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We report here a straightforward reductive approach for the deoxygenation, activation and functionalization of ultrashort single-walled carbon nanotubes (us-SWCNTs). Us-SWCNTs with lengths of only 20–50 nm were prepared by the low-temperature oxidative-cutting process which inevitably introduced oxygen-containing groups onto the nanotube framework. For the subsequent deoxygenation, six routes have been investigated and the reduction with potassium is the optimal one that can efficiently remove the oxidized groups and consequently recover the inherent structures and properties of us-SWCNTs. This reductive approach permits at the same time very efficient activation of the chemically inert nanotubes by generating the intermediate us-SWCNTn- carbanions. Subsequent quenching these negative charges on the nanotube backbone using electrophiles affords very efficient covalent binding of distinct building blocks as porphyrin, phenyl or hexyl moieties onto us-SWCNTs. Additionally, the Birch-type reductive approach was also performed to realize the first hydrogenation of us-SWCNTs by using water as proton source and lithium as reducing agent.

The development of highly efficient and stable blue-emitting dyes to overcome some of the most important shortcomings of available chromophores is of great technological importance for modern optical, analytical, electronic, and biological applications. Here, we report the design, synthesis and characterization of new tailor-made BODIPY dyes with efficient absorption and emission in the blue spectral region. The major challenge is the effective management of the electron-donor strength of the substitution pattern, in order to modulate the emission of these novel dyes over a wide spectral range (430-500 nm). A direct relationship between the electron-donor character of the substituent and the extension of the spectral hypsochromic shift is seen through the energy increase of the LUMO state. However, when the electron-donor character of the substituent is high enough, an intramolecular charge-transfer process appears to decrease the fluorescence ability of these dyes, especially in polar media. Some of the reported novel BODIPY dyes provide very high fluorescence quantum yields, close to unity, and large Stokes shifts, leading to highly efficient tunable dye lasers in the blue part of the spectrum; this so far remains an unexploited region with BODIPYs. In fact, under demanding transversal pumping conditions, the new dyes lase with unexpectedly high lasing efficiencies of up to 63 %, and also show high photostabilities, outperforming the laser action of other dyes considered as benchmarks in the same spectral region. Considering the easy synthetic protocol and the wide variety of possible substituents, we are confident that this strategy could be successfully extended for the development of efficient blue-edge emitting materials and devices, impelling biophotonic and optoelectronic applications.

A new and facile strategy for the development of photonic materials is presented that fufills the conditions of being efficient, stable, and tunable laser emitters over the visible region of spectrum, with the possibility of being easily processable and cost-effective. This approach uses poly(methyl methacrylate) (PMMA) as a host for new dyes with improved efficiency and photostability synthesized. Using a simple protocol, fluorine atoms in the commercial (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) (F-BODIPY) by carboxylate groups. The new O-BODIPYs exhibit enhanced optical properties and laser behavior both in the liquid and solid phases compared to their commercial analogues. Lasing efficiencies up to 2.6 times higher than those recorded for the commercial dyes are registered with high photostabilities since the laser output remain at 80% of the initial value after 100 000 pump pulses in the same position of the sample at a repetition rate of 30 Hz; the corresponding commercial dye entirely loses its laser action after only 12 000 pump pulses. Distributed feedback laser emission is demonstrated with organic films incorporating new O-BODIPYs deposited onto quartz substrates engraved with appropriated periodical structures. These dyes exhibit laser thresholds up to two times lower than those of the corresponding parent dyes with lasing intensities up to one order of magnitude higher. The development of new O-BODIPYs, synthesized via the replacement of fluorine atoms by carboxylate groups in commercial (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) (F-BODIPYs), is a successful strategy to obtain optimized laser dyes. Poly(methyl methacrylate) (PMMA) doped with these new derivatives leads to laser materials that are economically affordable and have optimized emission properties in the visible spectral region. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

3 pags, 3 figs, 2 tabs, A cassette molecule, featuring direct integration of two donor BODIPY units to one acceptor BODIPY unit, was conveniently developed as the first highly "through-bond energy transfer" (TBET) laser dye. This multicolor absorbing dye exhibited highly efficient and photostable laser action under drastic pumping conditions. © 2011 The Royal Society of Chemistry., Y. X. thanks National Natural Science Foundation of China (No. 20876022) and the Fundamental Research Funds for the Central Universities (No. DUT10ZD114), and I. G.-M. and I. L. A. thank Spanish MICINN (MAT2010-20464-C04-01 and -C04-4, respectively, and TRACE2009-0144) for financial support.

9 pags, 5 figs, 2 tabs, Highly efficient and photostable laser parameters were observed for the diiodinated BODYPY derivatives 1 – 3 both in liquid phase and incorporated into polymeric matrices. The laser samples were transversely pumped at wavelengths near their absorption maxima (515 and 532 nm) at 5 mJ/pulse and 10 Hz repetition rate; these are conditions that would induce photodegrdation of many laser-active fluors. Under these extreme conditions, the new dyes exhibit laser action from 530 nm to 625 nm with remarkable efficiencies, up to 55% in liquid solutions and 45% in poly(methylmethacrylate), and with high photostability since the laser output remains at the initial level, with no sign of degradation, after 100000 pump pulses in the same position of the sample. The efficiencies and photo stabilities of the new dyes outperform those of one presently commercialized and considered benchmarks over this spectral region (i.e. coumarines, xanthenes, perilendiimides). The enhanced optical properties recorded under drastic laser pumping conditions suggest that these new photonic systems could be outstanding in biophotonic applications like optical microscopy and nanoscopy, since they would allow very long observation times and improved spatial resolution, This work was supported by the Spanish MICINN (Projects MAT2010-20646-C04-01 and TRACE2009-0144), and by the National Institutes of Health (GM0879811) and The Robert Welch Foundation (A-1121).

Asymmetrically substituted BODIPY analogues of the dye PM567 have been synthesised from 2-acylpyrroles and pyrroles that bear indene, fluorene or difluorene units. The type of linkage between the fluorene and the BODIPY core plays an important role in the photophysics of the BODIPY chromophore. Indeed, an aliphatic bridge gives rise to an energy-transfer process between the chromophores, whereas a vinyl spacer allows an electronic interaction between them, leading to a large red shift of the spectral bands. The laser action of the new dyes has been analysed under transversal pumping at 10 Hz repetition rate, in both liquid phase and incorporated into solid polymeric matrices. Lasing efficiencies of up to 40 % were reached with high photostabilities with the laser output remaining at the initial level after 1 x 10 5 pump pulses in the same position of the sample. The laser action of the new dyes outperforms the laser behaviour of commercial dyes that emit in the same spectral region. The replacement of fluorene by indene quenches the fluorescence and laser emission, but allows the development of an iron cation fluorescent sensor.

By comparison and combination of two strategies, extending π-conjugation and tuning Intramolecular Charge Transfer (ICT) effect, new long-wavelength BODIPY dyes have been efficiently synthesized. The new chromophores exhibit good optical properties: high fluorescence quantum yields, exceptionally large molar extinction coefficients, narrow red-emission bands, and relatively large Stokes shifts etc., in polar or apolar solvents. Besides, the new dyes, under transversal pumping at 532 nm, exhibit highly efficient and stable laser emission tunable from the green to NIR spectral region (570-725 nm). Moreover, one of these new BODIPY derivatives shows cell membrane permeability and bright intracellular red fluorescence. These advantageous characteristics assure the potential of these dyes for biophotonic applications.