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1.
Chem Commun (Camb) ; 56(53): 7341-7344, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32483566

RESUMO

In this communication, electrostatically assembled phthalocyanine (Pc)-DNA origami (DO) complexes are formed and their optical properties are demonstrated. The formation of the complex prevents the Pc aggregation, thus yielding an enhanced optical response and photooxidative resilience towards aggregation in biologically relevant media. Simultaneously, the Pc protects the DO against enzymatic digestion. Both features solve previous drawbacks associated with phthalocyanine photosensitizers and DNA nanocarriers. The studied complexes may find use in technologies related to the photogeneration of singlet oxygen, e.g., photocatalysis, diagnositic arrays and photodynamic therapy.

2.
Chemistry ; 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32293078

RESUMO

Owing to the electron donating and accepting nature of corroles (Corr) and phthalocyanines (Pc), respectively, we designed and developed two novel covalently linked Corr-Pc conjugates. The synthetic route allows the preparation of the target conjugates in satisfying yields. Comprehensive steady-state absorption, fluorescence, and electrochemical assays enabled insights onto energy and electron transfer processes upon photoexcitation. Coordinating a pyridine-appended subphthalocyanine (SubPc) to the Pc of the conjugate sets up the ways and means to realize the first example of an array composed by three different porphyrinoids, which drives a cascade of energy and charge transfer processes occur. Importantly, the SubPc assists in stabilizing the charge-separated state, that is, one-electron oxidized Corr and the one electron reduced Pc, upon photoexcitation by means of a reductive charge transfer to the SubPc. To the best of our knowledge, this is the first case of an intramolecular oxidation of a Corr within electron donor-acceptor conjugates by means of just photoexcitation. Moreover, the combination of Corr, Pc, and SubPc guarantees panchromatic absorption across the visible range of the solar spectrum, with the SubPc covering the "green gap" that usually affects porphyrinoids.

3.
J Am Chem Soc ; 142(17): 7920-7929, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32243157

RESUMO

We report here the synthesis of two novel subporphyrins (SubPs), in which the macrocycle has been functionalized at its meso (1) or axial (2) position with tetracyanobuta-1,3-diene (TCBD)-aniline. In-depth spectroscopic, spectrometric, and electrochemical analyses were carried out with both of them, whose molecular structures were determined by single-crystal X-ray diffraction studies. In the case of 2, its Ra and Sa enantiomers were separable by chiral HPLC and presented a fairly good configurational stability at room temperature, which enabled determining the activation parameters for the thermally induced racemization. Conversely, the enantiomers' separation was unfeasible for 1 due to the conformational and/or configurational dynamics of the TCBD-aniline, a structural "flexibility" that could be drastically reduced at low temperatures. The physicochemical impact of placing the TCBD-aniline at either the axial or peripheral positions of SubPs is also rather significant. The HOMO-LUMO gap is reduced by as much as 0.35 eV in SubP-(TCBD-aniline)meso 1 (1.77 eV) and, in turn, enables an emissive charge-transfer (CT) state in virtually all environments. It is only in polar environments, where it links a local excitation with an indirect charge separation. In contrast, a much larger HOMO-LUMO gap of 2.12 eV in SubP-(TCBD-aniline)axial 2 disables an emissive CT state and enforces either an exciplex deactivation in apolar environments or a direct charge separation in polar environments.

4.
Molecules ; 25(7)2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32272726

RESUMO

An asymmetrical, push-pull phthalocyanine bearing bulky tert-butylcarbazolyl moieties as electron donor and carboxylic acid as anchoring group was synthetized and tested as a photosensitizer in dye-sensitized solar cells (DSSC). The new photosensitizer was characterized by 1H and 13C NMR, UV-Vis and mass spectrometry. The bulky tert-butylcarbazolyl moieties avoid the aggregation of the phthalocyanine dye. DFT studies indicate that the HOMO is delocalized throughout the -electron system of the substituted phthalocyanine and the LUMO is located on the core of the molecule with a sizable electron density distribution on carboxyl groups. The new dye has been used as a photosensitizer in transparent and opaque dye-sensitized solar cells, which exhibit poor efficiencies related to a low Jsc.

