Synthetically Important Alkali‐Metal Utility Amides: Lithium, Sodium, and Potassium Hexamethyldisilazides, Diisopropylamides, and Tetramethylpiperidides

Mulvey, Robert E.; Robertson, Stuart D.

doi:10.1002/anie.201301837

Cited by 190 publications

(175 citation statements)

References 137 publications

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“…11 [Ln(N″) 3 ] (Ln = lanthanide) complexes exhibit a zero dipole moment in solution, indicating that they are trigonal planar in this phase, 10g and the scandium homologue, [Sc(N″) 3 ], is trigonal planar in the gas phase and pyramidal in the solid state, which is attributed to crystal packing effects. 12 Germane to this discussion, the related Ln(II) "ate" complexes [MLn(μ-N″) 2 examples of low-coordinate f-block complexes, which tend to favor high coordination numbers due to their relatively large ionic radii and predominantly electrostatic bonding regimes. 14 The pyramidal geometries of these complexes are predicted by both covalent arguments, involving metal nd-orbital participation or dispersive effects, 9b,15 and electrostatics, with the dipole formed by deviation of the cation from the N 3 mean plane resulting in net stabilization.…”

Section: ■ Introductionmentioning

confidence: 98%

Homoleptic Trigonal Planar Lanthanide Complexes Stabilized by Superbulky Silylamide Ligands

et al. 2015

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The lithium silylamides [Li(μ 3 -NHSiMe 2 Bu t )] 6 (1) and [Li(μ-NHSiPr i 3 )(THF)] 2 (2) were reacted with ClSiMe 3 , ClSiMe 2 Bu t , or ClSiPr i 3 to prepare a series of secondary silylamines by salt metathesis reactions. These were deprotonated with KH to afford the group 1 transfer agents [K{μ-N(SiMe 2 Bu t )(SiMe 3 )}(C 7 H 8 )] 2 (3), [{K[μ-N(SiPr i 3 )(SiMe 3 )]} 2 ] ∞ (4), [{K[μ-N(SiMe 2 Bu t ) 2 ]} 2 (C 7 H 8 )] ∞ (5), [K{N(SiPr i 3 )(SiMe 2 Bu t )}] ∞ (6), [K{N(SiPr i 3 ) 2 }] ∞ (7), and [K{N(SiPr i 3 ) 2 }(THF) 3 ] (8). The synthetic utility of these group 1 transfer agents has been demonstrated by their reactions with [Ln(I) 3 (THF) 4 ] (Ln = La, Ce) in various stoichiometries to yield heteroleptic [La{N(SiMe 2 Bu t )(SiMe 3 )} 2 (μ-I)] 2 (9) and homoleptic [Ln{N(SiMe 2 Bu t )(SiMe 3 )} 3 ] (Ln = La 10, Ce 11) and [La{N(SiMe 2 Bu t ) 2 } 3 ] (12). The very bulky silylamide ligands described herein can impart unusual geometries to their lanthanide complexes. Complexes 10−12 remarkably exhibit approximate planarity in the solid state rather than the more common trigonal pyramidal shapes observed in previously reported neutral homoleptic lanthanide silylamide complexes. Complexes 1−12 have been variously characterized by X-ray crystallography, NMR spectroscopy, FTIR spectroscopy, and CHN microanalysis. ■ INTRODUCTIONBulky monodentate alkali metal secondary amides have been employed ubiquitously in diverse research fields. 1 This can in part be attributed to their utility as strong bases, with favorable properties including relatively low nucleophilicity and ease of handling, commercial availability of precursors, and high solubility in hydrocarbon solvents. 2 Of these reagents, the silylamide {N(SiMe 3 ) 2 } − (N″) has received considerable attention as both a base and a ligand since the disclosure of synthetic routes to HN″, 3 LiN″, 4 NaN″, 5 and KN″. 5 The group 1 transfer agents have been widely used to prepare homoleptic three-coordinate p-, d-, and f-block complexes of the general formula [M III (N″) 3 ], as the bulky silyl groups engender low coordination numbers, even for relatively large M III cations. These coordinatively unsaturated complexes can exhibit interesting reactivity profiles. 6 In the solid state, these complexes are trigonal planar D 3h for group 13 (M = Al, Ga, In, Tl) 7 and the first-row transition metals (Ti−Co) 8 and trigonal pyramidal C 3v for group 15 (M = P, As, Sb, Bi), 9 lanthanides (M = Sc, Y, La, Ce−Lu; the group 3 metals are included as lanthanide mimics), 10 and actinides (M = U, Pu). 11 [Ln(N″) 3 ] (Ln = lanthanide) complexes exhibit a zero dipole moment in solution, indicating that they are trigonal planar in this phase, 10g and the scandium homologue, [Sc(N″) 3 ], is trigonal planar in the gas phase and pyramidal in the solid state, which is attributed to crystal packing effects. 12 Germane to this discussion, the related Ln(II) "ate" complexes [MLn(μ-N″) 2 (N″)] (M = Li, Na, K; Ln = Sm, Eu, Yb) 13 exhibit approximately trigonal planar geometries about the lanthani...

