Dimethyl-, diphenyl- and cyclotetramethylene silylchloride derivatives of guanidine, their synthesis and structure. Formation of pentacoordinated silicon compounds and an unexpected diionic disila-diguanidinium dichloride

Maaranen, Janne; Andell, Ove S.; Vanne, Tiina; Mutikainen, Ilpo

doi:10.1016/j.jorganchem.2005.09.002

Cited by 12 publications

(5 citation statements)

References 31 publications

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“…The distances of the N(1)−C(1) and N(2)−C(1) bonds are in the typical C−N single-bond range. The average Si−N distance of 1.735(3) Å is comparable to the values found in [{Ln(η 2 -C 3 N 2 HMe 2 -3,5)(μ-η 1 :η 2 -OSiMe 2 C 3 N 2 HMe 2 -3,5)(η-C 5 H 4 Me)} 2 ] (Ln = Yb, Dy), 1.792(6) Å, but is significantly shorter than the Si−N donor bond distances …”

Section: Resultssupporting

confidence: 77%

Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp₂Ln[(CyN)₂CNPh]Li(THF)₃

Zheng¹,

Hong²,

Liu³

et al. 2010

Organometallics

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The treatment of Cp3Ln with 1 equiv of N,N′-dicyclohexyl-N′′-phenylguanidine followed by reacting with butyllithium yields a series of novel guanidinate dianion complexes of heterobimetallic lanthanide−lithium with formula Cp2Ln[(CyN)2CNPh]Li(THF)3 (Ln = Yb (1a), Er (1b), Y (1c), Dy (1d)). Reactivities of these dianionic guanidinate complexes toward various electrophiles have been investigated. Reaction of 1 with Me2RSiCl produced tetrasubstituted guanidinate monoanion complexes Cp2Ln[(CyN)2CN(Ph)SiRMe2] ((R = Me, Ln = Yb (2a), Er (2b), Y (2c); R = t Bu, Ln = Yb (3a), Er (3b)), indicating that the Li−N bond is preferred to couple with chlorosilanes. In contrast, the regioselective functionalization of the NCy group bonded to the lanthanide ion was achieved by reaction of 1a with Me2SiCl2 to produce Me2Si(CyN)2CNPh (4) and Cp2YbCl(THF) (5). Significantly, treatment of 1d with PhCOCl leads to the cleavage of one C−N bond of the dianionic guanidinate, giving the acylamino complex [Cp2Dy(OC(Ph)NCy)]2 (6). These results have shown that the active site of the dianionic guanidinate ligand is tunable due to the delocalization of the two negative charges on the three N atoms. All the compounds were characterized by elemental analysis and spectroscopic methods. The structures of compounds 1−6 are also determined through X-ray single-crystal diffraction analysis.

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Section: Resultssupporting

confidence: 77%

Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp₂Ln[(CyN)₂CNPh]Li(THF)₃

Zheng¹,

Hong²,

Liu³

et al. 2010

Organometallics

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“…Following the procedure developed by Andell and co-workers, the hypervalent chlorosilane 1 was isolated from [K + ,TBD – ] and Me 2 SiCl 2 . Replacing Me 2 SiCl 2 with i -Pr 2 SiCl 2 and Ph 2 SiCl 2 led to the isolation of the analogous compounds i Pr 1 and Ph 1 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Implications of CO₂ Activation by Frustrated Lewis Pairs in the Catalytic Hydroboration of CO₂: A View Using N/Si⁺ Frustrated Lewis Pairs

et al. 2016

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A series of base-stabilized silylium species were synthesized and their reactivity toward CO 2 explored, yielding the characterization of a novel N/ Si + FLP-CO 2 adduct. These silicon species are active catalysts in the hydroboration of CO 2 to the methoxide level with 9-BBN, catecholborane (catBH), and pinacolborane (pinBH). Both experiments and DFT calculations highlight the role of the FLP-CO 2 adduct in the catalysis. Depending on the nature of the hydroborane reductant, two distinct mechanisms have been unveiled. While 9-BBN and catBH are able to reduce an intermediate FLP-CO 2 adduct, the hydroboration of CO 2 with pinBH follows a different and novel path where the B−H bond is activated by the silicon-based Lewis acid catalyst. In these mechanisms, the formation of a highly stabilized FLP-CO 2 adduct is found detrimental to the kinetics of the reaction.