5.
Molecules ; 25(1)2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31947934

RESUMO

We have previously demonstrated that singlet oxygen photosensitization abilities of Zn(II) phthalocyanines (Zn(II)Pcs) are enhanced through α-functionalization with bulky fluorinated substituents (i.e., bis(trifluoromethyl)phenyl units) at facing positions of ABAB Zn(II)Pcs, where A and B refer to differently functionalized isoindoles. In this work, we have prepared the Zn(II)Pc ABAB 1 endowed with hydrophilic triethylene glycol monomethyl ether (i.e., at the A isoindoles) to provide solubility in aqueous media, together with its A3B and A4 counterparts, and compared their ability to behave as photosensitizers for photodynamic therapy. All photophysical data, aggregation studies and preliminary in vitro biological assays in cell cultures of SCC-13 (squamous cell carcinoma) and HeLa (cervical cancer cells), have proved ABAB 1 as the best photosensitizer of the series.

6.
Chemistry ; 26(8): 1697, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31922634

RESUMO

Invited for the cover of this issue is the group of Torres at the University of Madrid. The image of the cover of this issue depicts cancer cells being destroyed by reactive singlet oxygen produced by ruthenium phthalocyanine glycoconjugates under red light. The work, developed at the Universities of Madrid, Aveiro, Lisbon and Coimbra, describes ruthenium phthalocyanines as powerful bladder cancer PDT agents. Read the full text of the article at 10.1002/chem.201903546.


Assuntos
Compostos Organometálicos/química , Fármacos Fotossensibilizantes/química , Oxigênio Singlete/metabolismo , Humanos , Compostos Organometálicos/síntese química , Compostos Organometálicos/uso terapêutico , Fotoquimioterapia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/uso terapêutico , Neoplasias da Bexiga Urinária/tratamento farmacológico
7.
Angew Chem Int Ed Engl ; 59(8): 3127-3130, 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-31840378

RESUMO

Peripherally metalated porphyrinoids are promising functional π-systems displaying characteristic optical, electronic, and catalytic properties. In this work, 5-(2-pyridyl)- and 5,10,15-tri(2-pyridyl)-BIII -subporphyrins were prepared and used to produce cyclometalated subporphyrins by reactions with [Cp*IrCl2 ]2 , which proceeded through an efficient C-H activation to give the corresponding mono- and tri-IrIII complexes, respectively. While the mono-IrIII complex was obtained as a diastereomeric mixture, a C3 -symmetric tri-IrIII complex with the three Cp*-units all at the concave side was predominantly obtained in a high yield of 90 %, which displays weak NIR phosphorescence even at room temperature in degassed CH2 Cl2 , differently from the mono-IrIII complexes.

8.
Angew Chem Int Ed Engl ; 59(3): 1334-1339, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31729821

RESUMO

On-surface synthesis offers a versatile approach to prepare novel carbon-based nanostructures that cannot be obtained by conventional solution chemistry. Graphene nanoribbons (GNRs) have potential for a variety of applications. A key issue for their application in molecular electronics is in the fine-tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non-benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) is a highly appealing strategy. Herein we present the selective on-surface synthesis of a Por-GNR hybrid, which consists of two Pors connected by a short GNR segment. The atomically precise structure of the Por-GNR hybrid has been characterized by bond-resolved scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc-AFM). The electronic properties have been investigated by scanning tunneling spectroscopy (STS), in combination with DFT calculations, which reveals a low electronic gap of 0.4 eV.

9.
Chemistry ; 26(7): 1683-1690, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31821617

RESUMO

A [3+3] Schiff-base salphen macrocycle (7 a) was synthesized by imine condensation between ortho-phenylenediamine and ortho-phenylethynyl-bridged bis(5-salicylaldehyde) precursors. The triangular-shaped macrocycle 7 a has a nonclassical (or "inverted") design in which the N2 O2 coordination pockets are located at the sides instead of the corners. Compound 7 a could be synthesized in a reasonably good yield (64 %) considering the steric constraints imposed by the ortho substitution pattern. Subsequent zinc metalation afforded the corresponding Zn metallomacrocycle 7 b. Spectroscopic experiments evidenced weak (7 a) to strong (7 b) self-aggregation behavior in solution. Their ability to self-organize at the supramolecular level was further studied in the solid state by AFM and TEM, which revealed the formation of large bundles of fibers with lengths of several micrometers and widths of nanometers.

