cp-closo-3′,1′,2′-CoC2B9H10)-2-(p-cymene)-closo-2,1,8-RuC2B9H10] isolated as two separable diastereoisomers, namely, 3α and 3β, the first examples of heterometalated derivatives of 1,1′-bis­(ortho-carborane). Deprotonation of [7-(1′-closo-1′,2′-C2B10H11)-nido-7,8-C2B9H11]−, metalation with CoCl2/NaCp* and oxidation affords the isomers [1-(1′-closo-1′,2′-C2B10H11)-3-Cp*-closo-3,1,2-CoC2B9H10] (4) and [8-(1′-closo-1′,2′-C2B10H11)-2-Cp*-closo-2,1,8-CoC2B9H10] (5) as well as a trace amount of the 13-vertex/12-vertex species [12-(1′-closo-1′,2′-C2B10H11)-4,5-Cp*2-closo-4,5,1,12-Co2C2B9H10] (6). Reduction then reoxidation of 4 converts it to 5. Deboronation of either 4 or 5 yields a diastereoisomeric mixture of [8-(7′-nido-7′,8′-C2B9H11)-2-Cp*-closo-2,1,8-CoC2B9H10]− (7), again isolated as the [HNMe3]+ salt. Deprotonation of this followed by treatment with [RuCl2(p-cymene)]2 produces [8-(1′-3′-(p-cymene)-closo-3′,1′,2′-RuC2B9H10)-2-Cp*-closo-2,1,8-CoC2B9H10] (8) as a mixture of two diastereoisomers in a 2:1 ratio, which could not be separated. Diastereoisomers 8 are complementary to 3α and 3β in which {CoCp} and {Ru­(p-cymene)} in 3 were replaced by {Ru­(p-cymene)} and {CoCp*}, respectively, in 8. Finally, thermolysis of mixture 8 in refluxing dimethoxyethane yields [8-(8′-2′-(p-cymene)-closo-2′,1′,8′-RuC2B9H10)-2-Cp*-closo-2,1,8-CoC2B9H10] (9), again as a 2:1 diastereoisomeric mixture that could not be separated. All new species were characterized by multinuclear NMR spectroscopy, and 3α, 3β, 4, 5, 6, and 9 were also characterized crystallographically.