Organomagnesium clusters: Structure, stability, and bonding in archetypal models

Jiménez‐Halla, J. Óscar C.; Bickelhaupt, F. Matthias; Solà, Miquel

doi:10.1016/j.jorganchem.2011.06.014

Cited by 15 publications

(12 citation statements)

References 68 publications

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“…The polymerization reaction proceeds under reversible chain transfer conditions that involve association/dissociation of a dialkylmagnesium with the neodymocene active catalyst. ,, Thereof, the magnesium species play a crucial role in the polymerization and must be included in the chemical model . In toluene solution, the cluster Mg 4 (σ- n -Bu) 2 (μ- n -Bu) 4 (μ 3 - n -Bu) 2 , in which two alkyl chains are terminal, four are bridging, and two are facial, was calculated as the most relevant and stable aggregate. ,, In this study, as an unsaturation is present on the CTA, and as Bu 2 O is used as a cosolvent by default, a hand sampling of the magnesium clusters has been carried out. Bu 2 O affect sthe magnesium cluster by displacing Mg···(CC) interactions and also by dissociating tetramers into the most stable cosolvated dimers Mg 2 R 4 ·(Bu 2 O) 2 , as previously discussed (Table S1).…”

Section: Resultssupporting

confidence: 91%

“…In toluene solution, the cluster Mg 4 (σ-n-Bu) 2 (μ-n-Bu) 4 (μ 3 -n-Bu) 2 , in which two alkyl chains are terminal, four are bridging, and two are facial, was calculated as the most relevant and stable aggregate. 14,28,29 In this study, as an unsaturation is present on the CTA, and as Bu 2 O is used as a cosolvent by default, a hand sampling of the magnesium clusters has been carried out. Bu 2 O affect sthe magnesium cluster by displacing Mg•••(CC) interactions and also by dissociating tetramers into the most stable cosolvated dimers Mg 2 R 4 •(Bu 2 O) 2 , as previously discussed (Table S1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Dialkenylmagnesium Compounds in Coordinative Chain Transfer Polymerization of Ethylene. Reversible Chain Transfer Agents and Tools To Probe Catalyst Selectivities toward Ring Formation

et al. 2018

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A range of dialkenylmagnesium compounds ([CH2CH(CH2) n ]2Mg; n = 1–6) were synthesized and used as chain transfer agents (CTA) with either (C5Me5)2NdCl2Li(OEt2)2 (1) or [Me2Si(C13H8)2Nd(BH4)2Li(thf)]2 (2) neodymium precursors for the polymerization of ethylene. In all cases, the systems followed a controlled coordinative chain transfer polymerization mechanism. The intramolecular insertion of the vinyl group on the CTA in growing chains is possible and led to the formation of cyclopentyl, cyclohexyl, and possibly cycloheptyl chain ends. While the production of cyclopentyl- or cyclohexyl-capped polyethylene chains can be quantitative (n = 2–5), the integrity of this double bond can also be kept if n is higher than 6. In comparison to 1/CTA catalytic systems, 2/CTA catalytic systems showed a higher propensity to produce cycloalkyl chain ends. This was ascribed to the lower steric demand around the active site, as shown by DFT calculations. In addition, the formation of bis(cyclopentylmethyl)magnesium from dipentenylmagnesium using a catalytic amount of 2 was shown.

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Section: Resultssupporting

confidence: 91%

Section: ■ Results and Discussionmentioning

confidence: 99%

Dialkenylmagnesium Compounds in Coordinative Chain Transfer Polymerization of Ethylene. Reversible Chain Transfer Agents and Tools To Probe Catalyst Selectivities toward Ring Formation

et al. 2018

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“…In both structures, two chlorides at the magnesium atoms show a coordination number of three. Searching the Cambridge Crystallography Database reveals that magnesium chlorides, with a μ-Cl 3 coordination, predominantly form cubic aggregation modes in the solid state. , Bickelhaupt and Solà et al have shown that the most stable isomer of methylmagnesium chloride is a T d -symmetric (CH 3 MgCl) 4 tetranuclear cluster with a cubic (MgCl) 4 core and terminal CH 3 groups at the magnesium vertexes . Li halides are also known to build stable cubic tetramers [LiX] 4 (X = Cl, Br, I) and even heteroleptic cubanes in the solid state (see compound 3 in Figure ).…”

Section: Discussionmentioning

confidence: 99%

Solution Structures of Hauser Base ⁱPr₂NMgCl and Turbo-Hauser Base ⁱPr₂NMgCl·LiCl in THF and the Influence of LiCl on the Schlenk-Equilibrium

et al. 2016

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Grignard reagents that are at the simplest level described as "RMgX" (where R is an organic substituent and X a halide) are one of the most widely utilized classes of synthetic reagents. Lately, especially Grignard reagents with amido ligands of the type R1R2NMgX, so-called Hauser bases, and their Turbo analogue R1R2NMgX·LiCl play an outranging role in modern synthetic chemistry. However, because of their complex solution behavior, where Schlenk-type equilibria are involved, very little is known about their structure in solution. Especially the impact of LiCl on the Schlenk-equilibrium was still obscured by complexity and limited analytical access. Herein, we present unprecedented insights into the solution structure of the Hauser base (i)Pr2NMgCl 1 and the Turbo-Hauser base (i)Pr2NMgCl·LiCl 2 at various temperatures in THF-d8 solution by employing a newly elaborated diffusion ordered spectroscopy (DOSY) NMR method hand-in-hand with theoretical calculations.

