Dependent excited state absorption and dynamic of b-BF2 substituted metalloporphyrins: The metal ion effect

Author(s)

Sciuti, Lucas F. ^[1] ; Costa, Leticia D. ^[2] ; Guieu, Samuel ^{[2, 3]} ; Cocca, Leandro H. Z. ^[1] ; Iglesias, Bernardo A. ^[4] ; Mendonca, Cleber R. ^[1] ; Tome, Augusto C. ^[2] ; Faustino, M. Amparo F. ^[2] ; De Boni, Leonardo ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Aveiro, Dept Chem, LAQV REQUIMTE, P-3810193 Aveiro - Portugal

^[3] Univ Aveiro, Aveiro Inst Mat, Dept Chem, CICECO, P-3810193 Aveiro - Portugal

^[4] Univ Fed Santa Maria, Dept Quim, Lab Bioinorgan & Mat Porfirin, Av Roraima 1000, Campus Camobi, BR-97105900 Santa Maria, RS - Brazil

• Document type: Journal article
• Source: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY; v. 260, NOV 5 2021.
• Web of Science Citations: 0

Abstract

Absorption and relaxation dynamics of electronic states of free-base, Co(II), Cu(II) and Zn(II) porphyrins bearing a b-(2,2-difluoro-1,3,2-dioxaborinin-5-yl) group were investigated in dimethyl sulfoxide by using distinct time-resolved spectroscopic techniques. Furthermore, excited state absorption cross-section spectra were determined by combining white light continuum Z-Scan and transient absorption techniques. In the case of the free-base (2H) and Zn(II) porphyrins, we were able to quantify singlet \& ndash;triplet conversion by analyzing the evolution of time-resolved fluorescence. Relaxation lifetimes from the excited to the ground state were observed in both porphyrins at nanosecond time scale. However, for Co(II) and Cu(II) metalloporphyrins it was observed in the picosecond time scale through femtosecond transient absorption, indicating that both compounds relax back to the ground state only by internal conversion processes. Co(II) and Cu(II) heavy atoms seem to prohibit the radiative and intersystem crossing processes. (c) 2021 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 18/11283-7 - Nonlinear photonics: spectroscopy and advanced processing of materials
• Grantee: Cleber Renato Mendonça
• Support Opportunities: Research Projects - Thematic Grants