The periodinated closo-dodecaborate ion [B12I12]2- has a highly stable icosahedral structure. We have recently shown that a homolytic cleavage of one B-I bond in this ion in the gas phase results in the formation of the radical dianion [B12I11]2-. .This ion reacted with residual O2 gas in the trap a linear quadrupole ion trap (LQIT) mass spectrometer (MS) – a reaction typically observed for radical cations. The purpose of this study was to characterize the chemical nature of this atypical radical dianion containing a localized free binding site in the icosahedral boron core. The gas-phase reactivity of this ion toward a variety of reagents such as acrylonitrile and allyl iodide have been studied in LQIT-MS. Remarkably, [B12I11]2-. reacted efficiently with electron-rich neutral reagents, such as allyl iodide, that usually react rapidly with electrophilic cations. In addition to [B12I11]2-., the reactivity of two singly charged carborate radicals, [HCB11I10]-. (with the radical site localized on a boron atom) and [CB11I11]-. (with the radical site localized on a carbon atom) were examined. Studies on reaction kinetics have shown consistently that the radical anion with the free binding site on boron has a greater reactivity than that with the free binding site on carbon. Natural population analysis revealed that the free boron site actually carries a positive charge in both [HCB11I10]-. and [B12I11]2-., while the free but less reactive carbon in [CB11I11]-. has a negative charge. This finding indicates that the radical anions investigated here may be classified as electrophilic radicals, although they are anions.

Chemical characterization of boron-centered radical anion

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.