Concept for Enhancement of the Stability of Calcium-Bound Pyrazolyl-Substituted Methanides

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(Pzth)2Ph}­{N­(SiMe3)2}] (3). The α,α-bis­(3-thiophen-2-ylpyrazol-1-yl)­benzyl ligand exhibits a κ2N,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.