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We compare the stability of [n]cycloparaphenylene ([n]CPP)-based host–guest complexes with Li+@C60 and C60 in the gas and solution phase. Our experiments reveal a significant increase in stability for the complexes featuring [9–12]CPP with Li+@C60.

We investigate the gas‐phase chemistry of noncovalent complexes of [10]cycloparaphenylene ([10]CPP) with C60 and C70 by means of atmospheric pressure photoionization and electrospray ionization mass spectrometry. The literature‐known [1 : 1] complexes, namely [10]CPP⊃C60 and [10]CPP⊃C70, are observed as radical cations and anions. Their stability and charge distribution are studied using energy‐resolved collision‐induced dissociation (ER‐CID). These measurements reveal that complexes with a C70 core exhibit a greater stability and, on the other hand, that the radical cations are more stable than the respective radical anions. Regarding the charge distribution, in anionic complexes charges are exclusively located on C60 or C70, while the charges reside on [10]CPP in the case of cationic complexes. [2 : 1] complexes of the ([10]CPP2⊃C60/70)+⋅/−⋅ type are observed for the first time as isolated solitary gas‐phase species. Here, C60‐based [2 : 1] complexes are less stable than the respective C70 analogues. By virtue of the high stability of cationic [1 : 1] complexes, [2 : 1] complexes show a strongly reduced stability of the radical cations. DFT analyses of the minimum geometries as well as molecular dynamics calculations support the experimental data. Furthermore, our novel gas‐phase [2 : 1] complexes are also found in 1,2‐dichlorobenzene. Insights into the thermodynamic parameters of the binding process as well as the species distribution are derived from isothermal titration calorimetry (ITC) measurements.

Herein we report the synthesis of covalently functionalized carbon nano-onions (CNOs) via a reductive approach using unprecedented alkali-metal CNO intercalation compounds. For the first time, an in situ Raman study of the controlled intercalation process with potassium has been carried out revealing a Fano resonance in highly doped CNOs. The intercalation was further confirmed by electron energy loss spectroscopy and X-ray diffraction. Moreover, the experimental results have been rationalized with DFT calculations. Covalently functionalized CNO derivatives were synthesized by using phenyl iodide and n-hexyl iodide as electrophiles in model nucleophilic substitution reactions. The functionalized CNOs were exhaustively characterized by statistical Raman spectroscopy, thermogravimetric analysis coupled with gas chromatography and mass spectrometry, dynamic light scattering, UV-vis, and ATR-FTIR spectroscopies. This work provides important insights into the understanding of the basic principles of reductive CNOs functionalization and will pave the way for the use of CNOs in a wide range of potential applications, such as energy storage, photovoltaics, or molecular electronics.

Cyclophanes of different ring sizes featuring perylene-3,4:9,10-tetracarboxylic acid bisimide (PBI) linked by flexible malonates were designed, synthesized, and investigated with respect to their structural, chemical and photo-physical properties. It is predominantly the number of PBIs and their geometric arrangement, which influence dramatically their properties. For example, two-PBI containing cyclophanes reveal physico-chemical characteristics that are governed by strong co-facial π–π interactions. This is in stark contrast to cyclophanes with either three or four PBIs. Key to co-facial π–π stackings are the flexible malonate linkers, which, in turn, set up the ways and means for diastereoselectivity of the homochiral PBIs at low temperatures, on one hand. In terms of selectivity, diastereomeric (M,M)/(P,P) : (M,P)/(P,M) pairs with a ratio of approximately 10 : 1 are discernible in the 1H NMR spectra in C2D2Cl4 and a complete diastereomeric excess is found in CD2Cl2. On the other hand, symmetry-breaking charge transfer as well as charge separation at room temperature are corroborated in steady-state and time-resolved photo-physical investigations. Less favourable are co-facial π–π stackings in the three-PBI containing cyclophanes. For statistical reasons, the diastereoisomers (M,M,M)/(P,P,P) and (M,M,P)/(P,P,M) occur here in a ratio of 1 : 3. In this case, symmetry-breaking charge transfer as well as charge separation are both slowed down. The work was rounded-off by integrating next to the PBIs, for the first time, hydrophobic or hydrophilic fullerenes into the resulting cyclophanes. Our novel fullerene–PBI cyclophanes reveal unprecedented diastereoselective formation of homochiral (M,M)/(P,P) pairs exceeding the traditional host–guest approach. Hybridization with fullerenes allows us to modulate the resulting solubility, stacking, cavity and chirality, which is of tremendous interest in the field., Perylene bisimide (PBI) cyclophanes linked by flexible malonates were functionalized with fullerenes. Modulation of the chemical environment enhances the chiral self-sorting, leading exclusively to the homochiral diastereomeric pair (M,M)/(P,P).

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.

