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Abstract <p>The reaction of equimolar amounts of disodium derivative of <i>ansa</i>-bis(amidine) (L<sup>1</sup>Na<sub>2</sub>) (L<sup>1</sup> = [C<sub>6</sub>H<sub>4</sub>-1,2-{NC(Bu<sup><i>t</i></sup>)N(2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)}<sub>2</sub>]<sup>2–</sup>) with [YCl<sub>2</sub>(N(SiMe<sub>3</sub>)<sub>2</sub>)] affords the tris(amidinate) complex Y{κ<sup>4</sup>-L<sup>1</sup>}{κ<sup>2</sup>-L<sup>amd</sup>} (2) (L<sup>amd</sup> = ((2,6-Me<sub>2</sub>C<sub>6</sub>H<sub>3</sub>N)<sub>2</sub>CBu<sup><i>t</i></sup>)<sup>–</sup>). For the bulkier analogue the reactions of L<sup>2</sup>Na<sub>2</sub> (L<sup>2</sup> = [C<sub>6</sub>H<sub>4</sub>-1,2-{NC(Bu<sup><i>t</i></sup>)N(2,6-Pr<sup><i>i</i></sup><sub>2</sub>C<sub>6</sub>H<sub>3</sub>)}<sub>2</sub>]<sup>2–</sup>) with [LnCl<sub>2</sub>(N(SiMe<sub>3</sub>)<sub>2</sub>)] (Ln = Y, Nd) led to the formation of ionic compounds [Na(DME)<sub>3</sub>][Nd{κ<sup>3</sup>-L<sup>2</sup>}{κ<sup>2</sup>-L<sup>2</sup>}] (<b>3</b>) and [Na(DME)<sub>3</sub>][Y{κ<sup>3</sup>-L<sup>2</sup>}<sub>2</sub>] (<b>4</b>) featuring different types of coordination of <i>ansa</i>-bis(amidinate) ligands. Complexes <b>2</b>–<b>4</b> proved to be efficient catalysts for <i>rac</i>-lactide polymerization. Complexes <b>3</b> and <b>4</b> in the presence of Pr<sup><i>i</i></sup>OH allow to perform controlled polymerization and obtaining PLAs with molecular weights close to the theoretical ones. Complexes <b>2</b>–<b>4</b> are also active in ε-caprolactone polymerization achieving full conversion of up to 500 equivalents of ε-CL in 1–10 min giving polycaprolactone samples characterized by high M<sub>n</sub> (34.9–542.0 × 10<sup>3</sup>) and somewhat broaden molecular weight distribution <i>M</i><sub>w</sub>/<i>M</i><sub>n</sub> = 1.31–2.61.</p>

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Y3+ and Nd3+ Complexes Coordinated by ansa-Bis(amidinate) Ligands. Synthesis, Structural Features, and Catalytic Performance in Ring-Opening Polymerization of rac-Lactide and ε-Caprolactone

  • 期刊论文

  • 发表日期：

    2025年12月1日

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  • A. O. Tolpygin,
  • A. V. Cherkasov,
  • G. K. Fukin,
  • Y. V. Nelyubina,
  • A. A. Trifonov

摘要

Abstract

The reaction of equimolar amounts of disodium derivative of ansa-bis(amidine) (L1Na2) (L1 = [C6H4-1,2-{NC(But)N(2,6-Me2C6H3)}2]2–) with [YCl2(N(SiMe3)2)] affords the tris(amidinate) complex Y{κ4-L1}{κ2-Lamd} (2) (Lamd = ((2,6-Me2C6H3N)2CBut)–). For the bulkier analogue the reactions of L2Na2 (L2 = [C6H4-1,2-{NC(But)N(2,6-Pri2C6H3)}2]2–) with [LnCl2(N(SiMe3)2)] (Ln = Y, Nd) led to the formation of ionic compounds [Na(DME)3][Nd{κ3-L2}{κ2-L2}] (3) and [Na(DME)3][Y{κ3-L2}2] (4) featuring different types of coordination of ansa-bis(amidinate) ligands. Complexes 2–4 proved to be efficient catalysts for rac-lactide polymerization. Complexes 3 and 4 in the presence of PriOH allow to perform controlled polymerization and obtaining PLAs with molecular weights close to the theoretical ones. Complexes 2–4 are also active in ε-caprolactone polymerization achieving full conversion of up to 500 equivalents of ε-CL in 1–10 min giving polycaprolactone samples characterized by high Mn (34.9–542.0 × 103) and somewhat broaden molecular weight distribution Mw/Mn = 1.31–2.61.