10.
Chemistry ; 26(8): 1789-1799, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31605633

RESUMO

The synthesis of ruthenium(II) phthalocyanines (RuPcs) endowed with one carbohydrate unit-that is, glucose, galactose and mannose-and a dimethylsulfoxide (DMSO) ligand at the two axial coordination sites, respectively, is described. Two series of compounds, one unsubstituted at the periphery, and the other one bearing eight PEG chains at the isoindole meta-positions, have been prepared. The presence of the axial DMSO unit significantly increases the phthalocyanine singlet oxygen quantum yields, related to other comparable RuPcs. The compounds have been evaluated for PDT treatment in bladder cancer cells. In vitro studies have revealed high phototoxicity for RuPcs unsubstituted at their periphery. The phototoxicity of PEG-substituted RuPcs has been considerably improved by repeated light irradiation. The choice of the axial carbohydrate introduced little differences in the cellular uptake for both series of photosensitizers, but the phototoxic effects were considerably higher for compounds bearing mannose units.


Assuntos
Compostos Organometálicos/química , Fármacos Fotossensibilizantes/síntese química , Oxigênio Singlete/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Luz , Compostos Organometálicos/síntese química , Compostos Organometálicos/farmacologia , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Espectrofotometria , Bexiga Urinária/efeitos dos fármacos , Bexiga Urinária/metabolismo
11.
J Mater Chem B ; 8(2): 282-289, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31803886

RESUMO

In this paper we describe a straightforward supramolecular strategy to encapsulate silicon phthalocyanine (SiPc) photosensitizers (PS) in polymeric micelles made of poly(ε-caprolactone)-b-methoxypoly(ethylene glycol) (PCL-PEG) block copolymers. While PCL-PEG micelles are promising nanocarriers based on their biocompatibility and biodegradability, the design of our new PS favors their encapsulation. In particular, they combine two axial benzoyl substituents, each of them carrying either three hydrophilic methoxy(triethylenoxy) chains (1), three hydrophobic dodecyloxy chains (3), or both kinds of chains (2). The SiPc derivatives 1 and 2 are therefore amphiphilic, with the SiPc unit contributing to the hydrophobic core, while lipophilicity increases along the series, making it possible to correlate the loading efficacy in PCL-PEG micelles with the hydrophobic/hydrophilic balance of the PS structure. This has led to a new kind of third-generation nano-PS that efficiently photogenerates 1O2, while preliminary in vitro experiments demonstrate an excellent cellular uptake and a promising PDT activity.

12.
J Org Chem ; 85(4): 1948-1960, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31885266

RESUMO

The efficiency of the vinylene moiety as a linker to intercommunicate the subporphyrazine (SubPz) core with other chromophores and redox active systems has been examined. In addition, different substitution patterns for hexaarylated SubPzs have been explored in order to control the absorption, fluorescence, and redox properties independently of one another. Besides X-ray crystallography, complete spectroscopic and electrochemical characterizations have been performed, and the conclusions have been supported by density functional theory calculations. The absorption and emission profiles, as well as the organization of the macrocycles in the crystalline state, are strongly determined by the substitution pattern. Within the hexaarylated family, para-substitution with electron-rich moieties (i.e., phenylene or ether) red-shifts both the SubPz absorption and emission bands. Progressive fading of these effects upon extending the oligophenylene branches from one to three units evidences the less efficient electronic delocalization over the phenyl ends as the oligophenylene branch is enlarged. Contrasting, meta-substitution produces little variation or blue shift of the SubPz Q-band, while bathochromic shifts are always observed for the emission bands. In hexavinylene-SubPzs, peripheral vinylene moieties adopt a coplanar configuration with the aromatic SubPz core, resulting in a π-extended chromophore that preserves the unique electronic tunability of SubPzs. This is reflected by the strong alteration of the SubPz electronic properties produced by phenyl and biphenyl moieties attached to the vinylene ends.

