Calcium, Strontium, and Barium Acetylides—New Evidence for Bending in the Structures of Heavy Alkaline Earth Metal Derivatives

Abstract

An unprecedented ligand bending mode is displayed by the acetylide ligands in the first structurally characterized σ-bound organometallic strontium and barium complexes [M([18]crown-6)(CCSiPh ) ] (M=Sr, Ba). Furthermore, the observed decrease of the angle at the sp-hybridized C atom on descending Group 2 (see structures depicted) affords new information that will lead to a better understanding of the bonding in alkaline earth metal compounds.

Not Just Heavy “Grignards”: Recent Advances in the Organometallic Chemistry of the Alkaline Earth Metals Calcium, Strontium and Barium

“…The first examples of homoleptic heavy alkaline earth metal acetylides were reported recently; [46] these examples are summarized in Table 3.…”

Barium Triphenylmethanide: An Examination of Anion Basicity

“…(1)]. [6] [Ba{N(SiMe 3 ) 2 } 2 (thf) 2 ] 2 HCPh 3 À3 18crown-6Y THF [Ba(CPh 3 ) 2 ([18]crown-6)] 2 HN(SiMe 3 ) 2 (1)However, this reaction did not afford the target compound. Rather, the product of an ether-cleavage reaction was obtained, the novel heteroleptic vinyl ether amide 1 [Eq.…”

Group 2 Mediated Dehydrocoupling

“…Indeed, the activity of Group 2 amides and alkyls with alcohols, pyrroles, terminal alkynes, phosphines and C-H acidic heterocycles has been shown to yield alkoxide, [61][62][63] pyrrolide, 64 acetylide, [65][66][67][68] phosphide [69][70][71][72] and carbanion 73 fragments bound to a Group 2 centre alongside the respective protonated fragment; in the case of metal hexamethyldisilazides (IIa-d) this is an amine, as summarised in Scheme 1.3. …”