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da Silva CF, Ramos LCB, Rohrabaugh TN, Vandevord JM, da Silva RS, Turro C, Nikolaou S. Exploring the structure of a ruthenium acetate cluster for biological purposes. INORG CHEM COMMUN 2020. [DOI: 10.1016/j.inoche.2020.107810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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da Silva CFN, Al-Afyouni M, Xue C, Ferreira FHDC, Costa LAS, Turro C, Nikolaou S. Syntheses and electronic, electrochemical, and theoretical studies of a series of μ-oxo-triruthenium carboxylates bearing orthometalated phenazines. Dalton Trans 2020; 49:1688-1698. [PMID: 31956864 DOI: 10.1039/c9dt04435c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This work reports a series of five-acetate triruthenium clusters [Ru3O(OAc)5(L)(py)2]PF6, where L = dppn (benzo[i]dipyrido[3,2-a:2',3'-c]phenazine, 1); dppz (dipyrido[3,2-a:2',3'-c]phenazine, 2); CH3-dppz (7-methyldipyrido [3,2-a:2',3'-c] phenazine, 3); Cl-dppz (7-chlorodipyrido [3,2-a:2',3'-c] phenazine, 4); and phen (1,10-phenanthroline, 5). The EPR spectra collected at 10 K displayed one isotropic signal without a hyperfine structure and with g values of ∼2.0, which showed that the five-acetate triruthenium clusters are paramagnetic, and that their electronic delocalization resembled the electronic delocalization of the parent hexa-acetate complexes. 1H NMR analysis showed that the orthometalated phenazines lowered the symmetry of the compounds significantly. Inductive effects from the carbanion and ring current effects outweighed the effect of paramagnetic anisotropy and dominated the spectra. This resulted in a lack of typical correlations with ligand parameters such as pKa that are observed for the parent hexa-acetate compounds. DFT calculations allowed for a discussion of those parameters in terms of the optimized geometry of compound 2. Natural bond orbital (NBO) results, in turn, aided the rationalization of the orthometalation reaction. The intra-cluster transitions (IC) at ∼690 nm consistently shifted to higher energies, and the redox pair [Ru3O]0/+1 also shifted to more positive E1/2 values. Again, the shifts were small and produced poor correlations with phenazine basicity. Overall, the substitution of one acetate bridge caused poor π-interactions between the delocalized [Ru3O] unit and the phenazine electron cloud. fsTA experiments, performed for the first time for such systems, showed that an 2IC excited state decayed very fast on the picosecond timescale.
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Affiliation(s)
- Camila F N da Silva
- LABIQSC2 (Laboratório de Atividade Biológica e Química Supramolecular de Compostos de Coordenação), Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Ribeirão Preto - SP, Brazil.
| | - Malik Al-Afyouni
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Congcong Xue
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Frederico Henrique do C Ferreira
- NEQC - Núcleo de Estudos em Química Computacional, Departamento de Química, ICE, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, Minas Gerais, Brazil
| | - Luiz Antônio S Costa
- NEQC - Núcleo de Estudos em Química Computacional, Departamento de Química, ICE, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-900, Minas Gerais, Brazil
| | - Claudia Turro
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Sofia Nikolaou
- LABIQSC2 (Laboratório de Atividade Biológica e Química Supramolecular de Compostos de Coordenação), Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Ribeirão Preto - SP, Brazil.
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