title: Unexpected formation and crystal structure of tetra-kis-(1H-pyrazole-κN (2))-palladium(II) dichloride.
abstract: The title salt, [Pd(C3H4N2)4]Cl2, was obtained unexpectedly by the reaction of palladium(II) dichloride with equimolar amounts of 1-chloro-1-nitro-2,2,2-tris-(pyrazol-yl)ethane in methanol solution. The Pd(2+) cation is located on an inversion centre and has a square-planar coordination sphere defined by four N atoms of four neutral pyrazole ligands. The average Pd-N distance is 2.000 (2) Å. The two chloride anions are not coordinating to Pd(2+). They are connected to the complex cations through N-H⋯Cl hydrogen bonds. In addition, C-H⋯Cl hydrogen bonds are observed, leading to a three-dimensional linkage of cations and anions.
authors.affiliation: Chemisches Institut, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wagner
authors.affiliation: Institut für Organische Chemie, Technische Universität Clausthal, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany.
authors.forename: Nena
authors.initials: N
authors.lastname: Christiansen
authors.affiliation: Chemisches Institut, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg, Germany.
authors.forename: Cristian G
authors.initials: CG
authors.lastname: Hrib
authors.affiliation: Institut für Organische Chemie, Technische Universität Clausthal, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, Germany.
authors.forename: Dieter E
authors.initials: DE
authors.lastname: Kaufmann
authors.affiliation: Chemisches Institut, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg, Germany.
authors.forename: Frank T
authors.initials: FT
authors.lastname: Edelmann
keywords: crystal structure; homoleptic metal–pyrazole complex; hydrogen bonding; palladium(II); solvolytic ligand degradation