Category Archives: 2017

Cañeque et al. Dyes and Pigments. 2017;:17-31. Azonia aromatic heterocycles as a new acceptor unit in D-π-A%@2B vs D-A%@2B nonlinear optical chromophores.

Publications > Cañeque et al

Azonia aromatic heterocycles as a new acceptor unit in D-π-A%@2B vs D-A%@2B nonlinear optical chromophores.

1. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  2. Department of Physics, Skidmore College, Saratoga Springs, NY, United States.  3. Department of Chemistry, University of Leuven, Celestijnenlaan 200 D, 3001, Leuven, Belgium.  4. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.

Abstract

A comparison of D-π-A%@2B and D-A%@2B cationic chromophores based on the quinolizinium system as new acceptor units is reported along with the results of studies into their linear and non-linear optical properties and electrochemical data. Experimental and theoretical data show that quinolizinium-based chromophores may provide a new generation of second-order non-linear materials with enhanced performance. The first hyperpolarizabilities were measured by Hyper-Rayleigh scattering experiments and the experimental data are supported by a theoretical analysis. In some chromophores the absence of a bridge (D-A%@2B) between the donor and acceptor fragments enhances the NLO properties and the single crystal structure of such a material has been determined by X-ray diffraction.

Martín et al. Journal of Analytical and Applied Pyrolysis. 2017;:278-285. Microwave-assisted pyrolysis of Mediterranean forest biomass waste: Bioproduct characterization.

Publications > Martín et al

Microwave-assisted pyrolysis of Mediterranean forest biomass waste: Bioproduct characterization.

1. Cátedra de Medio Ambiente, Facultad de Biología, Universidad de Alcalá, 28871-Alcalá de Henares, Madrid, Spain.  2. Centro de Química Aplicada y Biotecnología, Universidad de Alcalá, 28871-Alcalá de Henares, Madrid, Spain.  3. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871-Alcalá de Henares, Madrid, Spain.

Abstract

Different types of forest and scrub biomass waste that are representative of the Mediterranean biogeographical region (Pinus pinaster, Quercus ilex, waste from forestry activities in pinewoods and Cistus ladanifer) were pyrolyzed in a batch microwave reactor. The pyrolysis conditions were optimized using Pinus pinaster as the raw material. All experiments were performed at 400W with 7.5% biochar as a microwave absorber. Under these conditions four fractions were characterized: a non-condensable gas fraction, a bio-liquid composed of separable organic and aqueous soluble components and biochar. All liquid and gas fractions were characterized by gas chromatography/mass spectrometery (GC/qMS) to identify the main components. The bioliquid organic fraction was distilled and a bio-bitumen residue was collected. The rheological properties of this residue were studied. Biochar was characterized by measuring the specific surface area in order to assess its adsorptive properties. Mass distribution was calculated according to the feedstock.

Abengozar et al. Org Lett. 2017;19(13):3458-3461. Synthesis, Optical Properties, and Regioselective Functionalization of 4a-Aza-10a-boraphenanthrene.

Publications > Abengozar et al

Synthesis, Optical Properties, and Regioselective Functionalization of 4a-Aza-10a-boraphenanthrene.

1. Departamento de Quimica Organica y Quimica Inorganica, Universidad de Alcala , 28871 Alcala de Henares, Madrid, Spain.  2. Departamento de Quimica Analitica, Quimica Fisica e Ingenieria Quimica, Universidad de Alcala , 28871 Alcala de Henares, Madrid, Spain.  3. Departamento de Quimica, Centro de Investigacion en Sintesis Quimica (CISQ), Universidad de La Rioja , Madre de Dios 53, 26006 Logrono, Spain.

Abstract

4a-Aza-10a-boraphenanthrene has been synthesized in only four steps from commercially available materials with a remarkable overall yield of 62%. In contrast to other BN-isosteres of phenathrene, this isomer is weakly fluorescent, which has been explained by means of computational studies that found a low energy conical intersection for the nonradiative deactivation of the excited state. Moreover, a completely regioselective functionalization of 4a-aza-10a-boraphenanthrene at C-1 by reaction with activated electrophiles has been achieved.