Unprecedented synthesis of a fullerene dumbbell consisting of an endohedral metallic Sc3N@C80 and an empty C60 fullerene which reveals an exceptional electronic behaviour.

Herein, the synthesis of fullerene derivatives with adjustable polarities and lyotropic aggregation properties is reported. The polarity range spans from superhydrophobic to hydrophilic, while simultaneously providing a further reactive position with a view to graft them onto other materials. The synthetic strategy relies on a selective protection with an isoxazoline moiety. The remaining octahedral positions were further functionalized with the desired groups to tune their solubility, yielding mixed [5:1] hexakisadducts. The subsequent deprotection by clean photolytic reaction led to fullerene pentakisadducts with an incomplete octahedral addition pattern, which are useful forerunners for the synthesis of building blocks. Their hydrophobic/hydrophilic behavior has been characterized both in solution and surface through octanol/water partition coefficients (log P) and contact angle measurements. Furthermore, these derivatives can form supramolecular constructions which have been studied by dynamic light scattering (DLS) and cryo‐TEM.

An unprecedented hybrid dumbbell consisting of a metallofullerene and an empty fullerene was afforded via simple click reaction of suitable precursor derivatives of Sc

A general procedure for the assembly of hetero-bifunctional cubic silsesquioxanes with diverse functionality and a perfectly controlled distribution of functional groups on the inorganic framework has been developed. The method is based on a two-step sequence of mono- and hepta-functionalization through the ligand-accelerated copper(I)-catalyzed azide-alkyne cycloaddition of a readily available octaazido cubic silsesquioxane. The stoichiometry of the reactants and the law of binomial distribution essentially determine the selectivity of the key monofunctionalization reaction when a copper catalyst with strong donor ligands is used. The methodology has been applied to the preparation of a set of bifunctional nano-building-blocks with orthogonal reactivity for the controlled assembly of precisely defined hybrid nanomaterials and a fluorescent multivalent probe for application in targeted cell-imaging. The inorganic cage provides an improved photostability to the covalently attached dye as well as a convenient framework for the 3D multivalent display of the pendant epitopes. Thus, fluorescent bioprobes based on well-defined cubic silsesquioxanes offer interesting advantages over more conventional fully organic analogues and ill-defined hybrid nanoparticles and promise to become powerful tools for the study of cell biology and for biomedical applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The preparation of the first structurally well-defined Janus nanocube showing two chemically distinct opposed faces is described. The synthetic approach is based on a highly efficient and symmetrycontrolled CuAAC functionalization of an octa-azido cubic silsesquioxane with a conformationally constrained tetra-alkyne with an appropriate spatial orientation of the triple bonds., with two sets of orthogonally reactive functional groups. We gratefully acknowledge financial support by the Spanish Ministerio de Ciencia e Innovación (project MAT2010-20646- C04-03) and Ministerio de Economía y Competitividad (project MAT2014-51937-C3-1-P). We also acknowledge the Spanish Ministerio de Economía y Competitividad for a FPI contract to A. B., and CSIC for a JAEDOC contract to J. R. S. and a JAEPRE contract to M. E. P.-O., and for support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

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.

9 páginas, 1 figura, 1 esquema, 2 tablas, A one-step synthesis of octakis(3-azidopropyl)octasilsesquioxane from commercially available octakis(3-aminopropyl)octasilsesquioxane has been developed through a highly efficient diazo-transfer reaction under very mild conditions. Nonaflyl azide is shown to be a safer, cheaper, and more efficient reagent for this transformation than the better known and generally used diazo-transfer reagent triflyl azide. Octakis(3-azidopropyl)octasilsesquioxane is an excellent nanobuilding block that can be readily octafunctionalized with a range of terminal alkynes by copper(I)-catalyzed 1,3-dipolar azide–alkyne cycloaddition to provide new functional nanocages, maintaining a perfect 3D cubic symmetry. The mildness, simplicity, and efficiency of this approach have been demonstrated in the preparation of a glyco-polyhedral oligosilsesquioxane (POSS) conjugate and a BODIPY–POSS cluster (BODIPY=boron dipyrromethene)., We thank the Ministry of Education and Science of Spain for financial support (projects CTQ-2006–15515-C02–02/BQU and MAT-2007-65778- C02-01) and for a FPU predoctoral fellowship to B.T.

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.

