Tandem ROMP/Vinyl-Addition Polymerization of Norbornene Catalyzed by a Ru/Ni Heterobimetallic Complex

Author(s)

Santos, Douglas H. N. ; Masson, Gustavo H. C. ; Silva, Eliada A. ; Rubira, Rafael J. G. ; Nascimento, Otaciro R. ; Bernardo-Gusmao, Katia ; Lima-Neto, Benedito S. ; Goi, Beatriz E. ; Carvalho-Jr, Valdemiro P.

• Document type: Journal article
• Source: JOURNAL OF POLYMER SCIENCE; v. N/A, p. 12-pg., 2025-03-29.

Abstract

The new compound (1S,4S)-N-(4-iodophenyl)bicyclo[2.2.1]hept-5-en-2-carboxamide (NBE-amide-I) was synthesized using 4-iodoaniline and 5-norbornene-2-carboxylic acid. NBE-amide-I was then used in an oxidative addition reaction with [Ni(PPh3)4] to obtain the new complex [NiI(NBE-amide)(PPh3)2] (Ni-NBE). The complexes [Ni(NBE-amide)(PPh3)(Schiff-cyclohexane)] (mono-Schiff-Ni) and [{RuCl2(eta 6-p-cymene)}mu{(Schiff-pip)Ni(aryl-NBE)(PPh3)}] (Ru-Ni-NBE) were synthesized via a one-pot reaction using Ni-NBE, salicylaldehyde, and 4-(aminomethyl)piperidine or [RuCl2(eta 6-p-cymene)(piperidine-(4-aminomethyl))] (mono-RuPip), respectively, in dichloromethane for 16 h. The mono-Ni-Schiff and Ru-Ni-NBE complexes were fully characterized using FTIR, UV-Vis, 1H and 31P{1H} NMR, MALDI-TOF, EPR, and cyclic voltammetry. These complexes were then evaluated as precatalysts for the vinyl-addition polymerization of norbornene (NBE), achieving yields of 91% and 71%, respectively, using methylaluminoxane (MAO) as the cocatalyst (Al/[Ni] = 2000). Ru-Ni-NBE was also shown to be active in the ring-opening metathesis polymerization (ROMP) of NBE, achieving yields of up to 50% in the presence of 10 equivalents of (trimethylsilyl)diazomethane (TMSDM) as the carbene source. The one-pot synthesis of a copolymer based on assisted-tandem catalysis, combining ROMP and vinyl-addition polymerization of NBE using Ru-Ni-NBE, was conducted through the sequential addition of TMSDM and MAO under previously optimized conditions. The copolymer was characterized by 1H NMR, GPC, Raman scattering, and SEM. (AU)

• FAPESP's process: 22/12417-2 - Synthesis of new heterobimetallic complexes of RuII/NiII and RuII/PdII as multifunctional catalysts in the coupling of mechanistically distinct polymerization reactions
• Grantee: Douglas Henrique Nunes Santos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 21/13128-1 - Development of new polymeric materials via coupling of mechanistically incompatible reactions using Ru/Pd and Ru/Ni heterobimetallic catalysts
• Grantee: Valdemiro Pereira de Carvalho Júnior
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/11873-1 - Organometallic complexes of Mn(II), Fe(II) and Ni(II) as CRP2 redox photocatalysts: new strategy for light curing with LEDs
• Grantee: Beatriz Eleutério Goi Carvalho
• Support Opportunities: Regular Research Grants