The dichloro titanium complexes (OSSOtBu)TiCl2 (1) and (OSSOCum)TiCl2 (2) bearing o-phenylene-bridged OSSO-type ligands [OSSOtBu-H = 6,6′-((1,2-phenylenebis(sulfanediyl))bis(methylene))bis(2,4-di-tert-butyphenol) and OSSOCum-H = 6,6′-((1,2-phenylenebis(sulfanediyl))bis(methylene))bis(2,4-bis(2-phenylpropan-2-yl)phenol)] were prepared and characterized. The X-ray structure of 1 revealed that Ti atom has an octahedral coordination geometry with an fac-fac wrapping of the [OSSO] ligand. In solution at 25 °C, 1 mainly retains the C2 symmetric structure, whereas 2 shows an equilibrium between C2- and C1-symmetric stereoisomers. Activation of 2 with (Ph3C)[B(C6F5)4] led to a highly active catalytic system with an activity of 238 kgPE·molcat-1·bar-1·h-1 linear polyethylene with a Tm of 122 °C and Mw of 107 kDa were obtained under these conditions. Catalyst 1 displayed the moderate activity of 59 kgPE·molcat-1·bar-1·h-1. Gel permeation chromatography analysis revealed the formation of high-molecular-weight polyethylenes with very large distributions of the molecular weights, indicating a low control of the polymerization process, probably becaue of the presence of different active species in solution. Density functional theory investigation provides a rational for the relative high-molecular-weight polymers obtained with these complexes. The precatalyst 2 was also active in propylene polymerization producing atactic oligomers terminated with unsaturated end groups.

Phenylene-Bridged OSSO-Type Titanium Complexes in the Polymerization of Ethylene and Propylene

Della Monica, Francesco;
2018-01-01

Abstract

The dichloro titanium complexes (OSSOtBu)TiCl2 (1) and (OSSOCum)TiCl2 (2) bearing o-phenylene-bridged OSSO-type ligands [OSSOtBu-H = 6,6′-((1,2-phenylenebis(sulfanediyl))bis(methylene))bis(2,4-di-tert-butyphenol) and OSSOCum-H = 6,6′-((1,2-phenylenebis(sulfanediyl))bis(methylene))bis(2,4-bis(2-phenylpropan-2-yl)phenol)] were prepared and characterized. The X-ray structure of 1 revealed that Ti atom has an octahedral coordination geometry with an fac-fac wrapping of the [OSSO] ligand. In solution at 25 °C, 1 mainly retains the C2 symmetric structure, whereas 2 shows an equilibrium between C2- and C1-symmetric stereoisomers. Activation of 2 with (Ph3C)[B(C6F5)4] led to a highly active catalytic system with an activity of 238 kgPE·molcat-1·bar-1·h-1 linear polyethylene with a Tm of 122 °C and Mw of 107 kDa were obtained under these conditions. Catalyst 1 displayed the moderate activity of 59 kgPE·molcat-1·bar-1·h-1. Gel permeation chromatography analysis revealed the formation of high-molecular-weight polyethylenes with very large distributions of the molecular weights, indicating a low control of the polymerization process, probably becaue of the presence of different active species in solution. Density functional theory investigation provides a rational for the relative high-molecular-weight polymers obtained with these complexes. The precatalyst 2 was also active in propylene polymerization producing atactic oligomers terminated with unsaturated end groups.
2018
2018
https://pubs.acs.org/doi/10.1021/acsomega.8b01550
Chemistry (all); Chemical Engineering (all)
Lapenta, Rosita; Buonerba, Antonio; Luciano, Ermanno; Della Monica, Francesco; DE NISI, Assunta; Monari, Magda; Grassi, Alfonso; Capacchione, Carmine;...espandi
File in questo prodotto:
File Dimensione Formato  
030 - Phenylene-Bridged OSSO-Type Titanium Complexes in the Polymerization of Ethylene and Propylene.pdf

accesso aperto

Tipologia: Versione Editoriale (PDF)
Licenza: Creative commons
Dimensione 1.22 MB
Formato Adobe PDF
1.22 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2129302
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 5
social impact