Papers by Mariette M. Pereira
Mechanochemistry is an alternative for sustainable solvent-free processes that has taken the big ... more Mechanochemistry is an alternative for sustainable solvent-free processes that has taken the big step to become, in the near future, a useful synthetic method for academia and the fine chemical industry. The apparatus available, based on ball milling systems possessing several optimizable variables, requires too many control and optimization experiments to ensure reproducibility, which has limited its widespread utilization so far. Herein, we describe the development of an automatic mechanochemical single-screw device consisting of an electrical motor, a drill, and a drill chamber. The applicability and versatility of the new device are demonstrated by the implementation of di-and multicomponent chemical reactions with high reproducibility, using mechanical action exclusively. As examples, chalcones, dihydropyrimidinones, dihydropyrimidinethiones, pyrazoline, and porphyrins, were synthesized with high yields. The unprecedented sustainability is demonstrated by comparison of EcoScale and E-factor values of these processes with those previously described in the literature.
Research Square (Research Square), May 19, 2023
Background Bio lm in medical devices occurs with bacterial adherence through virulence factors by... more Background Bio lm in medical devices occurs with bacterial adherence through virulence factors by a favorable environment for their proliferation. The transfer of microbial cells from bio lm in endotracheal tube to lungs increases the chances of developing severe infections. This study aimed to optimize antimicrobial photodynamic therapy (PDT) by applying a curcumin-functionalized endotracheal tube in an arti cial respiratory system avoiding bacterial and their dispersion in the respiratory system, adding a mechanical ventilator. Methods This model was built containing three components representing oropharynx, trachea, and lungs. ET-curc was inserted into the system's trachea followed by bio lm formation. Results Microbial migration from Staphylococcus aureus and Methicillin-resistant S. aureus (MRSA) bio lms to the left and right lungs were evaluated with and without mechanical ventilation. PDT was applied to ETcurc using a laser (450nm) and resulted in a total bacterial inactivation, avoiding microbial ow relationships from the upper to the lower air system. The effects indicated high effectiveness in bacterial bio lm inactivation and, consequently, in the prevention of their colonization in lungs. Conclusion The results indicated that PDT can be an excellent alternative to prevent the spread of infectious lung diseases by multidrug-resistant microorganisms in patients under mechanical ventilation and provide conditions for starting animal model experiments.
Molecules, Mar 2, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
PLOS ONE, Oct 10, 2017
The impact of substituents on the photochemical and biological properties of tetraphenylporphyrin... more The impact of substituents on the photochemical and biological properties of tetraphenylporphyrin-based photosensitizers for photodynamic therapy of cancer (PDT) as well as photodynamic inactivation of microorganisms (PDI) was examined. Spectroscopic and physicochemical properties were related with therapeutic efficacy in PDT of cancer and PDI of microbial cells in vitro. Less polar halogenated, sulfonamide porphyrins were most readily taken up by cells compared to hydrophilic and anionic porphyrins. The uptake and PDT of a hydrophilic porphyrin was significantly enhanced with incorporation in polymeric micelles (Pluronic L121). Photodynamic inactivation studies were performed against Gram-positive (S. aureus, E. faecalis), Gram-negative bacteria (E. coli, P. aeruginosa, S. marcescens) and fungal yeast (C. albicans). We observed a 6 logs reduction of S. aureus after irradiation (10 J/cm 2) in the presence of 20 μM of hydrophilic porphyrin, but this was not improved with incorporation in Pluronic L121. A 2-3 logs reduction was obtained for E. coli using similar doses, and a decrease of 3-4 logs was achieved for C. albicans. Rational substitution of tetraphenylporphyrins improves their photodynamic properties and informs on strategies to obtain photosensitizers for efficient PDT and PDI. However, the design of the photosensitizers must be accompanied by the development of tailored drug formulations.
Chemical Communications, 2023
We offer a personal account of the discovery and development of a photosensitizer for photodynami... more We offer a personal account of the discovery and development of a photosensitizer for photodynamic therapy (PDT) of cancer, from bench to bedside. We emphasize the more chemical aspects of drug discovery and drug development, namely the chemical landscape at the time of the discovery, the breakthrough in the field offered by stable bacteriochlorins, the challenges of synthesising a significant amount of the product with high purity for preclinical studies, the factors that relate molecular structure to pharmacology in PDT, the mechanistic interpretation of preclinical data and the management of unexpected results. Special attention is given to the implications of atropisomerism and immune responses in PDT.