13.
Chem Soc Rev ; 49(4): 1041-1056, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31845688

RESUMO

Phthalocyanines exhibit superior photoproperties that make them a surely attractive class of photosensitisers for photodynamic therapy of cancer. Several derivatives are at various phases of clinical trials, and efforts have been put continuously to improve their photodynamic efficacy. To this end, various strategies have been applied to develop advanced phthalocyanines with optimised photoproperties, dual therapeutic actions, tumour-targeting properties and/or specific activation at tumour sites. The advantageous properties and potential of phthalocyanines as advanced photosensitisers for photodynamic therapy of cancer are highlighted in this tutorial review.


Assuntos
Indóis/uso terapêutico , Neoplasias/tratamento farmacológico , Fármacos Fotossensibilizantes/uso terapêutico , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/uso terapêutico , Humanos , Indóis/química , Luz , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Fotoquimioterapia , Fármacos Fotossensibilizantes/química , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo
14.
Eur J Med Chem ; 187: 111957, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31864170

RESUMO

Herein, we report the synthesis and characterization of new amphiphilic phthalocyanines (Pcs), the study of their singlet oxygen generation capabilities, and biological assays to determine their potential as photosensitizers for photodynamic inactivation of bacteria. In particular, Pcs with an ABAB geometry (where A and B refer to differently substituted isoindole constituents) have been synthesized. These molecules are endowed with bulky bis(trifluoromethylphenyl) groups in two facing isoindoles, which hinder aggregation and favour singlet oxygen generation, and pyridinium or alkylammonium moieties in the other two isoindoles. In particular, two water-soluble Pc derivatives (PS-1 and PS-2) have proved to be efficient in the photoinactivation of S. aureus and E. coli, selected as models of Gram-positive and Gram-negative bacteria.


Assuntos
Antibacterianos/farmacologia , Flúor/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Indóis/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Cátions/química , Cátions/farmacologia , Relação Dose-Resposta a Droga , Flúor/química , Indóis/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Fotoquimioterapia , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Relação Estrutura-Atividade
15.
Nanoscale ; 11(46): 22286-22292, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31730142

RESUMO

A porphyrazine featuring complementary absorption to a pentacene dimer was chosen to fill the absorption gap of the latter in the range of 450 to 600 nm to realize panchromatic absorption through the visible region out to ca. 700 nm. Of even greater relevance is the quantitative intramolecular Förster resonance energy transfer (i-FRET) to funnel energy to the pentacene moieties, where efficient intramolecular singlet fission (i-SF) converts the singlet excited state into the corresponding triplet excited states. Remarkably, the triplet quantum yield either via direct excitation or via indirect i-FRET is up to 200% ± 20% in polar solvents.

16.
Org Lett ; 21(20): 8183-8186, 2019 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-31557041

RESUMO

We describe the preparation of a battery of chiral Zn(II) phthalocyanines with an AABB substitution pattern through cross-condensation of different chiral, binaphthyloxy-linked bisphthalonitriles and (non)functionalized single phthalonitriles. All the compounds are endowed with reactive groups (halogen and/or ethynyl moieties) that will allow us to prepare customized amphiphilic phthalocyanines. Preliminary self-assembly studies in solution have been performed by UV-vis and circular dichroism experiments.

