1,3,2-dioxaborines as potential components in advanced materials - A theoretical study on electron affinity

1,3,2-Dioxaborines with fluorine and other substituents at boron were calculated by first-principles methods based on density functional theory (DFT: B3-LYP) or many-body perturbation theory at the second order [MBPT(2): MP2]. 1,3,2-Dioxaborines are derivatives of 1,3-dicarbonyl compounds also known as 1,3-diketoborates. According to quantum chemical calculations, 2,2-difluoro-1,3,2-dioxaborines are of puckered structure with a low barrier to inversion. The calculated charge distribution does not reflect well the traditional formula description. The boron atom carries a positive rather than a negative charge. Some compounds have a pronounced zwitterionic character accompanied by relatively high dipole moments. The calculated positive electron affinities (EAs) classify 1,3,2-dioxaborines as organic electron-acceptor compounds. Depending on the type of substitution, the EAs vary between about 0.5 and 3.5 eV (DFT calculations). The EAs of various substituted 1,3,2-dioxaborines are of the same order of magnitude as those of quinones and close to electron affinities of strong organic acceptor compounds such as tetracyanoethylene (TCNE). Numerical predictions are verified by comparison with EAs of a series of well-known medium-sized organic compounds studied experimentally and theoretically at the same level of theory. In good agreement with results reported for other series of compounds, the average absolute error between theoretical and experimental EAs was 0.19 eV. Because of the ability of 3,5-diaryl-2,2-difluoro-1,3,2-dioxaboranes to fluoresce efficiently and to accept electrons easily, these compounds are potential candidates for future applications. Copyright (C) 2004 John Wiley Sons, Ltd.