Synthesis and luminescence of monohalogenated B18H22 clusters

This work advances the foundation of anti-B18H22 chemistry by exploring cluster reactivity in the context of monohalogenation and the luminescent properties of the resulting compounds. The synthesis and photo -luminescent properties of new anti-B18H22 derivatives 4-I-B18H21 and 7-Cl-B18H21 are described and bench -marked against other existing monohalogenated species reported previously. Electrophilic halogenation utilizing AlCl3 and I2 produces iodination at the B4 vertex to produce 4-I-B18H21 in 43 % isolated yield. This compound exhibits oxygen-insensitive phosphorescence at 514 nm (Phi = 0.16). Chlorination of the B7 vertex through treatment of the parent borane with N-chlorosuccinimide and hydrochloric acid gives 7-Cl-B18H21 in 76 % isolated yield, which produces fluorescent emission at 418 nm and exhibits one of the highest quantum yields of B18H22 derivatives reported to date, Phi = 0.80.

Automated summary

This work advances the foundation of anti-B18H22 chemistry by exploring cluster reactivity and the luminescent properties of resulting compounds. The synthesis and luminescent properties of new anti-B18H22 derivatives 4-I-B18H21 and 7-Cl-B18H21 are described and compared to existing monohalogenated species. The results show that electrophilic halogenation and chlorination can be used to synthesize anti-B18H22 compounds with different luminescent properties.