The pi-donor/acceptor trans effect on NO release in ruthenium nitrosyl complexes: a computational insight

Author(s)

Orenha, Renato Pereira ^[1] ; Morgon, Nelson Henrique ^[2] ; Silva, Graziele Cappato Guerra ^[1] ; Caramori, Giovanni Finoto ^[3] ; Parreira, Renato Luis Tame ^[1]

Affiliation

^[1] Univ Franca, Nucleo Pesquisas Ciencias Exatas & Tecnol, Franca, SP - Brazil

^[2] Univ Estadual Campinas, Inst Quim, CP 6154, BR-13083970 Campinas, SP - Brazil

^[3] Univ Fed Santa Catarina, Dept Quim, Campus Univ Trindade, CP 476, BR-88040900 Florianopolis, SC - Brazil

• Document type: Journal article
• Source: NEW JOURNAL OF CHEMISTRY; v. 45, n. 20 APR 2021.
• Web of Science Citations: 0

Abstract

Nitric oxide (NO) molecules are associated with diverse biochemical routes. Ruthenium complexes are widely used as model structures to control NO availability. In this study, the NO release mechanism in trans-{[}RuCl(NO)(NH3)(4)](2+) and trans-{[}Ru(NO)(NH3)(4)(P(OEt)(3))](3+) complexes, containing trans ligands with a pi-donor (Cl-) or pi-acceptor (P(OEt)(3)) character, respectively, is elucidated. Typically, a chemical reduction reaction is necessary to facilitate the NO release from these metal complexes. The protonation of trans-{[}RuCl(NO)(NH3)(4)](+), and not the aquation of the chloride ligand, appears as decisive to promote the NO release. The HNO ligand substituted with one external water molecule can promote the Cl- release, explaining the presence of the anion Cl- in the reaction environment, as evidenced by experimental results. The HNO compound can reduce the remaining metal complex and protonate an external H2O molecule to produce the NO molecule in an aqueous medium. The reduced pi-acceptor-Ru-NO complex can readily release the NO ligand. Complexes containing trans pi-acceptor ligands have lower activation energy barriers for NO release than those containing trans pi-donor ligands, which is totally in line with the experimental data available. The protonation of the NO ligand in pi-acceptor-Ru-NO complexes does not decrease the energy barrier related to the NO release reaction. These data show relevant aspects for the development of structures capable of donating the NO molecule. (AU)

• FAPESP's process: 11/07623-8 - The use of quantum-mechanical methods to study the bonds and chemical interactions in self-organizing systems with applications in catalysis, medicinal chemistry, electrochromism, energy storage and conversion
• Grantee: Renato Luis Tame Parreira
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 17/24856-2 - The Mechanism of the Substitution Reaction of the Ligand Nitrosyl by Aqua in Ruthenium Coordination Compounds
• Grantee: Renato Pereira Orenha
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/00543-0 - How modulate the Ruthenium-NO chemical bond from ligands of different nature?
• Grantee: Graziele Cappato Guerra Silva
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 15/22338-9 - Study of the interaction between drugs and human serum albumin (HSA) based on computer simulation, DFT and TDDFT, experiments of electronic circular dichroism, ECD, and determination of the bond formation constant
• Grantee: Aguinaldo Robinson de Souza
• Support Opportunities: Regular Research Grants