Synthesis, structure and DFT calculations of 1,2-N-substituted o-carboranes

Abstract

A series of 1,2-N-substituted o-carboranes were obtained. Ultra-long C–C distances were found in the secondary-amino o-carboranes 3. The relationship between C–C bond lengths and the electron effects of the benzyl groups was discussed.

Redox-active carborane clusters in bond activation chemistry and ligand design

“…[50][51][52] There have been theoretical studies of the electronic and steric effects of exohedral substituents on this C-C bond length. 53,54 The electronic interaction between exohedral donor groups and the carborane cluster can be very significant, as evidenced by the recently disclosed structure of the diamine derivative 1,2-(MesCH 2 NH) 2 -C 2 B 10 H 10 , which features one of the longest reported C-C bonds (1.931(3) Å, cf. 1.624(8) Å for the parent unsubstituted cluster).…”

Expanding the Scope of Palladium-Catalyzed B–N Cross-Coupling Chemistry in Carboranes

“…Surprisingly, 1-NCO- o -carborane has a reported ν NCO value of 2258 cm –1 : on the basis of inductive effects, it would be expected that the stretching frequency would be even higher than that of the B(3) derivative. However, Teixidor and others have previously suggested that C-bound substituents with available lone pairs can donate electron density back into the cage with concomitant C–C bond lengthening, which may in part explain the deviation in this trend. Unfortunately, at this point we are unable to compare this observation with the analogous azide system.…”

Cyclic Carbonate Synthesis from Epoxides and CO2 Catalyzed by Aluminum–Salen Complexes Bearing a nido-C2B9 Carborane Ligand

“…We have reported the facile synthesis and functionalization of diamino o -carborane (Chart ). These secondary amino o -carboranes were used as supporting ligands for N -heterocyclic carbenes and the carbene complexes . We envisioned the diamino o -carborane could also be used to synthesize salen-type ligands and metal–salen complexes (Chart ).…”