Reactivity of [HC{(C(Me)N(Dipp))}2Ca{N(SiMe3)2}(THF)] (Dipp=C6H3iPr2-2,6) with C–H acids: Synthesis of heteroleptic calcium η5-organometallics

Avent, Anthony G.; Crimmin, Mark R.; Hill, Michael S.; Hitchcock, Peter B.

doi:10.1016/j.jorganchem.2005.11.065

Cited by 26 publications

(16 citation statements)

References 28 publications

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“…Capping of K + cations with an η 6 ‐C 6 H 6 ligand is frequently observed but distances are generally longer (3.25–3.45 Å range) . This contrasts with the crystal structure of [( DIPP BDI)K] ∞ which forms a linear zig‐zag coordination polymer with K ··· DIPP contacts in the solid state . On account of similar ionic radii for Ba 2+ and K + (six‐coordinate: Ba 2+ 1.36 Å, K + 1.38 Å) the structures of ( Anth DPM)BaN′′ and ( Anth DPM)K · (C 6 H 6 ) 2 are to some extent comparable.…”

Section: Resultsmentioning

confidence: 95%

Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand

2019

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A new dipyrromethene ligand with 9‐anthracenyl substituents for steric shielding of the metal has been introduced. The ligand, AnthDPM‐H (3), was directly deprotonated with MN′′2 {M = Mg, Ca, Sr, Ba, Zn; N′′ = N(SiMe3)2} to give (AnthDPM)MN′′ (4–8) in the form of highly fluorescent substances that are intensively colored from deep‐red to purple. Crystal structures reveal in all cases monomeric complexes with tricoordinate metals. Also the crystal structure of (AnthDPM)K, prepared by reaction of 3 with KN′′, is presented. The metal's coordination sphere in complexes 4–8 is further saturated by anagostic M···MeSi interactions which are most important for the smaller metals Mg and Zn. For the larger metals, Ca–Ba, the anthracenyl‐substituents assist in metal coordination. These secondary metal π‐interactions result in very high thermal stabilities. The least stable complex (AnthDPM)BaN′′ decomposes at circa 100 °C. The dipyrromethene complexes are clearly more stable than the corresponding β‐diketiminate complexes (DIPPBDI)MN′′ {DIPPBDI = CH[C(Me)N‐DIPP]2, DIPP =2,6‐diisopropylphenyl} which partially decompose at room temperature. These heteroleptic complexes of similar constitution, with metals ranging from Mg to Ba, form a new series that is potentially useful for investigations towards metal effects in early main group metal catalysis.

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Section: Resultsmentioning

confidence: 95%

Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand

2019

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“…Furthermore, potassium phenyl carbon distances suggest that the cation is η 2 ‐(K1−C30 3.467(2) Å, K1−C31 3.224(2) Å) and η 3 ‐coordinated (K1−C23 3.314(2) Å, K1−C27 3.503(2) Å, K1−C28 3.236(2) Å) by one phenyl residue of each benzhydryl group (A search in the CCDC version 5.41 (Aug. 2020) [30] for structures with K and phenyl groups excluding η 6 ‐coordinated ones provided a range of short contacts between K and C ortho of 2.77 to 3.76 Å) [29c,30] . In addition, a toluene molecule is capping the cation in a η 3 ‐fashion (K1−C43 3.344(2) Å, K1−C44 3.098(2) Å, K1−C45 3.152(2) Å) which prevents the formation of a coordination polymer, frequently observed for related potassium complexes based on I–IV [16a,b,d] or H Dipp NacNac [31] …”

Section: Resultsmentioning

confidence: 96%

Bis(4‐benzhydryl‐benzoxazol‐2‐yl)methane – from a Bulky NacNac Alternative to a Trianion in Alkali Metal Complexes

Kretsch

Kreyenschmidt

Schillmöller

et al. 2021

Chemistry A European J

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A novel sterically demanding bis(4‐benzhydryl‐benzoxazol‐2‐yl)methane ligand 6 (4−BzhH2BoxCH2) was gained in a straightforward six‐step synthesis. Starting from this ligand monomeric [M(4‐BzhH2BoxCH)] (M=Na (7), K (81)) and dimeric [{M(4‐BzhH2BoxCH)}2] (M=K (82), Rb (9), Cs (10)) alkali metal complexes were synthesised by deprotonation. Abstraction of the potassium ion of 8 by reaction with 18‐crown‐6 resulted in the solvent separated ion pair [{(THF)2K@(18‐crown‐6)}{bis(4‐benzhydryl‐benzoxazol‐2‐yl)methanide}] (11), including the energetically favoured monoanionic (E,E)‐(4‐BzhH2BoxCH) ligand. Further reaction of 4−BzhH2BoxCH2 with three equivalents KH and two equivalents 18‐crown‐6 yielded polymeric [{(THF)2K@(18‐crown‐6)}{K@(18‐crown‐6)K(4‐BzhBoxCH)}]n (n→∞) (12) containing a trianionic ligand. The neutral ligand and herein reported alkali complexes were characterised by single X‐ray analyses identifying the latter as a promising precursor for low‐valent main group complexes.

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“…Alkaline earth metal silyl amides are one of the most commonly used classes of polar organometallic reagents in organic synthesis including catalytic transformations, enolization reactions, hydroamination reactions and carbon dioxide fixation [2,26,29,[45][46][47][48][49][50][51]. The alkaline earth metal silyl amides serve as versatile reagents in organic synthesis, while the heavier congeners have provided a long sought access to a range of heavy alkaline earth metal derivatives [2,12].…”

Section: Secondary Silylated Aminesmentioning

confidence: 99%

Advances in alkaline earth-nitrogen chemistry

Torvisco

O'Brien

Ruhlandt‐Senge

2011

Coordination Chemistry Reviews

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Reactivity of [HC{(C(Me)N(Dipp))}2Ca{N(SiMe3)2}(THF)] (Dipp=C6H3iPr2-2,6) with C–H acids: Synthesis of heteroleptic calcium η5-organometallics

Cited by 26 publications

References 28 publications

Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand

Stabilization of Heteroleptic Heavier Alkaline Earth Metal Complexes with an Encapsulating Dipyrromethene Ligand

Bis(4‐benzhydryl‐benzoxazol‐2‐yl)methane – from a Bulky NacNac Alternative to a Trianion in Alkali Metal Complexes

Advances in alkaline earth-nitrogen chemistry

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