Tuning the Photophysical Properties of anti-B₁₈H₂₂: Efficient Intersystem Crossing between Excited Singlet and Triplet States in New 4,4′-(HS)₂-anti-B₁₈H₂₀.

Abstract

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 0.59 in 2. This paper describes the synthesis and full structural characterization of the new compound 4,4'-(HS)2-anti-B18H20 (2) and uses UV-vis spectroscopy coupled with density functional theory (DFT) and ab initio computational studies to delineate and explain its photophysical properties.

Antimicrobial and optical properties of PET chemically modified and grafted with borane compounds

“…The borane compounds used in this work, anti-B 18 H 22 (B1) and 4,4 0 -(HS) 2 -anti-B 18 H 20 (B2), were synthesized according to a published procedure. 23,41,42 The chemical graing procedure has been described previously. 5,16,34,43 b. Analytical methods Surface properties, before and aer each step of activation and/ or chemical modication, were characterized using electrokinetic analysis, X-ray photoelectron spectroscopy, goniometry and UV-vis spectroscopy.…”

“…They create three-dimensional clusters with many interesting and important properties, such as high uorescence yield 22 and the production of singlet oxygen. 23 Singlet oxygen can be used in photodynamic therapy, in photomedicine for cancer treatment [24][25][26] or for uses connected with its antimicrobial effects. 27,28 Fluorescence can be used in chemical sensors (uorescence spectroscopy), 29,30 uorescent dyes 31,32 or biological detectors.…”

Substitution of the laser borane anti-B18H22 with pyridine: a structural and photophysical study of some unusually structured macropolyhedral boron hydrides

“…Photophysical Considerations. There is a strongly developing theme of useful fluorescence from the macropolyhedral borane compound anti-B18H22 1 5,15 and its derivatives, 41 including B18H20Py2 (compound 2) 28 of which preparative and NMR spectroscopic aspects are now also dealt with in this present paper. Consequently, we are interested in a rationalisation of the weak luminescence that we have found for compound 3a during the course of this present work, and the contrasting nonfluorescence of B18H20-8′-Py (compound 4), as part of an overall and fuller understanding of the photochemistry of macropolyhedral boranes.…”

“…Factors limiting the solubility of B16H18Py2 3a and its picoline congener 3b, of which both have such limited solubility, and of which both have very similar molecular structures, are conveniently dealt with in this present paper. The fluorescence of 2 merits more detailed specialist photophysical investigation, particularly in the light of the ongoing revelation of the fluorescence of anti-B18H22, 15 the fine tuning and precise tailoring of the fluorescence properties of B18H22 by substituent chemistry, 41 and, cumulatively, by the milestone utilisation of the fluorescence properties for anti-B18H22 to devise the first borane laser. 5 The interesting specific fluorescence properties of B18H20Py2 2 are dealt with in detail in a contemporaneous submission.…”

Thermochromic Fluorescence from B18H20(NC5H5)2: An Inorganic–Organic Composite Luminescent Compound with an Unusual Molecular Geometry

“…[15] Consequently, we are interested in expanding the portfolio of luminescent macropolyhedral borane systems in an effort to delineate the full potential of this new class of laser materials. To this end, we have begun a systematic investigation of derivatives of anti-B 18 H 22 (1), [16] and here we report on the interesting photophysical properties of the luminescent compound B 18 H 20 (NC 5 H 5 ) 2 (2) formed from the reaction of anti-B 18 H 22 with pyridine.…”