Taming the parent oxoborane?

Chemical Science Pub Date: 2023-04-26 DOI: 10.1039/D3SC01544K

Abstract

Despite recent advancements in the chemistry of multiply bound boron compounds, the laboratory isolation of the parent oxoborane moiety, HBO has long remained an unsolved and well-recognized challenge. The reaction of 6-SIDipp·BH3 [6-SIDipp = 1,3-di(2,6-diisopropylphenyl)tetrahydropyrimidine-2-ylidene] with GaCl3 afforded an unusual boron–gallium 3c–2e compound (1). The addition of water to 1 resulted in the release of H2 and the formation of a rare acid stabilized neutral parent oxoborane, LB(H)[double bond, length as m-dash]O (2). Crystallographic and density functional theory (DFT) analyses support the presence of a terminal B[double bond, length as m-dash]O double bond. Subsequent addition of another equivalent of water molecule led to hydrolysis of the B–H bond to the B–OH bond, but the ‘B[double bond, length as m-dash]O’ moiety remained intact, resulting in the formation of the hydroxy oxoborane compound (3), which can be classified as a monomeric form of metaboric acid.

Graphical abstract: Taming the parent oxoborane
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