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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

High-field/high-frequency EPR spectroscopy on synthetic melanin: on the origin of carbon-centered radicals

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Author(s):
Paulin, J. V. [1] ; Batagin-Neto, A. [2, 1] ; Naydenov, B. [3] ; Lips, K. [4, 3, 5] ; Graeff, C. F. O. [6, 1]
Total Authors: 5
Affiliation:
[1] Sao Paulo State Univ UNESP, Sch Sci, Postgrad Program Sci & Technol Mat POSMAT, Bauru, SP - Brazil
[2] Sao Paulo State Univ UNESP, Campus Itapeva, Itapeva - Brazil
[3] Helmholtz Zentrum Berlin Mat & Energie GmbH, Berlin - Germany
[4] Univ Utah, Dept Phys & Astron, Salt Lake City, UT - USA
[5] Free Univ Berlin, Dept Phys, Berlin - Germany
[6] Sao Paulo State Univ UNESP, Sch Sci, Dept Phys, Bauru, SP - Brazil
Total Affiliations: 6
Document type: Journal article
Source: MATERIALS ADVANCES; JUL 2021.
Web of Science Citations: 0
Abstract

Among all the pigments found in nature, melanin has drawn considerable attention for bioelectronics applications as it contains a set of physicochemical properties such as antioxidant activity, metal chelation, biocompatibility, broad-band absorbance throughout the UV-visible region, hydration-dependent conductivity and intrinsic and extrinsic free radical character. A better understanding of these properties is a matter of significant importance to improve melanin-based organic devices efficiently. Therefore, the origin of melanin free-radicals was studied using continuous-wave electron paramagnetic resonance (EPR) spectroscopy at 263 GHz for standard non-functionalized and sulfonated derivatives. Our results indicated that more than one radical species should be evoked to study the free-radical nature of standard and sulfonated melanin. Additionally, we also confirm that the free-radical system of sulfonated melanin is similar to non-functionalized melanin. Based on the g-anisotropy analysis, we propose which potential units could be responsible for carbon-centered radicals. (AU)

FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
Grantee:Elson Longo da Silva
Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 12/03116-7 - Simulation of electronic and optical properties of organic materials
Grantee:Augusto Batagin Neto
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 15/23000-1 - Vertical organic field-effect transistor using dyes of natural origin as active layer
Grantee:João Vitor Paulin
Support Opportunities: Scholarships in Brazil - Doctorate