Titanacalixarenes in Homogeneous Catalysis: Synthesis, Conformation and Catalytic Activity in Ethylene Polymerisation

Abstract

Variously substituted titanacalixarenes were synthesised and tested for their performance as catalysts in ethylene polymerisation: p-tert-butylcalix [4]arene was derivatised to af-

Use of titanocalix[4]arenes in the ring opening polymerization of cyclic esters

“…In the same study, a couple of 1,2-dialkoxycalixij4]arene derivatives were also prepared, namely the methyloxy and a complex containing a chelating siloxide SiMe 2 , together with a number of depleted calix [4]arene complexes bearing 1,2-or 1,3-titanium dichloride motifs. 5 Whilst the behavior of the 1,2-and 1,3-systems was different, it was determined that within each series, increasing the number of alkyloxy groups present was detrimental to the catalytic activity. On variation of the R group from methyl to isobutyl in the 1,3-systems, there was no clear structural activity trend.…”

Use of Titanium Complexes Bearing Diphenolate or Calix[n]arene Ligands in α-Olefin Polymerization and the ROP of Cyclic Esters

“…The complexes proved to be efficient catalysts also for the ROP of δ-valerolactone (Table 21, entries [12][13][14][15][16]. Similarly to the previous case, 66 and 67 were shown to be better performing than their dichloride counterparts.…”

“…Molecular structure of 23 [13]. Subsequently, Taoufik, Bonnamour et al extended these studies and investigated the effect of varying the 1,3-dialkyloxy R groups (for R = methyl, ethyl, n-propyl and i-butyl) on the catalytic activity of complexes 24-27 ( Figure 9) during ethylene polymerization [15]. In the same study, a couple of 1,2-dialkoxycalix [4]arene derivatives were also studied such as the previously encountered 19 containing a chelating siloxide SiMe 2 and the methyloxy 28.…”

“…Whilst the behavior of the 1,2-and 1,3-systems was different, it was determined that within each series increasing the number of alkyloxy groups present was detrimental to the catalytic activity. Moderate activity was exhibited by complex 19 containing the chelating 1,2-siloxide moiety ( Subsequently, Taoufik, Bonnamour et al extended these studies and investigated the effect of varying the 1,3-dialkyloxy R groups (for R = methyl, ethyl, n-propyl and i-butyl) on the catalytic activity of complexes 24-27 ( Figure 9) during ethylene polymerization [15]. In the same study, a couple of 1,2-dialkoxycalix [4]arene derivatives were also studied such as the previously encountered 19 containing a chelating siloxide SiMe2 and the methyloxy 28.…”

Ring a bell: Disubstituted calix[4]arene as ligand for transition metal chlorides

“…This opening of the calixarene is common with dimethylcalix [4]arene and is more pronounced when a metal ion is coordinated endo in the calixarene cavity (Fig. S4) [16,23,51,52,65,66,[68][69][70][71][72].…”