Publications > Sánchez-Pavón et al

Dyes Pigm. 2022, 205, 110323.

Highly efficient unbridged D-A+(D) chromophores based on the quinolizinium cation for nonlinear optical (NLO) applications.

Esmeralda Sánchez-Pavón, Javier Recio, Marco Antonio Ramirez, Belen Batanero, Koen Clays, Francisco Mendicuti, Gema Marcelo, Thais Carmona, Obis Castaño, Silvia Angelova, Jose L. Andres, Juan J. Vaquero, Ana M. Cuadro

Palabras clave: Quinolizinium cation; D-A(D) unbridged chromophores; Nonlinear optical application; First hyperpolarizability

Resumen

Novel charged D-A+ chromophores based on quinolizinium cations as acceptor unit have been prepared by treating haloquinolizinium salts with N-heteroarylstannanes under Stille reaction conditions. This approach provides an easy access to potential one-dimensional D-A+ and two-dimensional D-A+-D chromophores in which the acceptor moiety (A+) is the simple azonia cation and the donors are different π-rich N-heterocycles. The first hyperpolarizabilities (β) were measured by hyper-Rayleigh scattering experiments and the experimental data confirmed that the inherent polarization between donor and acceptor fragments modulates the NLO properties. The electronic structures and properties (including both the linear and nonlinear optical properties) of the quinolizinium chromophores were examined by theoretical (DFT, HF and MP2) calculations. A promising strategy for the rational design of D-A building blocks to create new organic-based NLO materials is proposed.

Publications > Mariz et al

2021; 4(1):142.

Two-photon activated precision molecular photosensitizer targeting mitochondria.

Inês F. A. Mariz, Sandra N. Pinto, Ana M. Santiago, José M. G. Martinho, Javier Recio, Juan J. Vaquero, Ana M. Cuadro, Ermelinda Maçôas

Resumen

Mitochondria metabolism is an emergent target for the development of novel anticancer agents. It is amply recognized that strategies that allow for modulation of mitochondrial function in specific cell populations need to be developed for the therapeutic potential of mitochondria-targeting agents to become a reality in the clinic. In this work, we report dipolar and quadrupolar quinolizinium and benzimidazolium cations that show mitochondria targeting ability and localized light-induced mitochondria damage in live animal cells. Some of the dyes induce a very efficient disruption of mitochondrial potential and subsequent cell death under two-photon excitation in the Near-infrared (NIR) opening up possible applications of azonia/azolium aromatic heterocycles as precision photosensitizers. The dipolar compounds could be excited in the NIR due to a high two-photon brightness while exhibiting emission in the red part of the visible spectra (600–700 nm). Interaction with the mitochondria leads to an unexpected blue-shift of the emission of the far-red emitting compounds, which we assign to emission from the locally excited state. Interaction and possibly aggregation at the mitochondria prevents access to the intramolecular charge transfer state responsible for far-red emission.

Publications > Bosch et al

Dyes and Pigments. 2021 Aug 1; :109443.

A new family of fluorescent pyridazinobenzimidazolium cations with DNA binding properties.

Pedro Bosch¹, Gema Marcelo², Alejandra Matamoros-Recio³, David Sucunza⁴, Francisco Mendicuti², Alberto Domingo³, Juan J Vaquero⁴

1. Departamento de Química Orgánica y Química Inorgánica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.  2. Departamento de Química Analítica, Química Física e Ingeniería Química, 28805, Alcalá de Henares, Madrid, Spain.  3. Departamento de Biología de Sistemas, Instituto de Investigación Química “Andrés M. Del Río” (IQAR), Universidad de Alcalá, IRYCIS, 28805, Alcalá de Henares, Madrid, Spain.  4. Departamento de Química Orgánica y Química Inorgánica, 28805, Alcalá de Henares, Madrid, Spain.

Abstract

A series of novel azonia aromatic heterocycles formed by a pyridazinobenzimidazolium system has been synthesized. Spectrofluorimetric and circular dichroism measurements, as well as theoretical simulations for these materials, have shown their interesting fluorescence properties and DNA-binding ability. Stoichiometries and binding constants were obtained by fluorescence and the induced circular dichroism spectra analysis. Moreover, the potential of these compounds for cell staining has been investigated in living HeLa cells by confocal microscopy imaging.

