Search

Your search keyword '"Maçôas, Ermelinda M. S."' showing total 31 results
Start Over Author "Maçôas, Ermelinda M. S."
31 results on '"Maçôas, Ermelinda M. S."'

1. Safety assessment of new nanodiamonds@corrole hybrids addressed by the response of RAW-264.7 macrophages

Author

Santos, Carla I. M., primary, Cicuéndez, Mónica, additional, Gonçalves, Gil, additional, Rodríguez-Pérez, Laura, additional, Portolés, M. Teresa, additional, Faustino, M. Amparo F., additional, Herranz, M. Ángeles, additional, Neves, M. Graça P. M. S., additional, Martinho, José M. G., additional, Maçôas, Ermelinda M. S., additional, and Martín, Nazario, additional

Published
2023
Full Text
View/download PDF

2. Enhanced Photodynamic Therapy Effects of Graphene Quantum Dots Conjugated with Aminoporphyrins

Author

Santos, Carla I. M., primary, Rodríguez-Pérez, Laura, additional, Gonçalves, Gil, additional, Dias, Cristina J., additional, Monteiro, Fátima, additional, Faustino, Maria do Amparo F., additional, Vieira, Sandra I., additional, Helguero, Luisa A., additional, Herranz, María Ángeles, additional, Martín, Nazario, additional, Neves, M. Graça P. M. S., additional, Martinho, José M. G., additional, and Maçôas, Ermelinda M. S., additional

Published
2021
Full Text
View/download PDF

18. Role of Vibrational Dynamics in Electronic Relaxationof Cr(acac)3.

Author

Maçôas, Ermelinda M. S., Mustalahti, Satu, Myllyperkiö, Pasi, Kunttu, Henrik, and Pettersson, Mika

Subjects
*RELAXATION phenomena, *VINYL chloride, *VIBRATIONAL redistribution (Molecular physics), *CHROMIUM compounds, *TIME-resolved spectroscopy, *INFRARED spectroscopy
Abstract

Ultrafastenergy relaxation of Cr(acac)3dissolved intetrachloroethylene (TCE) is studied by time-resolved infrared (TRIR)spectroscopy by using electronic and vibrational excitation. Afterelectronic excitation at 400 or 345 nm, the ground state recoversin two time scales: 15 ps (major pathway) and 800 ps (minor pathway),corresponding to fast electronic transition to the ground state andintermediate trapping on the long-lived 2E state followedby intersystem crossing (ISC) to the ground state. The quantum yieldfor the fast recovery of the ground state depends on the excitationwavelength, being higher for 345 nm. Vibrational cooling (VC) occurson the electronic excited states with a time constant of ∼7ps and on the ground electronic state with a time constant of ∼12ps. A kinetic model that explains the observed dynamics is presented.The key point of the model is that the ground-state recovery occursvia thermally activated back-intersystem-crossing (b-ISC) to the quartetmanifold presumably via multiple curve crossings that are sampledwhile the system is vibrationally hot. This underlines the importanceof vibrational cooling as a determining factor for the electronicrelaxation chain. Vibrational excitation of the νCCand νCO vibrations also revealed a subpicosecond (300–700fs) intramolecular vibrational redistribution (IVR) process from thelocalized vibrational states to the bath of vibrational excitations. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

28. Relaxation Dynamics of Cr(acac)3 Probed by Ultrafast Infrared Spectroscopy.

Author

Maçôas, Ermelinda M. S., Kananavicius, Robertas, Myllyperkia, Pasi, Pettersson, Mika, and Kunttu, Henrik

Subjects
*CHROMIUM compounds, *MOLECULAR dynamics, *INFRARED spectroscopy, *INORGANIC compounds, *PHYSICS
Abstract

The article describes the dynamics of Cr(acac)3 (acac = deprotonated monoanion of acetylacetone) by ultrafast infrared (IR) spectroscopy. According to the authors, the study shows the great value of transient IR spectroscopy in inorganic photophysics. They add the results suggest that most of the ground state population of Cr(acac)3 recovers with a time constant of 15 ps and the rest follows the lifetime of the ²E state.

Published
2007
Full Text
View/download PDF

30. Combining metal nanoclusters and carbon nanomaterials: Opportunities and challenges in advanced nanohybrids.

Author

Lopes RCFG, Rocha BGM, Maçôas EMS, Marques EF, and Martinho JMG

Subjects
Catalysis, Metals chemistry, Nanotechnology, Carbon chemistry, Nanostructures chemistry
Abstract

The development of functional materials with uniquely advanced properties lies at the core of nanoscience and nanotechnology. From the myriad possible combinations of organic and/or inorganic blocks, hybrids combining metal nanoclusters and carbon nanomaterials have emerged as highly attractive colloidal materials for imaging, sensing (optical and electrochemical) and catalysis, among other applications. While the metal nanoclusters provide extraordinary luminescent and electronic properties, the carbon nanomaterials (of zero, one or two dimensions) convey versatility, as well as unique interfacial, electronic, thermal, optical, and mechanical properties, which altogether can be put to use for the desired application. Herein, we present an overview of the field, for experts and non-experts, encompassing the basic properties of the building blocks, a systematic view of the chemical preparation routes and physicochemical properties of the hybrids, and a critical analysis of their ongoing and emerging applications. Challenges and opportunities, including directions towards green chemistry approaches, are also discussed., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Published
2022
Full Text
View/download PDF

31. "Click and go": simple and fast folic acid conjugation.

Author

Trindade AF, Frade RF, Maçôas EM, Graça C, Rodrigues CA, Martinho JM, and Afonso CA

Subjects
Chromatography, High Pressure Liquid, Chromatography, Reverse-Phase, Ethanolamine chemistry, HEK293 Cells, Humans, Microscopy, Confocal, Spectrometry, Fluorescence, Click Chemistry methods, Folic Acid chemistry
Abstract

Folic acid targeting by functionalization of the terminal γ-carboxylic acid is one of the most important strategies to selectively deliver chemotherapeutics and dyes to cancer cells which overexpress folate receptors. However, conjugation of folic acid is limited by its unique solubility and by selectivity issues imposing the need for expensive preparative reverse-phase chromatographic purification to isolate γ-folate conjugates. Herein is provided a novel synthetic tool for the synthesis of new folic acid conjugates with excellent γ-purity based on strain-promoted alkyne-azide cycloadditions with a γ-folate-cyclooctyne conjugate 3. To demonstrate the potential of this methodology several new folate conjugates were synthesized with high γ-purity and without using any type of chromatographic purification by reacting conjugate 3 with several fluorescent probes, polymers and siliceous materials bearing azide. In addition, the cycloaddition reaction between conjugate 3 and an azido-derived fluorescent dye was successfully performed in cellular media leading to an increase of fluorescence in the cells which overexpress folate receptors (NCI-H460).

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results