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“…121 The bonding in monomers and tetramers of CH 3 MgCl and MgX 2 (X = H, Cl, and CH 3 ) has been studied by DFT calculations. 122 Gas-phase decarboxylation of magnesium acetate crown complex cations has been explored as a means of synthesising the corresponding organomagnesium cations. 123 A one-pot synthesis by direct magnesium insertion in the presence of B(OBu) 3 and LiCl has allowed a broad range of functionalised (hetero)aryl and alkenyl bromides to be converted into magnesium diorganoboronates, which undergo Suzuki-Miyaura cross-coupling reactions.…”

Section: Beryllium and Magnesiummentioning

confidence: 99%

Alkaline and alkaline earth metals

Hill

2012

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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Advances made during the calendar year 2011 relating to the coordination and inorganic chemistry of the elements of Groups 1 and 2 are summarised in this non-critical review. Coverage concentrates on topics centred around the synthesis, and applications of coordination and organometallic compounds of these elements. HighlightsThe isolation and reaction chemistry of kinetically-stabilised Group 2 species in which the alkaline earth centre exists in a formal +1 oxidation state has received intense international attention while interest in the potential of alkaline earth complexes as benign and inexpensive reagents for catalysis has continued to develop. LithiumA review of the resting-state structures of organocuprates determined using X-ray crystallography has appeared. 1 The electronic stability of s-block benzylates and di-and tri-phenylmethanide derivatives has been reviewed. 2 Reactions of the lithium boryl LiB(DippNCHQCHNDipp) with organohalides (RX) giving RB(DippNCHQCHNDipp) have been studied using DFT calculations. 3 Group 14 donor ligands An X-ray diffraction analysis of tetrareduced corannulene, C 20 H 10 4À , has confirmed the formation of a sandwich-type supramolecular aggregate in which five Li + ions are sandwiched between the two tetrareduced corannulene decks. 4 A combined experimental and DFT study has predicted that benzyl anions with strong p-withdrawing groups in the meta position have low energy diradical or triplet electronic states. 5 A lithium complex of an abnormal carbene with the composition [H 3 BC{{N(2, Pr 2 )C 6 H 3 } 2 )CHCLi(THF) 3 }] has been synthesised by lithiation of the NHC borane adduct. 6 Diastereomeric oxazolinylaziridines (R,R)-9 and (R,S)-9 have been regioselectively lithiated at the a-position with respect to the oxazolinyl ring. 7 Computational studies of the carbolithiation of b-methylstyrene with

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Organomagnesium clusters: Structure, stability, and bonding in archetypal models

Cited by 15 publications

References 68 publications

Dialkenylmagnesium Compounds in Coordinative Chain Transfer Polymerization of Ethylene. Reversible Chain Transfer Agents and Tools To Probe Catalyst Selectivities toward Ring Formation

Dialkenylmagnesium Compounds in Coordinative Chain Transfer Polymerization of Ethylene. Reversible Chain Transfer Agents and Tools To Probe Catalyst Selectivities toward Ring Formation

Solution Structures of Hauser Base ⁱPr₂NMgCl and Turbo-Hauser Base ⁱPr₂NMgCl·LiCl in THF and the Influence of LiCl on the Schlenk-Equilibrium

Alkaline and alkaline earth metals

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Organomagnesium clusters: Structure, stability, and bonding in archetypal models

Cited by 15 publications

References 68 publications

Dialkenylmagnesium Compounds in Coordinative Chain Transfer Polymerization of Ethylene. Reversible Chain Transfer Agents and Tools To Probe Catalyst Selectivities toward Ring Formation

Dialkenylmagnesium Compounds in Coordinative Chain Transfer Polymerization of Ethylene. Reversible Chain Transfer Agents and Tools To Probe Catalyst Selectivities toward Ring Formation

Solution Structures of Hauser Base iPr2NMgCl and Turbo-Hauser Base iPr2NMgCl·LiCl in THF and the Influence of LiCl on the Schlenk-Equilibrium

Alkaline and alkaline earth metals

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Solution Structures of Hauser Base ⁱPr₂NMgCl and Turbo-Hauser Base ⁱPr₂NMgCl·LiCl in THF and the Influence of LiCl on the Schlenk-Equilibrium