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Halide‐Free Diarylcalcium Complexes—Syntheses, Structures, and Stability
Author(s) -
Langer Jens,
Köhler Mathias,
Görls Helmar,
Westerhausen Matthias
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201304429
Subject(s) - halide , chemistry , combinatorial chemistry , organic chemistry
A general procedure was developed for the synthesis of diarylcalcium complexes by addition of KO t Bu 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 CaC 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.