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Z. Naturforsch. 2012,
67b, 519 – 531
doi:10.5560/ZNB.2012-0085
3-Phenyl-5-(2-pyridyl)pyrazolato Complexes of Lithium, Magnesium, Calcium, and Zinc
Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstrasse 8, D-07743 Jena, Germany
Reprint requests to Prof. M. Westerhausen. E-mail:
m.we@uni-jena.de
Received March 26, 2012 / published online July 6, 2012
Dedicated to Professor Wolfgang Beck on the occasion of his 80th birthday
Metalation of 3-phenyl-5-(2-pyridyl)pyrazole (HPz, 1) with alkyllithium and -zinc compounds in tetrahydrofuran (thf) yields dinuclear products [(thf)Li(Pz)]2 (2) and [MeZn(Pz)]2 (3), respectively. Magnesiation of 1 with diethylmagnesium in tetrahydrofuran in the presence of 1,4-dioxane leads to cocrystallization of mononuclear [(thf)2Mg(Pz)2] (4a) and [(diox)2Mg(Pz)2] (4b). Metalation of 1 with KH followed by a metathesis reaction with CaI2 in tetrahydrofuran leads to the formation of dinuclear [{(thf)2Ca}(μ-Pz)3Ca(Pz)] (5) with the calcium atoms in different coordination environments. The ligand precursor 1 crystallizes as a dimer with
N–H···N bridges between the pyrazole fragments. The pyrazolate anions of the metal complexes 2 to 5 exhibit similar structural parameters regardless of a bridging or terminal coordination mode and the electronegativity of the coordinated metal.
Key words: Calcium, Lithium, Magnesium, Metalation Reactions, Pyrazolates, Zinc