title: Halide-free diarylcalcium complexes--syntheses, structures, and stability.
abstract: A general procedure was developed for the synthesis of diarylcalcium complexes by addition of KOtBu to arylcalcium iodides in THF. Intermediate arylcalcium tert-butanolate dismutates immediately leading to insoluble tert-butanolate precipitates of calcium. Depending on the steric demand and denticity of additional neutral aliphatic azabases, mononuclear or dinuclear complexes trans-[Ca(α-Naph)2(thf)4] (1), [Ca(β-Naph)2(thf)4] (2), [Ca(Tol)2(tmeda)]2 (3), [Ca(Ph)2 (tmeda)]2 (4), [Ca(Ph)2(pmdta)(thf)] (5), [Ca(hmteta)(Ph)2] (6), and [Ca([18]C-6)(Ph)2] (7) were isolated (Naph=naphthyl; meda=N,N,N',N'-tetramethylethylenediamine; pmdta= N,N,N',N'',N''-pentamethyldiethylenetriamine; hmteta=N,N,N',N'',N''',N'''-hexamethyltriethylenetetramine). The Ca-C bond lengths vary between 250.8 and 263.5 pm, the ipso-carbon atoms show low-field-shifted resonances in the (13) C NMR spectra.
authors: Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena (Germany), Fax: (+49)4 3641-948132.
authors: Jens
authors: J
authors: Langer
authors: Mathias
authors: M
authors: Köhler
authors: Helmar
authors: H
authors: Görls
authors: Matthias
authors: M
authors: Westerhausen
keywords: N ligands; Schlenk-type equilibrium; calcium; diarylcalcium; direct synthesis