Synthesis and Reactivity of Discrete Calcium Imides

Abstract

Protonolysis of dibenzylcalcium with triphenylsilylamine affords a thf-coordinated tetrametallic calcium imide with a heterocuboid core structure. The use of calcium bis(tetramethylaluminate) as a precursor for tandem salt metathesis/protonolysis reactions with alkali metal amides of 2,6-diisopropylaniline and triphenylsilylamine provides access to Lewis acid stabilized monocalcium imides of the type [(thf) Ca(μ -NR)(μ -Me)AlMe ]. Treatment of [(thf) Ca(μ -NSiPh )(μ -Me)AlMe ] with phenylsilane results in H-Si addition across the Ca-N imido bond, producing a homoleptic calcium amidoaluminate complex and putative CaH whereas reaction with phenylacetylene leads to protonation of an AlMe moiety to yield the dimeric complex [(thf)Ca{NSiPh }{AlMe (CCPh)}] .

Rare‐Earth Metal Diimide Complexes via Alkylaluminate Templating, Including a Ceric Derivative

“…[26] For comparison, the reaction of the calcium organoimide complex [(thf) 4 Ca(m 2 -NSiPh 3 ){(m 2 -Me)(AlMe 2 )}] with PhCCH did not lead to protonation of the imido moiety but to instant methane evolution andf ormationo ft he dimeric complex [(thf)Ca{NSiPh 3 }{AlMe 2 (CCPh)}] 2 . [27] Monitoring the reaction of (5) ) [28f] The lanthanum centers in 5 are 7-coordinate by three bridging hydrido ligands, the imido nitrogen and three thf donors with LaÀHb ond lengths of 2.31(3) and 2.53 (3) . Most unfortunately,u pscaling the 1-La/PhSiH 3 reaction in a1 :2 ratio led to even more complicated mixtures.…”

Chasing Multiple Bonding Interactions between Alkaline‐Earth Metals and Main‐Group Fragments

“…Employing calcium bis(tetramethylaluminate)[ Ca(AlMe 4 ) 2 ] n and alkali-metal amides [A{NH(R)}] (A = Li, K) in salt-metathesisprotonolysisr eaction sequences, monomeric calcium-imide species[ (thf) 4 Ca(m-NR)(m-Me)AlMe 2 ]( R= SiPh 3 , 24;R= Dipp, 25; Figure 4) could be obtained, which can be described as Lewisacid (AlMe 3 )-stabilized calcium imides. [136] Interestingly and contrary to the reaction of dibenzylcalcium with H 2 NDipp (vide supra) in this case the Dipp backbone allowed for as econd deprotonation, yieldingh eterobimetallic imide 25.W hen sterically lessd emanding amides were employed, dimericc ompounds [(thf) 2 Ca(NR)(AlMe 3 )] 2 (R = Ph, 26;R= C 6 H 3 Me 2 -3,5, 27;F igure 4) along with highera ggregated imides [(thf) x Ca 3 (NR) 4 (AlMe 2 ) 2 ] (R = Ph, x = 6, 28;R = C 6 H 3 Me 2 -3,5, x = 5, 29;F igure 4) were formed. [137] The reactivity of Ae imides was extensively examined for compound [(thf)Mg(NPh)] 6 (13,S cheme 6).…”

“…[128,[138][139][140] Scheme7.Reactivity of AlMe 3 -stabilized Ca II -imide 24 toward phenylsilane (H 3 SiPh), 2,6-di-tert-butyl-4-methylphenol( bht),a nd phenylacetylene (PhCCH). [136,137] typical imide reactivity (H 3 SiPh) and the non-innocent behavior of the coordinated Lewis acid AlMe 3 (bht and PhCCH). [136,137]…”

“…[136,137] typical imide reactivity (H 3 SiPh) and the non-innocent behavior of the coordinated Lewis acid AlMe 3 (bht and PhCCH). [136,137]…”

Lewis‐Acid Stabilized Organoimide Complexes of Divalent Samarium, Europium, and Ytterbium

“…[28,29] We reasoned that Ln II imides might be of particulari nterest for targeted redox approaches to imide derivatives which are not accessible from Ln III precursors. Recently,w ew ere ablet os ynthesize Lewis-acid stabilized Ca II imide complexes by tandems alt metathesis-protonolysis reactions of bis(tetramethylaluminate)[ Ca(AlMe 4 ) 2 ] n and alkali metal amides. [30] Considering the similarities of Ca II and Ln II with regard to their ionic radii and ionic bonding, and in particular Yb II , [31] we wereinterested to probe the feasibility of this synthesis protocol for the divalent rare-earth metals. Herein, we report on the successful synthesis, characterization, and redox behavioro fL ewis-acid stabilized Ln II imide complexes of the type [(thf) x Ln(NR)(AlMe 3 )] y (Ln = Sm, Eu, Yb).…”