Synthesis of Homo- and Heteronuclear Rare-Earth Metal Complexes Stabilized by Ethanolamine-Bridged Bis(phenolato) Ligands and Their Application in Catalyzing Reactions of CO₂ and Epoxides

Abstract

A series of homonuclear rare-earth (RE) metal complexes (1 Y , 2 Yb , 3 Nd , and 4 La ) and heteronuclear RE–Zn complexes (1 Y–Zn , 3 Nd–Zn , and 5 Sm–Zn ) stabilized by ethanolamine-bridged bis­(phenolato) ligands was prepared and structurally characterized. Heteronuclear complexes are assembled through bridging acetate ligands, and their formation and characterization add to the diversity of 3d–4f complexes. Their activities in mediating reactions of CO2 and epoxides were evaluated and compared. Heteronuclear RE–Zn complexes found application in the copolymerization of cyclohexene oxide and CO2, giving rise to acetate-group-capped copolymers. Homonuclear complexes showed good activity in catalyzing the cycloaddition of variously monosubstituted epoxides and CO2 (1 bar), generating cyclic carbonates in 65–96% yield. For sterically hindered disubstituted epoxides, good yields of 60–91% were achieved in the presence of 10 bar CO2.

Advances in heterometallic ring-opening (co)polymerisation catalysis

“…Epoxide activation is a key ROCOP step, and Ln metals have displayed good monomer coordination in ROP 53 , 55 , 58 , 59 . A range of Ln/Zn complexes have also been developed for CHO/CO 2 ROCOP, including complexes 29a-b (Ln = Nd, Y) 96 , 30b-c (Ln = Y, Nd or Sm) 97 and 31a-j (Ln = Y, Lu, Dy, Sm or La) 98 (Fig. 7 ).…”

Dichiral [4.4.3.01,5]tridecane copper(II) cluster derived from a tripodal ligand having unsymmetrical podands and the linker: Synthesis, structure, surface grafting and catalytic aspects

“…The solvent was removed under reduced pressure to afford a pale yellow solid. (C 14 ), 127.7 (C 21 ), 128.2 (C 12,16,20 ), 129.0 (C 13,15 ), 130.6 (C 22 ), 132.8 (C 5 ), 137.3 (C 11 ), 140.0 (C 23 ), 155.4 (C 1 ), 158.1 (C 19 (2) The tripodal ligand 2 (1.03 mmol, 0.50 g) and sodium methoxide (3.09 mmol, 0.17 g) were dissolved in methanol (50 ml). The solution was stirred for 10 min at room temperature.…”

“…The most recent contribution of bisphenolate armed [4.4.3.0 1,5 ]tridecane metallatranes as reaction mediators includes copolymerization reactions of CO 2 and cyclohexene oxide, polymerization of methacrylate, hydrophosphination of alkenes, alkynes and heterocumulenes, ring-opening polymerization of L-lactic acid, o-carboxy anhydrides and L-lactide, epoxidation, sulfoxidation and catechol oxidation and cycloaddition of epoxides. [12][13][14][15][16][17][18][19][20][21][22][23][24] The metal centres of metallatrane catalysts are widely distributed among various elements, that is, s-block (K), p-block (Al), d-block (Ti, Zr, Zn, Cr, V, Mo, W) and f-block elements (Y, Yb, Nd, La, Sm). Although bisphenolate atranes of Fe(III), Co(III), Cu(II), Si(IV) and Sn(IV) are known; however, their use in catalysis is rarely reported.…”

Efficient Synthesis of Cyclic Carbonates from Unsaturated Acids and Carbon Dioxide and their Application in the Synthesis of Biobased Polyurethanes

“…The combination of 1 mol % of a yttrium complex and 3 mol % of tetrabutylammonium bromide (TBAB) enabled the synthesis of cyclic carbonates from terminal epoxides under ambient reaction conditions (25 °C and 1 bar) [16f] . On the other hand, the combination of 0.2 mol % of a bimetallic lanthanum complex and 0.4 mol % of TBAB catalyzed the formation of cyclic carbonates in high yields at 100 °C and one bar of CO 2 for 18 h from their corresponding epoxides [16g] …”