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“…For the synthesis of the TBD-stabilized silylium complexes, Cantat et al followed the procedure developed by Andell and co-workers. 33 Given the generality of the method, 34 it is reasonable to expect that the present stannylium complexes can also be prepared analogously.…”

Section: ■ Introductionmentioning

confidence: 98%

“…Inspired by this, we have examined intramolecular Sn/N FLPs featuring the TBD backbone to extract a similar reactivity out of it. For the synthesis of the TBD-stabilized silylium complexes, Cantat et al followed the procedure developed by Andell and co-workers . Given the generality of the method, it is reasonable to expect that the present stannylium complexes can also be prepared analogously.…”

Section: Introductionmentioning

confidence: 99%

Computational Exploration of Intramolecular Sn/N Frustrated Lewis Pairs for Hydrogen Activation and Catalytic Hydrogenation

Das

Pati

2021

Organometallics

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Stannylium-based cationic Lewis acids (LAs) are gaining attention as an alternative to neutral boranes for their use in frustrated Lewis pair (FLP)mediated hydrogenation catalysis. Although intermolecular FLP combinations of stannylium LAs and nitrogen-Lewis bases are studied in detail, reports on their intramolecular analogs are lacking at present. In this work, through density functional theory calculations, we investigate a family of intramolecular stannylium/nitrogen FLPs (1-R-X) for their ability to activate dihydrogen and subsequently perform catalytic hydrogenation of organic compounds with unsaturated functional groups. These FLPs are designed by embedding stannylium motifs into a cyclic guanidinate backbone that provides a complementary Lewis basic nitrogen site. By varying the substituents and the counter anion on the Sn center, we show how to significantly tune the reactivity of this family of FLPs. The mechanism of H 2 activation by 1-R-X is elucidated in detail, and we find that the heterolytic cleavage of the H−H bond proceeds through cooperative action of the Sn and N centers. The energetics of the H 2 cleavage is correlated with molecular descriptors to understand trends in reactivity and to easily filter candidates suitable for the hydrogen release step necessary to complete the hydrogenation cycle. Finally, we find that the release of the proton and the hydride from the Lewis centers to multiple bonds occur in a concerted manner enabling catalytic hydrogenation of the corresponding organic substrates.

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Dimethyl-, diphenyl- and cyclotetramethylene silylchloride derivatives of guanidine, their synthesis and structure. Formation of pentacoordinated silicon compounds and an unexpected diionic disila-diguanidinium dichloride

Cited by 12 publications

References 31 publications

Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp₂Ln[(CyN)₂CNPh]Li(THF)₃

Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp₂Ln[(CyN)₂CNPh]Li(THF)₃

Implications of CO₂ Activation by Frustrated Lewis Pairs in the Catalytic Hydroboration of CO₂: A View Using N/Si⁺ Frustrated Lewis Pairs

Computational Exploration of Intramolecular Sn/N Frustrated Lewis Pairs for Hydrogen Activation and Catalytic Hydrogenation

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Dimethyl-, diphenyl- and cyclotetramethylene silylchloride derivatives of guanidine, their synthesis and structure. Formation of pentacoordinated silicon compounds and an unexpected diionic disila-diguanidinium dichloride

Cited by 12 publications

References 31 publications

Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp2Ln[(CyN)2CNPh]Li(THF)3

Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp2Ln[(CyN)2CNPh]Li(THF)3

Implications of CO2 Activation by Frustrated Lewis Pairs in the Catalytic Hydroboration of CO2: A View Using N/Si+ Frustrated Lewis Pairs

Computational Exploration of Intramolecular Sn/N Frustrated Lewis Pairs for Hydrogen Activation and Catalytic Hydrogenation

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Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp₂Ln[(CyN)₂CNPh]Li(THF)₃

Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp₂Ln[(CyN)₂CNPh]Li(THF)₃

Implications of CO₂ Activation by Frustrated Lewis Pairs in the Catalytic Hydroboration of CO₂: A View Using N/Si⁺ Frustrated Lewis Pairs