Polyhedral oligosilsesquioxanes (POSS) have recently attracted attention as scaffolds for the synthesis of multivalent bioconjugates. The synthesis of glycosyl-octasilsesquioxanes (glyco-POSS) using a copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition approach is reported. The problems associated with the use of bases or aqueous media in their preparation are investigated and a comprehensive study of the multivalent interaction between the mannosyl-octasilsesquioxanes and a model lectin, concanavalin A (Con A), using an array of complementary biophysical techniques is presented. The possibility to modulate the half-life of POSS conjugates in aqueous solution and the low toxicity of their constituent monomeric organosilanes offers an advantage over other scaffolds in vivo, preventing bioaccumulation and saturation of complementary receptors (lectins). Despite the hydrolysis in water, the octamannosyl-POSS studied shows a 50-fold higher binding affinity to Con A than methyl α-D-mannopyranoside. These experiments suggest that the novel glyco-POSS are attractive compounds for in vivo applications that require multivalent display of glycans., The authors thank the Spanish Ministerio de Ciencia e Innovación (projects CTQ-2006-15515-C02-02/BQU, CTQ2009-14551-C02-02, MAT2010-20646-C04-03, SAF2010-15670, and CTQ2010-15848), the Comunidad de Madrid (project S2009/PPQ-1634 “AVANCAT”), the Junta de Andalucía, and the European Union (FEDER and FSE) for fi nancial support. The authors also thank Ministerio de Ciencia e Innovación for FPU predoctoral contracts to B.T. and A.M.-A., and C.S.I.C. for a JAEPREDOC contract to M.E.P.-O.

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.

New hybrid organic–inorganic dyes based on an azide-functionalized cubic octasilsesquioxane (POSS) as the inorganic part and a 4,4-difluoro- 4-bora-3a,4a-diaza-s-indacene (BDP) chromophore as the organic component have been synthesized by copper(I)-catalyzed 1,3-dipolar cycloaddition of azides to alkynes. We have studied the effects of the linkage group of BDP to the POSS unit and the degree of functionalization of this inorganic core on the ensuing optical properties by comparison with model dyes. The high fluorescence of the BDP dye is preserved in spite of the linked chain at its meso position, even after attaching one BDP moiety to the POSS core. The laser action of the new dyes has been analyzed under transversal pumping at 532 nm in both the liquid phase and when incorporated into solid polymeric matrices. The monosubstituted new hybrid dye exhibits high lasing efficiency of up to 56% with high photostability, with its laser output remaining at the initial value after 4 105 pump pulses in the same position of the sample at a repetition rate of 30 Hz. However, functionalization of the POSS core with eight fluorophores leads to dye aggregation, as quantum mechanical simulation has revealed, worsening the optical properties and extinguishing the laser action. The new hybrid systems based on dye-linked POSS nanoparticles open up the possibility of using these new photonic materials as alternative sources for optoelectronic devices, competing with dendronized or grafted polymers, We thank the Spanish Ministerio de Ciencia e Innovaci n (projects MAT2007-65778-C02-01, MAT2007-65778-C02–02, TRACE2009-0144, CTQ-2006-15515-C02, CTQ2009-14551-C02-02, MAT2010-20646-C04-01, MAT2010-20646-C04-03, and MAT2010-20646-C04-04), the Comunidad de Madrid (project S2009/PPQ-1634 “AVANCAT”), and Gobierno Vasco (IT339-10) for financial support. We also thank the Ministerio de Ciencia e Innovaci n for an FPU predoctoral fellowship to B.T. and the C.S.I.C. for a JAE-PREDOC fellowship to M.E.P.-O. The SGI/IZO-SGIker UPV/ EHU is gratefully thanked for allocation of computational resources.

The title reagent is also successfully applied to the one-pot regioselective synthesis of 1,2,3-triazoles by a subsequent inter- or intramolecular azide—alkyne 1,3-dipolar cycloaddition reaction.

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.

6 páginas, 2 esquemas, 2 tablas, Nonafluorobutanesulfonyl azide is an efficient, shelf-stable and cost-effective diazo transfer reagent for the synthesis of azides from primary amines. The reagent can also be successfully applied to the one-pot regioselective synthesis of 1,2,3-triazoles from primary amines by a sequential diazo transfer and azide–alkyne 1,3-dipolar cycloaddition process catalyzed by copper. The cycloaddition step can be conducted in an inter- or intramolecular way to afford 1,4- or 1,5-disubstituted triazoles, respectively. The atypical 1,5-regioselectivity under copper catalysis is a consequence of geometrical constraints of the amino-alkyne substrates used in the intramolecular version. Nonafluorobutanesulfonyl azide offers an advantageous alternative to the better known and most commonly used trifluoromethanesulfonyl azide., We thank the Spanish Ministerio de Ciencia e Innovación (projects CTQ-2006-15515-C02-02/BQU and CTQ2009- 14551-C02-02) and Comunidad de Madrid (project S2009/ PPQ-1634 “AVANCAT”) for financial support. We also thank Ministerio de Ciencia e Innovación for a FPU predoctoral fellowship to B. T. and C.S.I.C. for a JAE-Doc contract to J. R. S., a JAE-Predoc fellowship to M. E. P.-O., and a JAE-Intro fellowship to R. M.-B.

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.