Antibiotics, Apr 30, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Photochemical and Photobiological Sciences, Apr 1, 2020
Antimicrobial resistance is threatening to overshadow last century's medical advances. Previously... more Antimicrobial resistance is threatening to overshadow last century's medical advances. Previously eradicated infectious diseases are now resurgent as multi-drug resistant strains, leading to expensive, toxic and, in some cases, ineffective antimicrobial treatments. Given this outlook, researchers are willing to investigate novel antimicrobial treatments that may be able to deal with antimicrobial resistance, namely photodynamic therapy (PDT). PDT relies on the generation of toxic reactive oxygen species (ROS) in the presence of light and a photosensitizer (PS) molecule. PDT has been known for almost a century, but most of its applications have been directed towards the treatment of cancer and topical diseases. Unlike classical antimicrobial chemotherapy treatments, photodynamic antimicrobial chemotherapy (PACT) has a non-target specific mechanism of action, based on the generation of ROS, working against cellular membranes, walls, proteins, lipids and nucleic acids. This non-specific mechanism diminishes the chances of bacteria developing resistance. However, PSs usually are large molecules, prone to aggregation, diminishing their efficiency. This review will report the development of materials obtained from natural sources, as delivery systems for photosensitizing molecules against microorganisms. The present work emphasizes on the biological results rather than on the synthesis routes to prepare the conjugates. Also, it discusses the current state of the art, providing our perspective on the field.
Molecules
Herein we describe the design of natural curcumin ester and ether derivatives and their applicati... more Herein we describe the design of natural curcumin ester and ether derivatives and their application as potential bioplasticizers, to prepare photosensitive phthalate-free PVC-based materials. The preparation of PVC-based films incorporating several loadings of newly synthesized curcumin derivatives along with their standard solid-state characterization is also described. Remarkably, the plasticizing effect of the curcumin derivatives in the PVC material was found to be similar to that observed in previous PVC–phthalate materials. Finally, studies applying these new materials in the photoinactivation of S. aureus planktonic cultures revealed a strong structure/activity correlation, with the photosensitive materials reaching up to 6 log CFU reduction at low irradiation intensities.
Molecules, 2022
Four stereoisomeric monoether derivatives, based on axially chiral (R)- or (S)-BINOL bearing a ch... more Four stereoisomeric monoether derivatives, based on axially chiral (R)- or (S)-BINOL bearing a chiral (+)- or (−)-neomenthyloxy group were synthesised and fully characterised by NMR spectroscopy and X-ray crystallography. The respective tris-monophosphites were thereof prepared and fully characterised. The coordination ability of the new bulky phosphites with Rh(CO)2(acac), was attested by 31P NMR, which presented a doublet in the range of δ = 120 ppm, with a 1J(103Rh-31P) coupling constant of 290 Hz. The new tris-binaphthyl phosphite ligands were further characterised by DFT computational methods, which allowed us to calculate an electronic (CEP) parameter of 2083.2 cm−1 and an extremely large cone angle of 345°, decreasing to 265° upon coordination with a metal atom. Furthermore, the monophosphites were applied as ligands in rhodium-catalysed hydroformylation of styrene, leading to complete conversions in 4 h, 100% chemoselectivity for aldehydes and up to 98% iso-regioselectivity....
Catalysts, 2020
The quest for active, yet “green” non-toxic catalysts is a continuous challenge. In this work, co... more The quest for active, yet “green” non-toxic catalysts is a continuous challenge. In this work, covalently linked hybrid porphyrin–nanodiamonds were prepared via ipso nitro substitution reaction and characterized by X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, infrared spectroscopy (IR) and thermogravimetry-differential scanning calorimetry (TG-DSC). The amine-functionalized nanodiamonds (ND@NH2) and 2-nitro-5,10,15,20-tetra(4-trifluoromethylphenyl)porphyrin covalently linked to nanodiamonds (ND@βNH-TPPpCF3) were tested using Allium cepa as a plant model, and showed neither phytotoxicity nor cytotoxicity. The hybrid nanodiamond–copper(II)–porphyrin material ND@βNH-TPPpCF3-Cu(II) was also evaluated as a reusable catalyst in cyclohexene allylic oxidation, and displayed a remarkable turnover number (TON) value of ≈265,000, using O2 as green oxidant, in the total absence of sacrificial additives, which is the highest activity ever reported for said allylic oxidation...
