A Series of Ultra-Efficient Blue Borane Fluorophores

Abstract

We present the first examples of alkylated derivatives of the macropolyhedral boron hydride, anti-B 18 H 22 -which is the gain medium in the first borane laser. This new series of ten highly-stable and colourless organic-inorganic hybrid clusters are capable of the conversion of UVA irradiation to blue light with fluorescence quantum yields of unity. This study gives a comprehensive description of their synthesis, isolation and structural characterization together with a delineation of their photophysical properties using a combined theoretical and experimental approach. Treatment of anti-B 18 H 22 1 with RI (where R = Me or Et) in the presence of AlCl 3 gives a series of alkylated derivatives, R x -anti-B 18 H 22-x (where x = 2 to 6), compounds 2-6, in which the 18-vertex octadecaborane cluster architectures are preserved and yet undergo a linear "polyhedral swelling", depending on the number of cluster alkyl substituents. The use of dichloromethane solvent in the synthetic procedure leads to dichlorination of the borane cluster and increased alkylation to give Me 11 -anti-B 18 H 9 Cl 2 11, Me 12 -anti-

Direct Phenylation of nido-B10H14

“… a λ F is the maximum of fluorescence emission band; τ F is the fluorescence lifetime; and Φ F is the fluorescence quantum yield. b Taken from ref . c Intensity average lifetime, excited at 337 nm, emission recorded at 400, 430, 450, or 500 nm; biexponential fitting. d Excited at 337 nm, emission recorded at fluorescence maxima. e Excited at 310, 320, 330, 340, or 350 nm. …”

Macropolyhedral Chalcogenaboranes: Insertion of Selenium into the Isomers of B18H22

“…Figure below shows a stick diagram of the 11 B chemical shifts together with those of related compounds for comparison. Many of the boron resonances were too broad and too closely spaced to allow efficient assignment of the peaks from [ 11 B– 11 B] COSY correlations, but this compound does present a useful example of the utility of multielement DFT/GIAO simulation of NMR spectra and its use in assigning measured resonances to their positions in the cluster. , The technique is applied to the assignments made for other compounds herein.…”

Incorporation of the New anti-Octadecaborane Laser Dyes into Thin Polymer Films: A Temperature-Dependent Photoluminescence and Infrared Spectroscopy Study

“…In detail, the anti -B 18 H 22 spectral band has been detected at 407 nm with quantum yield (QY) 0.97 when measured in hexane [ 24 ]. Moreover, this emission maximum ( λ maxEm ) is tunable by adjustment of anti -B 18 H 22 molecular structure via substitution of hydrogens with e.g., alkyl- groups 3,3′,4,4′-Me 4 - anti -B 18 H 18 and 3,3′,4,4′-Et 4 - anti -B 18 H 18 ( λ maxEm = 424 and 427 nm, respectively, QY = 1, both) [ 25 ], sulphur 4,4′-(HS) 2 - anti -B 18 H 20 ( λ maxEm = 536 nm) [ 29 ], or iodine 4,4′-I 2 - anti -B 18 H 20 (λ maxEm = 545 nm with QY = 0.71) [ 30 ].…”

“…Poly(dimethylsilane-methylphenylsilane) (PDMSi-MPSi; M w ~ 82,000, M n ~ 18,000) was obtained from Fluorochem Ltd., and polycarbonate Makrolon (PC, M w ~ 58,000, M n ~ 25,000) was obtained from Bayer. Octadecaborane anti -B 18 H 22 (B, M = 216.58 g/mol) and its tetra-alkylated derivatives 3,3′,4,4′-Et 4 - anti -B 18 H 18 (BEt, M = 328.66 g/mol) and 3,3′,4,4′-Me 4 - anti -B 18 H 18 (BMe; M = 272.62 g/mol) were synthesized at the Institute of Inorganic Chemistry of the AS CR [ 25 ].…”

“…The purpose of this study is to describe anti -octadecaborane(22) (in-text abbrev., B) and its derivatives 3,3′,4,4′-Me 4 - anti -B 18 H 18 (BMe) and 3,3′,4,4′-Et 4 - anti -B 18 H 18 (BEt) in thin polymer films and their response to a change in the film temperature. These borane clusters were chosen to represent the new borane-based laser dyes because they have shown promising results of stable PL with efficient blue emission [ 24 , 25 ]. However, our first observation within photoluminescence spectra indicated that the intensity of emission maximum of borane clusters decreased as the temperature of the film increased until it fell below the detection limit at a specific temperature.…”