Synthesis, characterization, and reactivity of titanium(IV) complexes supported by proximally bridged p-tert-butylcalix[4]arene ligands

Oleg V. Ozerov, Nigam P. Rath, Folami T. Ladipo

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28 Scopus citations

Abstract

Treatment of dilithium or dipotassium salt of p-tert-butylcalix[4]arene with tBuPCl2 or PhPCl2 produced 1,2-alternate phosphorus-bridged p-tert-butylcalix[4]arene derivatives (tBuPC)H2 (1) and (PhPC)H2 (2), respectively. An X-ray diffraction study of 2 showed that it exists in 1,2-alternate conformation. Reaction of 2 with sulfur gave (PhSPC)H2 (3), which exists in cone conformation. Treatment of TiCl4 with 1-3 produced the corresponding dichlorides L2TiCl2 [L2=tBuPC (5); PhPC (6); and PhSPC (7)]. Reaction of R2Mg·2THF (R=Me or CH2Ph) with (DMSC)TiCl2 (8) yielded (DMSC)TiMe2 (9) and (DMSC)Ti(CH2Ph)2 (10), respectively. Cationic derivatives [(DMSC)Ti(NCCH3)Me2]BArF4 (11) and [(DMSC)Ti(NCCH3)(CH2Ph)]BArF4 (12) were prepared from the respective reactions of 9 and 10 with [Ph3C]BArF4 [ArF=(CF3)2C6H3] in the presence of CH3CN. Similarly, 9 and 10 reacted with [Ph3C]OTf (one equivalent) to yield [(DMSC)Ti(OTf)Me2] (13) and [(DMSC)Ti(OTf)(CH2Ph)] (14), respectively. NMR data showed that the more exposed exo-alkyl was abstracted. Complexes 5-10 and 14 showed modest ethylene polymerization activities at 25°C with 500 molar equivalents of methylalumoxane (MAO) as cocatalyst.

Original languageEnglish
Pages (from-to)223-233
Number of pages11
JournalJournal of Organometallic Chemistry
Volume586
Issue number2
DOIs
StatePublished - Sep 5 1999

Bibliographical note

Funding Information:
Thanks are expressed to the Kentucky National Science Foundation EPSCoR Program (grant number EPS-9452895) for support of this work and to the Chemistry Department of the University of Kentucky for the award of fellowships to O.V.O. The authors also thank Professors Jack Selegue and Mark Meier for helpful discussions.

Keywords

  • Aryloxide ligand
  • Calix[4]arene ligand
  • Olefin polymerization
  • Titanium(IV)

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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