Reactivity of the p-Cymene-Ruthenium Complex with Two Phenylamines for Metathesis Polymerization of Norbornene Compared to the Reactivity of Complexes with a Single Benzylamine or Dibenzylamine

Author(s)

Silva, Eliada A. ; Santiago, Pedro H. O. ; Ellena, Javier A. ; Oliveira-Filho, Antonio G. S. ; de Lima Batista, Ana Paula ; Lima-Neto, Benedito S.

• Document type: Journal article
• Source: European Journal of Inorganic Chemistry; v. 27, n. 33, p. 12-pg., 2024-11-21.

Abstract

The complexes [RuCl(Cy)(NH2Ph)2]Cl (1), [RuCl2(Cy)(NH2Bz)] (2), and [RuCl2(Cy)(NHBz2)] (3) were synthesized under identical conditions from [RuCl2(Cy)]2, where Cy=eta 6-p-cymene, Ph=phenyl, and Bz=benzyl. X-ray crystallography revealed an additional NH2Ph ligand in 1, distinguishing it from the neutral mono-amine complexes 2 and 3. The number of amines in these complexes did not correlate clearly with the sigma-donor character or steric hindrance of the amines. Different reactivities were observed for the ROMP of norbornene (NBE), as measured by batch reactions and kinetic studies using Raman and 1H NMR spectroscopy. Semiquantitative conversions reached up to 90 % with complex 1 and around 40 % with complexes 2 and 3. DFT calculations supported the hypothesis that the reaction for complex 1 involves the release of an amine through a dissociative mechanism, whereas complexes 2 and 3 react through an associative mechanism involving amine loss. The presence of an amine in the propagation species of complex 1 suggests the participation of the amine as an ancillary ligand. All carbene species are of the eta 2-p-cymene type, and the catalytic cycle follows a 14-16-14 electron counting mechanism. (AU)

• FAPESP's process: 17/15850-0 - X-ray diffraction as a tool in potential drug development
• Grantee: Eduardo Ernesto Castellano
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 21/00675-4 - Tying up materials for electrochemical energy storage and catalysis
• Grantee: Roberto Manuel Torresi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/12043-5 - Structure and spectroscopy of first row transition metal complexes: a computacional approach
• Grantee: Ana Paula de Lima Batista
• Support Opportunities: Regular Research Grants
• FAPESP's process: 23/17102-2 - Sustainable chemistry based on olefin metathesis: development of olefins from bio-molecules via economically viable catalysts.
• Grantee: Benedito dos Santos Lima Neto
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/10066-5 - Crystallographic and structural study of new substances with potential biological activities
• Grantee: Pedro Henrique de Oliveira Santiago
• Support Opportunities: Scholarships in Brazil - Post-Doctoral