onometallic and heterobimetallic ruthenium (II) and palladium (II) complexes based on a pyridine-hydrazone ligand as bifunctional catalysts for ROMP of norbornene and ethylene polymerizatio

Author(s)

de Santana Gois, Patrik Dione ^[1] ; Pereira Maia, Juliana Iris ^[2] ; Cicero Masson, Gustavo Henrique ^[1] ; Martins, Daniele Maria ^[3] ; da Hora Machado, Antonio Eduardo ^[4] ; Goi, Beatriz Eleuterio ^[1] ; da Silva Maia, Pedro Ivo ^[2] ; de Carvalho-Jr, Valdemiro Pereira

Affiliation

^[1] UNESP Univ Estadual Paulista, Fac Ciencias & Tecnol, BR-38400089 Presidente Prudente, SP - Brazil

^[2] Univ Fed Triangulo Mineiro, Dept Qulm, BR-38025440 Uberaba, MG - Brazil

^[3] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos - Brazil

^[4] Univ Fed Uberlandia, Inst Quim, Uberlandia, MG - Brazil

• Document type: Journal article
• Source: Applied Organometallic Chemistry; v. 36, n. 2 OCT 2021.
• Web of Science Citations: 0

Abstract

The monometallic complex {[}Pd(L)(PPh3)] (mono-Pd) was synthesized using a potentially tridentate hydrazone (H2L) and used as precursor to prepare a heterobimetallic ruthenium (II)-palladium (II) complex {[}Cl-2(p-cymene)Ru(mu-L)Pd (PPh3)] (Ru-Pd). Mono-Pd and Ru-Pd were characterized by fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), H-1, C-13[H-1] and P-31[H-1] nuclear magnetic ressonance(NMR) spectroscopy, elemental analysis, cyclic voltammetry, matrix-assisted laser desorption/ionization - time of flight (MALDI-TOF) mass spectrometry, and computational methods. The mono-Pd was additionally studied by single-crystal X-ray diffraction. The complex {[}RuCl2(p-cymene)(Isoniazid)] (mono-Ru) was also obtained following literature methods aiming a comparison in the catalytic activity. The ring opening metathesis polymerization (ROMP) of norbornene (NBE) using mono-Ru or Ru-Pd as precatalysts in the presence of ethyl diazoacetate (EDA) was evaluated as a function of time (10-60 min) using {[}NBE]/{[}EDA]/{[}Ru] = 5000/28/1 at 50 degrees C. The time increases produced good yields of polyNBE, reaching 38% and 46% for mono-Ru and Ru-Pd, respectively. The polyNBE produced was measured by size-exclusion chromatography (SEC) and reached an order of magnitude of 10(5) g center dot mol(-1) of M-n, with <SIC> values ranging from 2.51 to 1.86 for mono-Ru and from 3.50 to 1.66 for Ru-Pd. The catalytic activity of mono-Pd and Ru-Pd on ethylene polymerization was assessed with a range of {[}Al]/{[}Pd] molar ratio between 350 and 1750, 30-70 degrees C temperature, 2 to 4 h reaction time, and total reaction volume of 25 and 50 ml. Mono-Pd achieved an activity of 22.80 kg PE (mol Pd)(-1) h(-1) at 60 degrees C after 4 h using {[}Al]/{[}Pd] = 1050, 7 mu mol of catalyst in 25 ml of toluene, and 116 psi ethylene. For Ru-Pd, an activity of 20.35 kg PE (mol Pd)(-1) h(-1) at 60 degrees C after 4 h was obtained using {[}Al]/{[}Pd] = 1750, 7 mu mol of catalyst in 25 ml of toluene, and 116 psi ethylene. Overall, Ru-Pd showed to be active in both ROMP and ethylene polymerization reactions, being categorized as a bifunctional catalyst. (AU)

• 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
• 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