Journal of Photochemistry and Photobiology, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Photochemical & Photobiological Sciences, 2021
Photodynamic therapy is witnessing a revival of its origins as a response to the rise of multi-dr... more Photodynamic therapy is witnessing a revival of its origins as a response to the rise of multi-drug resistant infections and the shortage of new classes of antibiotics. Photodynamic disinfection (PDDI) of microorganisms is making progresses in preclinical models and in clinical cases, and the perception of its role in the clinical armamentarium for the management of infectious diseases is changing. We review the positioning of PDDI from the perspective of its ability to respond to clinical needs. Emphasis is placed on the pipeline of photosensitizers that proved effective to inactivate biofilms, showed efficacy in animal models of infectious diseases or reached clinical trials. Novel opportunities resulting from the COVID-19 pandemic are briefly discussed. The molecular features of promising photosensitizers are emphasized and contrasted with those of photosensitizers used in the treatment of solid tumors. The development of photosensitizers has been accompanied by the fabrication o...
Catalysts, 2021
Two heterogeneous catalysts, MNP@SiO2-N-Xantphos/Rh(I) and MNP@SiO2-NH-C-scorpionate/Fe(II), were... more Two heterogeneous catalysts, MNP@SiO2-N-Xantphos/Rh(I) and MNP@SiO2-NH-C-scorpionate/Fe(II), were prepared by reaction of chloro-functionalized MNP@SiO2 with N-Xantphos and amino-functionalized MNP@SiO2 with iron(II)/C-allyl-scorpionate through nucleophilic substitution and hydroaminomethylation reactions, respectively. All catalysts were characterized using standard spectroscopic means, transmission electron microscopy (TEM), thermogravimetry (TG), and inductively coupled plasma optical emission spectrometry (ICP-OES). An active and highly selective one-pot hydroformylation/acetalization homogeneous system for the transformation of terminal and highly substituted olefins (including terpenes) onto ethyl acetals is described. A synergic effect of bimetallic Rh(I)/P and Fe(II)/C-scorpionate catalysts is disclosed for the first time. The further sequential use of the heterogeneous catalysts, MNP@SiO2-N-Xantphos/Rh(I) and MNP@SiO2-NH-C-scorpionate/Fe(II) in hydroformylation/acetalizatio...
International Journal of Molecular Sciences, 2020
A class of amphiphilic photosensitizers for photodynamic therapy (PDT) was developed. Sulfonate e... more A class of amphiphilic photosensitizers for photodynamic therapy (PDT) was developed. Sulfonate esters of modified porphyrins bearing—F substituents in the ortho positions of the phenyl rings have adequate properties for PDT, including absorption in the red, increased cellular uptake, favorable intracellular localization, low cytotoxicity, and high phototoxicity against A549 (human lung adenocarcinoma) and CT26 (murine colon carcinoma) cells. Moreover, the role of type I and type II photochemical processes was assessed by fluorescent probes specific for various reactive oxygen species (ROS). The photodynamic effect is improved not only by enhanced cellular uptake but also by the high generation of both singlet oxygen and oxygen-centered radicals. All of the presented results support the idea that the rational design of photosensitizers for PDT can be further improved by better understanding the determinants affecting its therapeutic efficiency and explain how smart structural modifi...
Molecules, 2020
The synthesis and structural modulation of five pro-ligand salts was achieved using alternative s... more The synthesis and structural modulation of five pro-ligand salts was achieved using alternative sustainable synthetic strategies, the use of microwaves being the method of choice, with an 81% yield and an E factor of 43 for 3d. After complexation with Fe3(CO)12 by direct reaction with the appropriate pro-ligands at 130 °C, a set of iron(II) N-heterocyclic carbene (NHC) complexes were isolated and fully characterized (via 1H and 13C NMR and IR spectroscopy and elemental analysis). The antibacterial activities of the iron(II)-NHC complexes were tested against standard World Health Organization priority bacterial strains: Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922. The results showed a significant effect of the Fe(II)-NHC side-chain on the antibacterial activity against both Gram-negative and Gram-positive bacteria. Among all compounds, the most lipophilic iron complex, 3b, was found to be the most active one, with a minimum inhibitory concentration of 8 µg/mL. Pi...
