4 Boron

Abstract

Molecular wheels of eight- and nine-atom boron clusters have been observed by photoelectron spectroscopy and their structures confirmed by DFT calculations. The first cationic terminal borylene, containing a FeB double bond, [Cp*Fe(CO)₂(Bmesityl)][BAr_f4] has been synthesised. DFT calculations support a bonding model in which boron engages in π-bonding to both [Cp*Fe(CO)₂]⁺ and mesityl moieties. The first thirteen vertex carborane has been prepared by successive reduction of 1,2-μ-{C₆H₄(CH₂)₂}-1,2-closo-C₂B₁₀H₁₀ with Na to afford the [7,8-μ-{C₆H₄(CH₂)₂}-7,8-nido-C₂B₁₀H₁₀]²⁻ ion followed by addition of PhBCl₂ to give the unprecedented 13-vertex carborane 1,2-μ-{C₆H₄(CH₂)₂}-3-Ph-1,2-C₂B₁₁H₁₀ which has a henicosahedral structure.