Macropolyhedral boron-containing cluster chemistry. A synthetic approach via the auto-fusion of [6,9-(SMe2)(2)-arachno-B10H12]

摘要

In an attempt to build up borane-based multicluster assemblies, thermolysis of [6,9-(SMe2)(2)-arachno-B10H12] 1 in inert hydrocarbon solution, followed by chromatographic separation, has resulted in the isolation not only of the previously established single-cluster product from this reaction, [5-(SMe2)-nido-B10H12] 2 (30%), but also the two two-cluster species [6,9-(SMe2)(2)-arachno-B10H11-1-(6'-nido-B10H13)] 3 (20%) and [1,6'-(nido-B10H13)(2)] 6 (ca. 0.5%) and the two three-cluster species [6,9-(SMe2)(2)-arachno-B10H10- 1,5-(6'-nido-B10H13)(2)]4 (5%), characterized crystallographically, and [6,9-(SMe2)(2)-arachno-B10H10-1,3-(6'-nido-B10H13)(2)] 5 (< 1%), identified by NMR spectroscopy. An improved crystallographic investigation of [5-(SMe2)-nido-B10H12] 2 is also presented. The feasibility of the stability of species resulting from multiple adjacent substitution of nido-decaboranyl units on the [6,9-(SMe2)(2)-arachno-B10H12] skeleton is tested by DFT calculations. In an extension, to attempt the use of pre-sigma-linked two-cluster compounds as starting substrates, two-cluster [5-(SMe2)-4-(2'- nido-B10H13)-nido-B10H11] 7 (0.6%) has been isolated from the reaction of SMe2 with [1,5'-(nido-B10H13)(2)], other identified products being compound 1 (39%) and compound 3 (10.5%).