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

Abstract

Titanocalix[4]arenes are shown to be active for the ROP of cyclic esters under N2 or air with the mono-methoxy complex [Ti(NCMe)Cl(p-tert-butylcalix[4]arene(O)3(OMe))] performing best.

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

“…We have recently synthesized the chlorotitanium diphenolate complex 63, by treatment of the proligand 46 with an equimolar amount of [TiCl 4 ] (Scheme 6) [29]. Scheme 6.…”

“…Catalysts 2020, 10, 210 19 of 29 Scheme 6. Synthesis of the chlorotitanium diphenolate complex 63 [29].…”

“…(R = n-decyl) (67) was also synthesized and characterized by X-Ray diffraction studies on single crystals (Figures 17 and 18). Recently, we have reported the isolation of acetonitrile solvates of the known titanocalix [4]arene complexes 24, 26 (bearing 1,3-methoxy-and propoxy-substituents, respectively) as well as new solvate forms of their analogues 65 and 66 (1,3-pentoxy-and monomethoxy derivative, respectively, Figure 16) [29]. A chloro-bridged compound {[TiL(O)3(OR)]2(-Cl)2} .…”

“…Polymerization of cyclic esters catalyzed by Si-supported-66[29]. Determined by 1 H-NMR spectroscopy on crude reaction mixture.…”

“…Comparison between the activities of various Ti-based ROP catalysts[29]. Determined by 1 H-NMR spectroscopy on crude reaction mixture based on the monomer.…”