title: Concept for enhancement of the stability of calcium-bound pyrazolyl-substituted methanides.
abstract: Metalation of bis(3-thiophen-2-ylpyrazol-1-yl)phenylmethane [2, which is accessible from the reaction of bis(3-thien-2-ylpyrazol-1-yl)methanone (1) with triphosgene] with [(thf)2Ca{N(SiMe3)2}2] in tetrahydrofuran and subsequent crystallization from a mixture of toluene and 1,2-dimethoxyethane yield [(dme)Ca{C(Pz(th))2Ph}{N(SiMe3)2}] (3). The α,α-bis(3-thiophen-2-ylpyrazol-1-yl)benzyl ligand exhibits a κ(2)N,κC-coordination mode with a Ca-C σ-bond length of 262.8(2) pm. The crystalline compound is stable if air and moisture is strictly excluded; however, in solution; this calcium complex slowly degrades.
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University , Humboldtstrasse 8, D-07743 Jena, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Müller
authors.forename: Sven
authors.initials: S
authors.lastname: Krieck
authors.forename: Helmar
authors.initials: H
authors.lastname: Görls
authors.forename: Matthias
authors.initials: M
authors.lastname: Westerhausen