17.
Chemphyschem ; 20(21): 2806-2815, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31471925

RESUMO

A study on electron transfer in three electron donor-acceptor complexes is reported. These architectures consist of a zinc phthalocyanine (ZnPc) as the excited-state electron donor and a fullerene (C60 ) as the ground-state electron acceptor. These complexes are brought together by axial coordination at ZnPc. The key variable in our design is the length of the molecular spacer, namely, oligo-p-phenylenevinylenes. The lack of appreciable ground-state interactions is in accordance with strong excited-state interactions, as inferred from the quenching of ZnPc centered fluorescence and the presence of a short-lived fluorescence component. Full-fledged femtosecond and nanosecond transient absorption spectroscopy assays corroborated that the ZnPc ⋅ + -C60 ⋅ - charge-separated state formation comes at the expense of excited-state interactions following ZnPc photoexcitation. At a first glance, the ZnPc ⋅ + -C60 ⋅ - charge-separated state lifetime increased from 0.4 to 86.6 ns as the electron donor-acceptor separation increased from 8.8 to 29.1 Å. A closer look at the kinetics revealed that the changes in charge-separated state lifetime are tied to a decrease in the electronic coupling element from 132 to 1.2 cm-1 , an increase in the reorganization energy of charge transfer from 0.43 to 0.63 eV, and a large attenuation factor of 0.27 Å-1 .

18.
Adv Mater ; 31(39): e1902582, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31392780

RESUMO

The generation of highly reactive oxygen species (ROS) at room temperature for application in organic synthesis and wastewater treatment represents a great challenge of the current chemical industry. In fact, the development of biodegradable scaffolds to support ROS-generating active sites is an important prerequisite for the production of environmentally benign catalysts. Herein, the electrostatic cocrystallization of a cationic phthalocyanine (Pc) and negatively charged tobacco mosaic virus (TMV) is described, together with the capacity of the resulting crystals to photogenerate ROS. To this end, a novel peripherally crowded zinc Pc (1) is synthesized. With 16 positive charges, this photosensitizer shows no aqueous aggregation, and is able to act as a molecular glue in the unidimensional assembly of TMV. A step-wise decrease of ionic strength in mixtures of both components results in exceptionally long fibers, constituted by hexagonally bundled viruses thoroughly characterized by electron and confocal microscopy. The fibers are able to produce ROS in a proof-of-concept microfluidic device, where they are immobilized and irradiated in several cycles, showing a resilient performance. The bottom-up approach also enables the light-triggered disassembly of fibers after use. This work represents an important example of a biohybrid material with projected application in light-mediated heterogeneous catalysis.

19.
Angew Chem Int Ed Engl ; 58(41): 14644-14652, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31381224

RESUMO

Cyclopenta[hi]aceanthrylenes (CPAs) have been functionalized at two of the peripheral positions with electronically inert trimethylsilylethynyl (1), as well as with electron-donating 4-ethynyl-N,N-dimethylaniline (2), ethynyl ZnII phthalocyanine (3), and ethynyl ZnII porphyrin (4) units. Consistent with X-ray crystal structures of 2 and 4, analyses of absorption and fluorescence of 2-4 point to strong electronic communication between the CPA and the peripheral units, affording quadrupolar electron donor-acceptor-donor charge-transfer conjugates. By virtue of their quadrupolar/dipolar charge-transfer characters in the excited state, 2-4 exhibit fluoro-solvatochromism. Transient absorption spectroscopy confirmed delocalized quadrupolar ground states and formation of weakly solvent stabilized quadrupolar singlet excited states. The latter transform into strongly stabilized dipolar excited states before deactivating to the ground state in 2 and give rise to a fully charge separated state in 3 and 4.

20.
Org Biomol Chem ; 17(32): 7448-7454, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31355402

RESUMO

In-depth, systematic photophysical studies have been performed on a series of ABAB, A3B and A4 ZnPcs functionalized with a varying number of bis(trifluoromethyl)phenyl units (i.e. at the B isoindoles) and other electron-withdrawing/electron-donating moieties (i.e. at the A isoindoles), to determine the influence of the susbtitution pattern on the aggregation features, fluorescence quantum yields and singlet oxygen (1O2) generation abilities of these molecules. As a general trend, the larger the number of bis(trifluoromethyl)phenyl units (i.e.ABAB crosswise functionalized ZnPcs), the lower the fluorescence quantum yield and the higher the 1O2 photosensitization. On the other hand, the electronic character of the substituents at the A isoindoles do not seem to have a clear effect on the photophysical properties of these ABAB ZnPcs. Overall, 1O2 quantum yields determined by the direct observation of the 1O2 phosphorescence are very high, with values ranging from 1 to 0.74 in THF solutions.

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