Boryl- and amino-substituted acetylenes would have a butatriene-type resonance contribution due to the interaction between boron empty orbital and nitrogen lone pair. However, a few examples of boryl- and amino-substituted acetylenes have been synthesized up to date, and structural analysis by X-ray crystallography has remained unknown. Here we report the synthesis and characterization of dimesitylboryl- and diethylamino-substituted acetylene. In addition to the spectroscopic studies, the X-ray crystallography of the acetylene revealed the lengthening of the triple bond and the shortening of C–B and C–N bonds, being consistent with the butatriene-type resonance contribution.

The synthesis of a donor-acceptor cyclobutadiene featuring a boryl/amino-substitution pattern is presented together with its characteristic reactivity toward water. On the basis of the results of X-ray crystallography, theoretical studies, and spectroscopic analyses, the observed rhombic structure of the cyclobutadiene was attributed to a charge-separated electronic structure. Reaction of this boryl-substituted cyclobutadiene with water induced a characteristic migration of the boryl group, due to the Lewis acidity of the boryl-substituent.

Greenhouse-gas emissions and energy shortages are critical problems that need to be solved. Developing novel catalytic materials that can reduce greenhouse gases like carbon dioxide and convert them to fuels...