Publications > Garre et al

J Org Chem. 2020, 85, 441 PubMed 31858801

Synthesis and Photophysical Behavior of a Highly Fluorescent Family of Unsymmetrical Organoboron Complexes Containing 5-(Pyridin-2-ylmethylene)imidazolidine-2,4-dione Moieties.

M Soledad Garre¹, Raul Losantos², Sara Gutierrez¹, David Sucunza¹, Patricia Garcia-Garcia¹, Diego Sampedro², Juan J Vaquero¹

1. Departamento de Quimica Organica y Quimica Inorganica, Instituto de Investigacion Quimica "Andres M. del Rio" (IQAR) , Universidad de Alcala, IRYCIS , 28805 Alcala de Henares , Spain.  2. Departamento de Quimica, Centro de Investigacion en Sintesis Quimica (CISQ) , Universidad de La Rioja , Madre de Dios 53 , 26006 Logrono , Spain.

Abstract

A new and highly fluorescent family of unsymmetrical organoboron complexes containing 5-(pyridin-2-ylmethylene)imidazolidine-2,4-dione moieties has been synthesized in three steps. These compounds show strong absorptions covering a wide range of the UV-vis spectrum and are strongly emissive (varphif of up to 0.92 in CH3CN). Moreover, two fluorophores that include an alkyne or an azide group at the end of the alkyl chain and with potential utility in bioorthogonal chemistry have been developed. One of these, in which the glycol substituent provides an enhanced water solubility without compromising the fluorescence (varphif = 0.85 in water), may be of particular importance.

Publications > Bosch et al

Org. Chem. Front. 2018, 5, 1916

Dibenzopyridoimidazocinnolinium cations: a new family of light-up fluorescent DNA probes.

Pedro Bosch¹, David Sucunza¹, Francisco Mendicuti², Alberto Domingo³, Juan J Vaquero¹

1. Departamento de Quimica Organica y Quimica Inorganica, Instituto de Investigacion Quimica "Andres M. del Rio" (IQAR) , Universidad de Alcala , 28805 Alcala de Henares , Spain.  2. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, Spain.  3. Departamento de Biología de Sistemas, Universidad de Alcalá, Spain.

Abstract

Steady-state and time-resolved fluorescence, circular dichroism and molecular modelling techniques have been applied to a new family of weakly fluorescent dibenzopyridoimidazocinnolinium derivatives whose fluorescence intensity increases significantly (larger than × 3.5) upon DNA addition. The synthesis of these azonia cations, which bind to DNA by intercalation, was carried out using a Westphal condensation and a Suzuki cross coupling reaction as key steps. A live-cell staining analysis by confocal microscopy imaging was also performed and showed the capacity of these new compounds for active uptake and accumulation by living cells, with complex patterns of intracellular distribution observed.

Publications > Cañeque et al

Dyes Pigm. 2017, 144, 17

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

Tatiana Cañeque¹, Ana M. Cuadro¹, Raúl Custodio¹, Julio Alvarez-Builla¹, Belén Batanero¹, Pilar Gómez-Sal¹, Javier Pérez-Moreno², Koen Clays³, Obis Castaño⁴, José L. Andrés⁴, Thais Carmona⁴, Francisco Mendicuti⁴, Juan J Vaquero¹

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.

Publications > Bosch et al

Dyes Pigm. 2017, 138, 135

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

Pedro Bosch¹, Verónica García², Başak S. Bilen³, David Sucunza¹, Alberto Domingo², Francisco Mendicuti³, Juan J Vaquero¹

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.

Publications > Zacharioudakis et al

Biorg. Med. Chem. Lett. 2017, 27, 203

Quinolizinium as a new fluorescent lysosomotropic probe.

Emmanouil Zacharioudakis¹, Tatiana Cañeque², Raúl Custodio³, Sebastian Müller¹, Ana M. Cuadro², Juan J Vaquero², Raphaël Rodriguez¹

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.

