Sara M. A. Pinto

Bio: Sara M. A. Pinto is an academic researcher from University of Coimbra. The author has contributed to research in topics: Porphyrin & Chemistry. The author has an hindex of 16, co-authored 39 publications receiving 705 citations. Previous affiliations of Sara M. A. Pinto include Universidad Miguel Hernández de Elche & University of Pavia.

Optical detection of amine vapors using ZnTriad porphyrin thin films

Abstract: In this work, we have used a tripodal porphyrin, 1,3-di[5-(3-hydroxyphenyl)-10,15,20-(triphenyl)porphyrin]-2-(5-(3-hydroxyphenyl)-10,15,20-(triphenyl) porphyrin)-2-methylpropane Zn(II) (ZnTriad), to detect amines through UV–vis spectroscopy. We have also compared ZnTriad to its single unit, Zn(II) 5,10,15,20-tetraphenylporphyrin (ZnTPP) to assess the influence of the branched structure on the molecular aggregation and sensing capabilities. The comparison between tripodal ZnTriad and monomeric ZnTPP has shown that this multiporphyrin system can reduce the aggregation of porphyrins in films prepared by spin coating. ZnTPP deposition on glass resulted in completely unusable films after less than 1 h from their preparation due to extreme aggregation, while ZnTriad showed excellent stability. The gas-sensing properties of ZnTriad films have been analyzed through their exposure to butylamine as testing gas, featuring intense and reversible spectral changes in the form of shift of their Soret band to longer wavelengths and increase of its maximum absorbance. The sensor also shows fast response and repeatability after consecutive exposure-recovery cycles. In order to test if the geometry of ZnTriad facilitates the selective detection of amines regarding their size and shape, we have chosen a total of five primary amines, being three of them linear or one-dimensional with increasing length (propylamine, butylamine and hexylamine), one planar or two-dimensional (aniline) and one three-dimensional ( tert -butylamine). The exposure of ZnTriad films to these analytes has resulted in selective responses toward the amine vapors. The linear amines have produced the fastest and more intense spectral changes on ZnTriad films, followed by tert -butylamine and aniline. Overall, films made with ZnTriad have shown great stability, preventing porphyrin aggregation, and ability to discriminate amines regarding their size and/or shape. Therefore, this porphyrin would be an excellent candidate for its inclusion in multisensor arrays.

Porphyrinoids for Chemical Sensor Applications.

Abstract: Porphyrins and related macrocycles have been intensively exploited as sensing materials in chemical sensors, since in these devices they mimic most of their biological functions, such as reversible binding, catalytic activation, and optical changes. Such a magnificent bouquet of properties allows applying porphyrin derivatives to different transducers, ranging from nanogravimetric to optical devices, also enabling the realization of multifunctional chemical sensors, in which multiple transduction mechanisms are applied to the same sensing layer. Potential applications are further expanded through sensor arrays, where cross-selective sensing layers can be applied for the analysis of complex chemical matrices. The possibility of finely tuning the macrocycle properties by synthetic modification of the different components of the porphyrin ring, such as peripheral substituents, molecular skeleton, coordinated metal, allows creating a vast library of porphyrinoid-based sensing layers. From among these, one can...

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation.

Abstract: The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the functi...

Photodynamic therapy (PDT) of cancer: from local to systemic treatment

Abstract: Photodynamic therapy (PDT) requires a medical device, a photosensitizing drug and adequate use of both to trigger biological mechanisms that can rapidly destroy the primary tumour and provide long-lasting protection against metastasis. We present a multidisciplinary view of the issues raised by the development of PDT. We show how spectroscopy, photophysics, photochemistry and pharmacokinetics of photosensitizers determine the mechanism of cell death and clinical protocols. Various examples of combinations with chemotherapies and immunotherapies illustrate the opportunities to potentiate the outcome of PDT. Particular emphasis is given to the mechanisms that can be exploited to establish PDT as a systemic treatment of solid tumours and metastatic disease.

Synthetic Chlorins, Possible Surrogates for Chlorophylls, Prepared by Derivatization of Porphyrins

Abstract: Chlorophylls make Earth green, are the central constituents in the engine of photosynthesis, and not surprisingly have garnered immense attention. A chlorin, the core chromophore of a chlorophyll, is a dihydroporphyrin macrocycle that contains one pyrroline ring and three pyrrole rings. The dominant method for the synthesis of chlorins has entailed the derivatization of porphyrins. The present review covers the ostensibly simple conversion of porphyrins, regardless of synthetic or biological origin, to chlorins. The period covered encompasses the entire history since the beginnings of chlorin synthetic chemistry in the early 20th century through 2015. Representative transformations include hydrogenation, cycloaddition, annulation, and diverse “breaking and mending” approaches. Altogether, the synthesis of >1000 chlorins or chlorin-like compounds (containing >50 distinct pyrroline motifs) is described. Such diversity animates the question “what structural features are essential for a chlorin to resemble ch...