Effect of Iodination on the Photophysics of the Laser Borane -BH: Generation of Efficient Photosensitizers of Oxygen.

Treatment of the laser borane -BH (compound ) with iodine in ethanol gives the monoiodinated derivative 7-I--BH (compound ) in 67% yield, or, by reaction with iodine or ICl in the presence of AlCl in dichloromethane, the diiodinated derivative 4,4'-I--BH (compound ) in 85% yield. On excitation with 360 nm light, both compounds and give strong green phosphorescent emissions (λ = 525 nm, Φ = 0.41 and λ = 545 nm, Φ = 0.

A borane laser.

Emission from electronically excited species forms the basis for an important class of light sources-lasers. So far, commercially available solution-processed blue-emitting laser materials are based on organic compounds or semiconductor nanocrystals that have significant limitations: either low solubility, low chemical- and/or photo-stability and/or uncompetitive prices. Here we report a novel and competitive alternative to these existing laser materials that is based on boron hydrides, inorganic cluster compounds with a rich and diverse chemistry.

Tuning the photophysical properties of anti-B18H22: efficient intersystem crossing between excited singlet and triplet states in new 4,4'-(HS)2-anti-B18H20.

The tuning of the photophysical properties of the highly fluorescent boron hydride cluster anti-B18H22 (1), by straightforward chemical substitution to produce 4,4'-(HS)2-anti-B18H20 (2), facilitates intersystem crossing from excited singlet states to a triplet manifold. This subsequently enhances O2((1)Δg) singlet oxygen production from a quantum yield of ΦΔ ∼ 0.008 in 1 to 0.