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Monoanionic triketiminate ligands: Peculiarity of coordination mode to lithium and rare earth ions.

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Title: Monoanionic triketiminate ligands: Peculiarity of coordination mode to lithium and rare earth ions.
Authors: Skvortsov, Grigorii G.1 (AUTHOR), Fukin, Georgy K.1 (AUTHOR), Cherkasov, Anton V.1 (AUTHOR), Kovylina, Tatyana A.1 (AUTHOR), Trifonov, Alexander A.1,2 (AUTHOR) trif@iomc.ras.ru
Source: Inorganica Chimica Acta. Aug2020, Vol. 508, pN.PAG-N.PAG. 1p.
Subjects: Rare earth ions, Rare earth metals, Ligands (Chemistry), Ternary system, Molecular weights
Abstract: • Monoanionic β-triketiminate ligands feature bidentate coordination mode and are coordinated to a metal center only through two nitrogen atoms. • The ternary systems based on these complexes exhibit catalytic activity in isoprene polymerization. • The ternary systems provide very high content of cis -1,4 units (98.9%). Deprotonation of β-triketimines (2,6-Me 2 C 6 H 3 N = CMe) 3 CH (1), (2,6-Me 2 C 6 H 3 N = CMe) 2 CH(2-MeOC 6 H 4 N = C t Bu) (2), (2,6-Me 2 C 6 H 3 N = CMe) 2 CH(2,6-Me 2 C 6 H 3 N = C t Bu) (3) by equimolar amount of n -BuLi afforded lithium triketiminate complexes [(2,6-Me 2 C 6 H 3 N = CMe) 3 C]Li(THF) (4), [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]Li(THF) 2 (5), [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]Li(THF) 2 (6) in 70–80% yields. The salt metathesis reactions of LnCl 3 (Ln = Y, Nd) with 6 lead to the formation of neutral triketiminate dichloro complexes [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]LnCl 2 (THF) 2 (Ln = Y (7), Nd (8)) in 78 and 70% yields, while the analogous reaction of YCl 3 with 5 resulted in triketiminate yttrium chloro ate complex [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]Y(THF)Cl(µ2-Cl) 2 Li(THF) 2 (9). The reactions of the potassium derivatives of the related triketimines 2 , 3 with YbI 2 (THF) 2 resulted in the formation of mononuclear triketiminate iodo Yb(II) complexes [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]YbI(THF) 2 (10) and [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]YbI(TMEDA) (11). X-ray analysis revealed that in 4 and rare-earth metals complexes 7 – 11 the monoanionic β-triketiminate ligands [(2,6-Me 2 C 6 H 3 N = CMe) 3 C]−, [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]−, [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]− feature bidentate coordination mode and are coordinated to a metal center only through two nitrogen atoms. The ternary systems 7–9 /Al i Bu 3 /[CPh 3 [B(C 6 F 5) 4 exhibit catalytic activity in isoprene polymerization, allowing to carry out polymerization of 1000 equivalents in 2 h with 91–100% conversion. The obtained polyisoprenes feature high molecular weights (M n = 12.8 × 104–20.2 × 104) and moderate polydispersities (M w / M n = 2.7–3.6), however excellent control of regio- and stereoselectivities (up to 9.9% cis -1,4 units) was observed. [ABSTRACT FROM AUTHOR]
Copyright of Inorganica Chimica Acta is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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  Data: Monoanionic triketiminate ligands: Peculiarity of coordination mode to lithium and rare earth ions.
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  Data: <searchLink fieldCode="AR" term="%22Skvortsov%2C+Grigorii+G%2E%22">Skvortsov, Grigorii G.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Fukin%2C+Georgy+K%2E%22">Fukin, Georgy K.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Cherkasov%2C+Anton+V%2E%22">Cherkasov, Anton V.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Kovylina%2C+Tatyana+A%2E%22">Kovylina, Tatyana A.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Trifonov%2C+Alexander+A%2E%22">Trifonov, Alexander A.</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> trif@iomc.ras.ru</i>
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– Name: Abstract
  Label: Abstract
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  Data: • Monoanionic β-triketiminate ligands feature bidentate coordination mode and are coordinated to a metal center only through two nitrogen atoms. • The ternary systems based on these complexes exhibit catalytic activity in isoprene polymerization. • The ternary systems provide very high content of cis -1,4 units (98.9%). Deprotonation of β-triketimines (2,6-Me 2 C 6 H 3 N = CMe) 3 CH (1), (2,6-Me 2 C 6 H 3 N = CMe) 2 CH(2-MeOC 6 H 4 N = C t Bu) (2), (2,6-Me 2 C 6 H 3 N = CMe) 2 CH(2,6-Me 2 C 6 H 3 N = C t Bu) (3) by equimolar amount of n -BuLi afforded lithium triketiminate complexes [(2,6-Me 2 C 6 H 3 N = CMe) 3 C]Li(THF) (4), [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]Li(THF) 2 (5), [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]Li(THF) 2 (6) in 70–80% yields. The salt metathesis reactions of LnCl 3 (Ln = Y, Nd) with 6 lead to the formation of neutral triketiminate dichloro complexes [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]LnCl 2 (THF) 2 (Ln = Y (7), Nd (8)) in 78 and 70% yields, while the analogous reaction of YCl 3 with 5 resulted in triketiminate yttrium chloro ate complex [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]Y(THF)Cl(µ2-Cl) 2 Li(THF) 2 (9). The reactions of the potassium derivatives of the related triketimines 2 , 3 with YbI 2 (THF) 2 resulted in the formation of mononuclear triketiminate iodo Yb(II) complexes [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]YbI(THF) 2 (10) and [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]YbI(TMEDA) (11). X-ray analysis revealed that in 4 and rare-earth metals complexes 7 – 11 the monoanionic β-triketiminate ligands [(2,6-Me 2 C 6 H 3 N = CMe) 3 C]−, [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]−, [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]− feature bidentate coordination mode and are coordinated to a metal center only through two nitrogen atoms. The ternary systems 7–9 /Al i Bu 3 /[CPh 3 [B(C 6 F 5) 4 exhibit catalytic activity in isoprene polymerization, allowing to carry out polymerization of 1000 equivalents in 2 h with 91–100% conversion. The obtained polyisoprenes feature high molecular weights (M n = 12.8 × 104–20.2 × 104) and moderate polydispersities (M w / M n = 2.7–3.6), however excellent control of regio- and stereoselectivities (up to 9.9% cis -1,4 units) was observed. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Inorganica Chimica Acta is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
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        Value: 10.1016/j.ica.2020.119623
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        Text: English
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      – SubjectFull: Rare earth ions
        Type: general
      – SubjectFull: Rare earth metals
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      – SubjectFull: Ligands (Chemistry)
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      – SubjectFull: Ternary system
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      – SubjectFull: Molecular weights
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      – TitleFull: Monoanionic triketiminate ligands: Peculiarity of coordination mode to lithium and rare earth ions.
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