Synthesis, characterization, and reactivity of ansa-bis(allyl) lanthanide complexes, a new class of single-component methyl methacrylate polymerization catalysts

Timothy J. Woodman; Mark Schormann; Manfred Bochmann

doi:10.1021/om0301334

Synthesis, characterization, and reactivity of ansa-bis(allyl) lanthanide complexes, a new class of single-component methyl methacrylate polymerization catalysts

Timothy J. Woodman, Mark Schormann, Manfred Bochmann

Research output: Contribution to journal › Article › peer-review

46 Citations (Scopus)

Abstract

The reaction of the dipotassium salt K₂{3-(C₃H₃SiMe₃-1)₂SiMe₂} with LnCl₃ in THF leads to the formation of the new ansa-allyl lanthanate complexes [Ln{(?³-C₃H₃SiMe₃)₂SiMe₂}₂{µ-K(THF)}·nTHF]₈ (1, Ln = La, n = 0.5; 2, Ln = Y, n = 1; 3, Ln = Sc, n = 1). Reaction of K₂{3-(C₃H₃SiMe₃-1)₂SiMe₂} with NdI₃(THF)_3.5 affords THF-free [Nd{(?³-C₃H₃SiMe₃)₂SiMe₂}₂(µ-K)]₈ (4). Treatment of SmI₂(THF)₂ with Li{3-(C₃H₃SiMe₃-1)₂SiMe₂}/KO^tBu resulted in the samarium(III) complex [Li(OEt₂)₄][Sm{(?³-C₃H₃SiMe₃)₂SiMe₂}₂] (5), albeit in small yield. Whereas the crystal structure of 1 shows a coordination polymer, with potassium bridging to allyl moieties of two neighboring lanthanide units and close K···CH₃Si contacts, complex 5 consists of discrete ions. The complexes 1-5 are all found to be efficient catalysts for the polymerization of methyl methacrylate to high-molecular-weight polymers under a variety of conditions, with 2 at 0 °C giving extremely high turnovers of 86 400 mol of MMA (mol of Y)^-¹ h^-¹.

Original language	English
Pages (from-to)	2938-2943
Number of pages	6
Journal	Organometallics
Volume	22
Issue number	14
DOIs	https://doi.org/10.1021/om0301334
Publication status	Published - 4 Jun 2003

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@article{fd6007d0fb65416e8dbaabfc03a44f61,

title = "Synthesis, characterization, and reactivity of ansa-bis(allyl) lanthanide complexes, a new class of single-component methyl methacrylate polymerization catalysts",

abstract = "The reaction of the dipotassium salt K2{3-(C3H3SiMe3-1)2SiMe2} with LnCl3 in THF leads to the formation of the new ansa-allyl lanthanate complexes [Ln{(?3-C3H3SiMe3)2SiMe2}2{µ-K(THF)}·nTHF]8 (1, Ln = La, n = 0.5; 2, Ln = Y, n = 1; 3, Ln = Sc, n = 1). Reaction of K2{3-(C3H3SiMe3-1)2SiMe2} with NdI3(THF)3.5 affords THF-free [Nd{(?3-C3H3SiMe3)2SiMe2}2(µ-K)]8 (4). Treatment of SmI2(THF)2 with Li{3-(C3H3SiMe3-1)2SiMe2}/KOtBu resulted in the samarium(III) complex [Li(OEt2)4][Sm{(?3-C3H3SiMe3)2SiMe2}2] (5), albeit in small yield. Whereas the crystal structure of 1 shows a coordination polymer, with potassium bridging to allyl moieties of two neighboring lanthanide units and close K···CH3Si contacts, complex 5 consists of discrete ions. The complexes 1-5 are all found to be efficient catalysts for the polymerization of methyl methacrylate to high-molecular-weight polymers under a variety of conditions, with 2 at 0 °C giving extremely high turnovers of 86 400 mol of MMA (mol of Y)-1 h-1.",

author = "Woodman, {Timothy J.} and Mark Schormann and Manfred Bochmann",

year = "2003",

month = jun,

day = "4",

doi = "10.1021/om0301334",

language = "English",

volume = "22",

pages = "2938--2943",

journal = "Organometallics",

issn = "0276-7333",

publisher = "American Chemical Society",

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TY - JOUR

T1 - Synthesis, characterization, and reactivity of ansa-bis(allyl) lanthanide complexes, a new class of single-component methyl methacrylate polymerization catalysts

AU - Woodman, Timothy J.

AU - Schormann, Mark

AU - Bochmann, Manfred

PY - 2003/6/4

Y1 - 2003/6/4

N2 - The reaction of the dipotassium salt K2{3-(C3H3SiMe3-1)2SiMe2} with LnCl3 in THF leads to the formation of the new ansa-allyl lanthanate complexes [Ln{(?3-C3H3SiMe3)2SiMe2}2{µ-K(THF)}·nTHF]8 (1, Ln = La, n = 0.5; 2, Ln = Y, n = 1; 3, Ln = Sc, n = 1). Reaction of K2{3-(C3H3SiMe3-1)2SiMe2} with NdI3(THF)3.5 affords THF-free [Nd{(?3-C3H3SiMe3)2SiMe2}2(µ-K)]8 (4). Treatment of SmI2(THF)2 with Li{3-(C3H3SiMe3-1)2SiMe2}/KOtBu resulted in the samarium(III) complex [Li(OEt2)4][Sm{(?3-C3H3SiMe3)2SiMe2}2] (5), albeit in small yield. Whereas the crystal structure of 1 shows a coordination polymer, with potassium bridging to allyl moieties of two neighboring lanthanide units and close K···CH3Si contacts, complex 5 consists of discrete ions. The complexes 1-5 are all found to be efficient catalysts for the polymerization of methyl methacrylate to high-molecular-weight polymers under a variety of conditions, with 2 at 0 °C giving extremely high turnovers of 86 400 mol of MMA (mol of Y)-1 h-1.

AB - The reaction of the dipotassium salt K2{3-(C3H3SiMe3-1)2SiMe2} with LnCl3 in THF leads to the formation of the new ansa-allyl lanthanate complexes [Ln{(?3-C3H3SiMe3)2SiMe2}2{µ-K(THF)}·nTHF]8 (1, Ln = La, n = 0.5; 2, Ln = Y, n = 1; 3, Ln = Sc, n = 1). Reaction of K2{3-(C3H3SiMe3-1)2SiMe2} with NdI3(THF)3.5 affords THF-free [Nd{(?3-C3H3SiMe3)2SiMe2}2(µ-K)]8 (4). Treatment of SmI2(THF)2 with Li{3-(C3H3SiMe3-1)2SiMe2}/KOtBu resulted in the samarium(III) complex [Li(OEt2)4][Sm{(?3-C3H3SiMe3)2SiMe2}2] (5), albeit in small yield. Whereas the crystal structure of 1 shows a coordination polymer, with potassium bridging to allyl moieties of two neighboring lanthanide units and close K···CH3Si contacts, complex 5 consists of discrete ions. The complexes 1-5 are all found to be efficient catalysts for the polymerization of methyl methacrylate to high-molecular-weight polymers under a variety of conditions, with 2 at 0 °C giving extremely high turnovers of 86 400 mol of MMA (mol of Y)-1 h-1.

U2 - 10.1021/om0301334

DO - 10.1021/om0301334

M3 - Article

VL - 22

SP - 2938

EP - 2943

JO - Organometallics

JF - Organometallics

SN - 0276-7333

IS - 14

ER -