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Section: ■ Introductionmentioning

confidence: 98%

Homoleptic Trigonal Planar Lanthanide Complexes Stabilized by Superbulky Silylamide Ligands

et al. 2015

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“…Although less prevalent throughout organometallic chemistry than HMDS, 49 amido DPA has been utilised in a number of varied branches of chemistry 50 including materials science, 51 catalysis, 52 supramolecular chemistry 53 and even in cooperative bimetallic chemistry. 54 Being the simplest of the DPA through three N sites; one central amido N and two neutral pyridyl N atoms.…”

Section: Introductionmentioning

confidence: 99%

Synthetic, structural and magnetic implications of introducing 2,2′-dipyridylamide to sodium-ferrate complexes

et al. 2017

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This version is available at https://strathprints.strath.ac.uk/60604/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. Using a transamination approach to access novel Fe(II) complexes, this study presents the synthesis, X-ray crystallographic and magnetic characterisation of a series of new iron complexes containing the multifunctional 2,2-dipyridylamide (DPA) ligand using iron bis(amide) [{Fe(HMDS)2}2] and sodium ferrate [{NaFe(HMDS)3} ] (1) as precursors (HMDS = 1,1,1,3,3,3hexamethyldisilazide). Reactions of DPA(H) with 1 show exceptionally good stoichiometric control, allowing access to heteroleptic [(THF)2·NaFe(DPA)(HMDS)2] (3) and homoleptic [{THF·NaFe(DPA)3} ] (4) by using 1 and 3 equivalents of DPA(H) respectively. Linking this methodology and co-complexation, which is a more widely used approach to prepare heterobimetallic complexes, 3 can also be prepared by combining NaHMDS with heteroleptic [{Fe(DPA)(HMDS)}2] (2). In turn, 2 has been also synthesised and structurally defined by reacting [{Fe(HMDS)2}2] with two equivalents of DPA(H). Structural studies demonstrate the coordination flexibility of the N-bridged bis(heterocycle) ligand DPA, with 2 and 3 exhibiting discrete monomeric motifs, whereas 4 displays a much more intricate supramolecular structure, with one of its DPA ligands coordinating in an anti/anti fashion (as opposed to 2 and 3 where DPA shows a syn/syn conformation), which facilitates propagation of the structure via its central amido N. Magnetic studies confirmed the high-spin electron configuration of the iron(II) centres in all three compounds and revealed the existence of weak ferromagnetic interactions in dinuclear compound 2 (J = 1.01 cm -1 ). Journal Name ARTICLE

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“…[1] Der einfachste WegzuA ryllithiumreagentien führt entweder über einen Halogen-Lithium-Austausch oder die direkte Metallierung. [2] Gewçhnlich stellt das Vorhandensein einer dirigierenden Gruppe die Lithiierung in der ortho-Position sicher,i mF all von unsymmetrischen Substraten von Typ 1 kann allerdings ein Gemisch der regioisomeren Aryllithiumverbindungen 2 und 3 erhalten werden. [3] Die Bildung solcher Gemische erschwert die Anwendungen in Synthesen ungemein.…”

Section: Organolithiumreagentien Sind Wichtige Metallorganischeunclassified

“…Das Problem fehlender Regioselektivität kçnnte mçglicherweise durch eine bevorzugte Tr ansmetallierung eines der beiden Regioisomere 2 und 3 gelçst werden. Hierfür stellten wir uns vor,dass eine selektive Tr ansmetallierung der sterisch weniger gehinderten Aryllithiumverbindung 3 mit einer entsprechenden Metallverbindung (M-X) selektiv das neue metallierte Aren 4 erzeugt, während die sterisch stärker gehinderte Aryllithiumverbindung (2) . [5] Die Metallierung von 9 mit nBuLi-TMEDA( 1.1 ¾quiv., À80 8 8C, 3h)l ieferte ein 4:1-Gemisch der regioisomeren 2-und 6-lithiierten Derivate.…”

Section: Organolithiumreagentien Sind Wichtige Metallorganischeunclassified

Funktionalisierung von Aryllithium‐Regioisomerengemischen durch selektive Abfangreaktionen mit Zirconocendichlorid

et al. 2015

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Synthetically Important Alkali‐Metal Utility Amides: Lithium, Sodium, and Potassium Hexamethyldisilazides, Diisopropylamides, and Tetramethylpiperidides

Cited by 190 publications

References 137 publications

Homoleptic Trigonal Planar Lanthanide Complexes Stabilized by Superbulky Silylamide Ligands

Homoleptic Trigonal Planar Lanthanide Complexes Stabilized by Superbulky Silylamide Ligands

Synthetic, structural and magnetic implications of introducing 2,2′-dipyridylamide to sodium-ferrate complexes

Funktionalisierung von Aryllithium‐Regioisomerengemischen durch selektive Abfangreaktionen mit Zirconocendichlorid

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