Journal of Organometallic Chemistry, 2020
The sustainable synthesis of highly functionalised formylcarboxamide compounds with biological re... more The sustainable synthesis of highly functionalised formylcarboxamide compounds with biological relevance is reported through a sequential aminocarbonylation/hydroformylation approach. The optimisation of palladium-catalysed aminocarbonylation of iodoaromatic substrates, using allylamine as nucleophile was first performed, with molybdenum hexacarbonyl as alternative CO source versus gaseous carbon monoxide. The combination of microwave irradiation with molybdenum hexacarbonyl allowed to selectively prepare a set of N-heterocyclic-based allylcarboxamides. Subsequent rhodiumcatalysed hydroformylation of the allylcarboxamide intermediates led to the preparation of new pyridine, pyrazoline and chalcone derivatives containing both carboxamide and formyl moieties.
Catalysts, 2018
The amide peptide bond type linkage is one of the most natural conjugations available, present in... more The amide peptide bond type linkage is one of the most natural conjugations available, present in many biological synthons and pharmaceutical drugs. Hence, aiming the direct conjugation of potentially biologically active compounds to phthalocyanines, herein we disclose a new strategy for direct modulation of phthalonitriles, inspired by an attractive synthetic strategy for the preparation of carboxamides based on palladium-catalyzed aminocarbonylation of aryl halides in the presence of carbon monoxide (CO) which, to our knowledge, has never been used to prepare amide-substituted phthalonitriles, the natural precursors for the synthesis of phthalocyanines. Some examples of phthalocyanines prepared thereof are also reported, along with their full spectroscopic characterization and photophysical properties initial assessment.
ACS Infectious Diseases, 2020
Gram-negative bacteria and bacteria in biofilms are very difficult to eradicate and are at the or... more Gram-negative bacteria and bacteria in biofilms are very difficult to eradicate and are at the origin of the most antibiotic-resistant bacteria. Therapeutic alternatives less susceptible to mechanisms of resistance are urgently needed to respond to an alarming increase of resistant nosocomial infections. Antibacterial photodynamic inactivation (PDI) generates oxidative stress that triggers multiple cell death mechanisms more difficult to counteract by bacteria. We explore PDI of multidrug-resistant bacterial strains collected from patients and show how positive charge distribution in the photosensitizer drug impacts on the efficacy of inactivation. We demonstrate the relevance of size for drug diffusion in biofilms. Designed meso-imidazolyl porphyrins of small size with positive charges surrounding the macrocycle enabled the inactivation of bacteria in biofilms by 6.9 log units at 5 nM photosensitizer concentration and 5 J cm-2 , which offers new opportunities to treat biofilm infections.
Royal Society Open Science, 2018
An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy... more An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N -nucleophiles, gives access, in one pot, to a new family of indole-based N -heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation ( P CO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reaction's selectivity, with the best yields for the cyclic products being obtained in the presence of (1 S , 2S )-(+)-cyclohexane-1,2-diamine ( a ) as the nucleophile, using either 5- or 7-iodoindole ...
Journal of Molecular Structure, 2019
Unsymmetrical porphyrins were rationally-designed and synthesized to investigate the relation bet... more Unsymmetrical porphyrins were rationally-designed and synthesized to investigate the relation between their structure, properties and adsorption geometries, and their relative performance as dyes in dyesensitized solar cells. Photophysics, electrochemical and TiO2 anchoring properties of the new unsymmetrical Nglycolic acid amino phenyl porphyrins were evaluated. Most dyes showed good energy matching between excited state energies and the TiO2 conduction band. Depending on the porphyrins, anchoring to TiO2 occurred with only one carboxyl anchor group or with two N-glycolic acid amino phenyl connected to opposite and adjacent phenyl groups. It was found that cell efficiencies normalized for surface coverage are strongly affected by the adsorption geometry and spacer linker flexibility. The effective distance between the porphyrin core and the TiO2 surface has key importance in cell efficiencies. The data is consistent with a through-space electron transfer and anchoring via N-glycolic acid substituents located in adjacent phenyl groups results in higher surface coverage normalized cell efficiencies.
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Papers by Mariette M. Pereira