Assessment of the electronic structure of a triruthenium acetate-pyridylnaphthalimide cluster

Author(s):Show less -

Goncalves Mateus, Douglas Braz ^[1] ; da Silva Souza, Samya ^[1] ; de Bacchi Silva, Ricardo Junior ^[1] ; de Lima Batista, Ana Paula ^[1] ; Cicolani, Renato Salviato ^[1] ; Murie, Valter Eduardo ^[2] ; Nishimura, Rodolfo Hideki ^[2] ; Clososki, Giuliano Cesar ^{[1, 2]} ; Sampaio de Oliveira Filho, Antonio Gustavo ^[1] ; Demets, Gregoire Jean-Francois ^[1] ; Nikolaou, Sofia ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Av Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Fis & Quim, Av Cafe S-N, BR-14040903 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY; v. 391, MAR 15 2020.
• Web of Science Citations: 0

Abstract

A synthetic route for attaining the combination of an electroactive unit with the chromophore N-(4-pyridyl)-1,8-naphthalimide (NI-py) was developed, yielding the trinuclear ruthenium cluster {[}Ru3O(CH3COO)(6)(NI-pY)3]FF6 (1). Due to the presence of one unpaired electron in the {[}Ru3O(CH3C00)6](+) unit, 1H NMR analysis showed paramagnetic shifts in the NI-py hydrogens by displacing, for example, hydrogen ortho to the N-heteroatom in the free ligand from 8.83 ppm to 0.73 ppm in the coordinated ligand. The electronic spectrum of 1 showed absorption at 696 nm (metal -to -metal transitions of the {[}Ru3O(CH3COO)(6)] unit), and a band at 334 nm, assigned to cluster-NI-py charge transfer superimposed with the low energy pi-pi{*} NI transitions. The latter band did not show any shifts upon coordination or change in the formal charge of the {[}Ru3O(CH3COO)(6)] core, suggesting that the electronic states involved in these transitions are not perturbed significantly upon complexation. However, the comparison of both NI-py and complex luminescence spectra indicated that the metal unit can quench NI-py fluorescence. The computational calculations confirmed the electronic delocalization over the {[}Ru3O (CH3COO)(6)](+) core in the ground state and the superposition of both NI-py pi ->pi{*} and the CLCT bands. A film, assembled on a FTO electrode surface by adsorption, showed the redox pair {[}Ru3O(CH3COO)(6)](+1/0) at 0.365 V vs. SHE, which is in accordance with the NI-py strong pi-acid character. This film was electrochromic, being blue for {[}Ru3O(CH3COO)(6)(NI-py)(3)](+) and yellow for {[}Ru3O(CH3COO)(6)(NI-py)(3)](0). (AU)

• FAPESP's process: 18/18060-3 - Use of inorganic supramolecular structures for the development of functional molecules and controlled release of bioactive species
• Grantee: Sofia Nikolaou
• Support Opportunities: Regular Research Grants