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<p>The reaction of equimolar amounts of ScCl<sub>3</sub> and [Ph<sub>3</sub>EOLi] (E = C, Si) afforded the monomeric dichloride complexes Ph<sub>3</sub>EOScCl<sub>2</sub>(THF)<sub>3</sub> (E = C (<b>1</b>), Si (<b>2</b>)) in 78 and 81% yields, respectively. The reaction of NdCl<sub>3</sub> with [Ph<sub>3</sub>COLi] gave the dimeric dichloride ate complex [Ph<sub>3</sub>CONd(THF){(μ-Cl)<sub>2</sub>Li(THF)<sub>2</sub>}μ-Cl]<sub>2</sub> (<b>3</b>). Under similar conditions, the reaction of NdCl<sub>3</sub> with [Ph<sub>3</sub>SiOLi] afforded the dimeric neodymium monochloride complex [(Ph<sub>3</sub>SiO)<sub>2</sub>Nd(THF)<sub>2</sub>(μ-Cl)]<sub>2</sub> (<b>4</b>) regardless of the ratio of the reagents. Complexes <b>1–4</b> involved in the two- and three-component catalytic systems (<b>1–4</b>)—[Ph<sub>3</sub>C][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>] (1: 1) and (<b>1–4</b>)—AlBu<sup>i</sup><sub>3</sub>—[Ph<sub>3</sub>C][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>] (1: 10: 1) initiate the polymerization of isoprene (IP) at room temperature and provide the 14–100% monomer-to-polymer conversion ([IP]/[Ln] = 1000) within 1 to 24 h. The synthesized polymer samples have predominantly a <i>trans</i>-1,4 structure (59.1–80.6%), a low number-average molecular weight (<i>M</i><sub>n</sub> = 0.71–12.71 · 10<sup>3</sup>), and a relatively broad molecular weight distribution (<i>M</i><sub>w</sub>/<i>M</i><sub>n</sub> = = 1.90–4.01). The reaction of complex <b>1</b> with [Ph<sub>3</sub>C][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>] (1: 1) gave the cationic dichloride complex [ScCl<sub>2</sub>(THF)<sub>4</sub>]<sup>+</sup>[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]<sup>−</sup> (<b>5</b>). Complex <b>5</b> initiates the isoprene polymerization, resulting in the quantitative monomer-to-polymer conversion within 1 h. The synthesized polyisoprene contains 59.1% of <i>trans</i>-1,4 units and has <i>M</i><sub>n</sub> = 4.78 · 10<sup>3</sup> and a narrow molecular weight distribution (<i>M</i><sub>w</sub>/<i>M</i><sub>n</sub> = 1.65).</p>

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Scandium and neodymium dichloride complexes with Ph3EO ligands (E = C, Si): synthesis, structure, and catalytic activity in isoprene polymerization

  • 期刊论文

  • 发表日期：

    2025年2月1日

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  • A. O. Tolpygin,
  • T. A. Kovylina,
  • A. V. Cherkasov,
  • G. K. Fukin,
  • A. M. Ob’edkov,
  • A. A. Trifonov

摘要

The reaction of equimolar amounts of ScCl3 and [Ph3EOLi] (E = C, Si) afforded the monomeric dichloride complexes Ph3EOScCl2(THF)3 (E = C (1), Si (2)) in 78 and 81% yields, respectively. The reaction of NdCl3 with [Ph3COLi] gave the dimeric dichloride ate complex [Ph3CONd(THF){(μ-Cl)2Li(THF)2}μ-Cl]2 (3). Under similar conditions, the reaction of NdCl3 with [Ph3SiOLi] afforded the dimeric neodymium monochloride complex [(Ph3SiO)2Nd(THF)2(μ-Cl)]2 (4) regardless of the ratio of the reagents. Complexes 1–4 involved in the two- and three-component catalytic systems (1–4)—[Ph3C][B(C6F5)4] (1: 1) and (1–4)—AlBui3—[Ph3C][B(C6F5)4] (1: 10: 1) initiate the polymerization of isoprene (IP) at room temperature and provide the 14–100% monomer-to-polymer conversion ([IP]/[Ln] = 1000) within 1 to 24 h. The synthesized polymer samples have predominantly a trans-1,4 structure (59.1–80.6%), a low number-average molecular weight (Mn = 0.71–12.71 · 103), and a relatively broad molecular weight distribution (Mw/Mn = = 1.90–4.01). The reaction of complex 1 with [Ph3C][B(C6F5)4] (1: 1) gave the cationic dichloride complex [ScCl2(THF)4]+[B(C6F5)4]− (5). Complex 5 initiates the isoprene polymerization, resulting in the quantitative monomer-to-polymer conversion within 1 h. The synthesized polyisoprene contains 59.1% of trans-1,4 units and has Mn = 4.78 · 103 and a narrow molecular weight distribution (Mw/Mn = 1.65).