Publications > Gutierrez et al

Chem. Eur. J. 2015, 21, 18758 PubMed 26525155

Highly Fluorescent Green Fluorescent Protein Chromophore Analogues Made by Decorating the Imidazolone Ring.

Sara Gutierrez¹, David Martinez-Lopez², Maria Moron¹, David Sucunza^1, a, Diego Sampedro^2, a, Alberto Domingo³, Antonio Salgado⁴, Juan J Vaquero^1, a

1. Departamento de Quimica Organica y Quimica Inorganica, Universidad de Alcala, Edificio de Farmacia, 28871, Alcala de Henares, Madrid (Spain).  2. Departamento de Quimica, Centro de Investigacion en Sintesis Quimica (CISQ), Universidad de La Rioja, Madre de Dios, 53, 26006, Logrono, La Rioja (Spain).  3. Departamento de Biologia de Sistemas, Universidad de Alcala, Edificio de Medicina, 28871, Alcala de Henares, Madrid (Spain).  4. Departamento de Quimica, Universidad Yachay Tech, Hacienda San Jose s/n, San Miguel de Urcuqui, 100119 (Ecuador).

a. david.sucunza@uah.es  a. diego.sampedro@unirioja.es  a. juanjose.vaquero@uah.es

Keywords: TD-DFT calculations; cell staining; fluorescence; imidazolone derivatives; proteins

Abstract

The synthesis and photophysical behavior of an unexplored family of green fluorescent protein (GFP)-like chromophore analogues is reported. The compound (Z)-4-(4-hydroxybenzylidene)-1-propyl-2-(propylamino)-1H-imidazol-5(4 H)-one (p-HBDNI, 2 a) exhibits significantly enhanced fluorescence properties relative to the parent compound (Z)-5-(4-hydroxybenzylidene)-2,3-dimethyl-3,5-dihydro-4H-imidazol-4-one (p-HBDI, 1). p-HBDNI was considered as a model system and the photophysical properties of other novel 2-amino-3,5-dihydro-4H-imidazol-4-one derivatives were evaluated. Time-dependent DFT calculations were carried out to rationalize the results. The analogue AIDNI (2 c), in which the 4-hydroxybenzyl group of p-HBDNI was replaced by an azaindole group, showed improved photophysical properties and potential for cell staining. The uptake and intracellular distribution of 2 c in living cells was investigated by confocal microscopy imaging.

Publications > Marcelo et al

J. Phys. Chem. A 2015, 119, 11, 2351

Nonlinear Emission of Quinolizinium Based Dyes With Application in Fluorescence Lifetime Imaging.

Gema Marcelo¹, Sandra Pinto¹, Tatiana Cañeque², Inês F. A. Mariz¹, Ana M. Cuadro², Juan J Vaquero², José M. G. Martinho¹, Ermelinda M. S. Maçôas¹

1. Centro de Química-Física Molecular (CQFM) and Institute of Nanoscience and Nanotechnology (IN), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal.  2. Departamento de Química Orgánica y Química Inorganica, Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.

Abstract

Charged molecules based on the quinolizinum cation have potential applications as labels in fluorescence imaging in biological media under nonlinear excitation. A systematic study of the linear and nonlinear photophysics of derivatives of the quinolizinum cation substituted by either dimethylaniline or methoxyphenyl electron donors is performed. The effects of donor strength, conjugation length, and symmetry in the two-photon emission efficiency are analyzed in detail. The best performing nonlinear fluorophore, with two-photon absorption cross sections of 1140 GM and an emission quantum yield of 0.22, is characterized by a symmetric D-π-A%@2B-π-D architecture based on the methoxyphenyl substituent. Application of this molecule as a fluorescent marker in optical microscopy of living cells revealed that, under favorable conditions, the fluorophore can be localized in the cytoplasmatic compartment of the cell, staining vesicular shape organelles. At higher dye concentrations and longer staining times, the fluorophore can also penetrate into the nucleus. The nonlinearly excited fluorescence lifetime imaging shows that the fluorophore lifetime is sensitive to its location in the different cell compartments. Using fluorescence lifetime microscopy, a multicolor map of the cell is drafted with a single dye.