Bosch et al. Dyes and Pigments. 2017;:135-146. Imidazopyridinium cations: A new family of azonia aromatic heterocycles with applications as DNA intercalators.

Publications > Bosch et al

Imidazopyridinium cations: A new family of azonia aromatic heterocycles with applications as DNA intercalators.

1. Departamento de Química Inorgánica y Química Orgánica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  2. Departamento de Biología de Sistemas, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  3. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.

Abstract

Two novel imidazopyridinium cations formed by a hexacyclic azonia aromatic system have been synthesized. Spectrofluorimetric titrations, circular dichroism measurements, theoretical simulations and fluorescence-based thermal denaturation experiments on these materials have shown the interesting fluorescence properties and DNA-binding ability by intercalation, with a marked preference for AT-rich sequences. Compound 2 presents the highest fluorescence quantum yield (0.32 in 5% DMSO/water and 0.46 in MeOH) and affinity for DNA (binding constant of ∼4.5 × 105 M−1). Moreover, the potential of these compounds for cell staining has been investigated in living HeLa cells by confocal microscopy imaging. This analysis showed the remarkable capacity of both compounds for uptake and accumulation by living cells.

Zacharioudakis et al. Biorg. Med. Chem. Lett.. 2017;:203-207. Quinolizinium as a new fluorescent lysosomotropic probe.

Publications > Zacharioudakis et al

Quinolizinium as a new fluorescent lysosomotropic probe.

1. Institut Curie, PSL Research University, Organic Synthesis and Cell Biology Group, 26 rue d’Ulm, 75248 Paris Cedex 05, France, CNRS UMR3666, 75005 Paris, France, INSERM U1143, 75005 Paris, France.  2. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  3. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.

Abstract

We have synthesized a collection of quinolizinium fluorescent dyes for the purpose of cell imaging. Preliminary biological studies in human U2OS osteosarcoma cancer cells have shown that different functional groups appended to the cationic quinolizinium scaffold efficiently modulate photophysical properties but also cellular distribution. While quinolizinium probes are known nuclear staining reagents, we have identified a particular quinolizinium derivative salt that targets the lysosomal compartment. This finding raises the question of predictability of specific organelle targeting from structural features of small molecules.

Vasilev et al. Beilstein J Org Chem. 2017;13:2902-2914. Halogen-containing thiazole orange analogues – new fluorogenic DNA stains.

Publications > Vasilev et al

Halogen-containing thiazole orange analogues - new fluorogenic DNA stains.

1. Department of Pharmaceutical and Applied Organic Chemistry, Faculty of Chemistry and Pharmacy, Sofia University "St. Kliment Ohridski", 1 James Bourchier Blvd., 1164 Sofia, Bulgaria.  2. Department of Organic Chemistry and Pharmacognosy, Faculty of Chemistry and Pharmacy, Sofia University "St. Kliment Ohridski", 1 James Bourchier Blvd., 1164 Sofia, Bulgaria.  3. Departments of Organic and Physical Chemistry, University of Alcala, 28871-Alcala de Henares, Madrid, Spain.  4. Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.

Abstract

Novel asymmetric monomeric monomethine cyanine dyes 5a-d, which are analogues of the commercial dsDNA fluorescence binder thiazole orange (TO), have been synthesized. The synthesis was achieved by using a simple, efficient and environmetally benign synthetic procedure to obtain these cationic dyes in good to excellent yields. Interactions of the new derivatives of TO with dsDNA have been investigated by absorption and fluorescence spectroscopy. The longest wavelength absorption bands in the UV-vis spectra of the target compounds are in the range of 509-519 nm and these are characterized by high molar absorptivities (63000-91480 L.mol(-1).cm(-1)). All investigated dyes from the series are either not fluorescent or their fluorescence is quite low, but they become strongly fluorescent after binding to dsDNA. The influence of the substituents attached to the chromophores was investigated by combination of spectroscopic (UV-vis and fluorescence spectroscopy) and theoretical (DFT and TDDFT calculations) methods.