Manganeseth(II) Schiff-base-mediated reversible deactivation controlled radical polymerization of vinyl acetate

Author(s)

Hashimoto, Patricia K. ^[1] ; Oliveira, Larissa F. ^[1] ; Riga-Rocha, Beatriz A. ^[1] ; Machado, Antonio E. H. ^[2] ; Santana, Vinicius T. ^[3] ; Nascimento, Otaciro R. ^[4] ; Carvalho-Jr, Valdemiro P. ; Goi, Beatriz E. ^[5]

Affiliation

^[1] UNESP Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP - Brazil

^[2] Univ Fed Uberlandia, Inst Quim, POB 593, BR-38400089 Uberlandia, MG - Brazil

^[3] Brno Univ Technol, CEITEC Cent European Inst Technol, Purkynova 123, Brno 61200 - Czech Republic

^[4] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13563120 Sao Carlos, SP - Brazil

^[5] Carvalho-Jr, Jr., Valdemiro P., UNESP Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-19060900 Presidente Prudente, SP - Brazil

• Document type: Journal article
• Source: NEW JOURNAL OF CHEMISTRY; v. 45, n. 22, p. 10109-10117, JUN 14 2021.
• Web of Science Citations: 0

Abstract

A series of new manganese(II) complexes were prepared with three bidentate Schiff-base ligands derived by condensation of salicylaldehyde and different cycloalkylamines (cycloalkyl = cyclopentyl, cyclohenfl, and cycloheptyl): {[}Mn(CyPen-Salicyl)(2)] (1), {[}Mn(CyHex-Salicyl)(2)] (2), and {[}Mn(CyHep-Salicyl)(2)] (3). The complexes 1-3 were characterized by FTIR, UV-vis and EPR spectroscopy, elemental analysis, cyclic voltammetry, and computational methods. The manganese(u) complexes (1-3) were used as controlling agents for the polymerization of vinyl acetate (VAc) initiated by AIBN according to an organometallic-mediated radical polymerization (OMRP) mechanism. The VAc polymerization mediated by the Mn complexes suggests that the control level can be slightly tuned through substitution of the cycloalkyl group on the Schiff-base ligand. Kinetics studies and computational investigations support an RT mechanism and a tailorable Mn complex reactivity mainly altered by steric factors of the Schiff-base ligands. The calculated thermodynamic parameters agree with the mediating ability of these complexes, since the degree of polymerization control decreases with increasing steric hindrance of the Schiff-base ligands, as well as with increasing AG values for the formation of dormant species. (AU)

• FAPESP's process: 18/19395-9 - Synthesis of new organometallic complexes of Fe (III), Co (III) and Ni (III) coordinated to asymmetric Schiff bases to mediate photo-OMRP
• Grantee: Beatriz Eleutério Goi Carvalho
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/06340-1 - Bimetallic complexes of ruthenium(II) and nickel(II): coupling of mechanistically-incompatible reactions using multifunctional catalysts via tandem catalysis
• Grantee: Valdemiro Pereira de Carvalho Júnior
• Support Opportunities: Regular Research Grants