Collect. Czech. Chem. Commun. 1993, 58, 845-853

Nucleophilic Addition in Transition Metal, Pseudohalide-4-nitropyrazole Systems

Mária Hvastijováa, Jiří Kohouta and Renate Skirlb

a Department of Inorganic Chemistry, Slovak Technical University, 812 37 Bratislava, Slovak Republic
b Fachbereich Chemie, Martin-Luther-University, Halle-Wittenberg, 4059 Halle/Saale, Germany


The possibility of nucleophilic addition of 4-nitropyrazole (4-NO2-pz) to a pseudohalide group present in the coordination sphere of a central atom was investigated. Ten products were isolated from M(II)-X--4-nitropyrazole systems with M = Cu, Ni or Co and X = NCO, N(CN)2 or C(CN)3, and investigated by infrared and electronic spectroscopy. Four of these compounds were pseudohalide complexes, two were complexes with anionic chelate ligands formed by nucleophilic addition, and the remaining products were mixtures of pseudohalide and chelate complexes. The [Cu(NCO)2(4-NO2-pz)2] complex is rhombic octahedral or five-coordinate, the [Cu(NCO)2(4-NO2-pz)] complex is five-coordinate. The remaining compounds possess octahedral or pseudooctahedral structures which involve pseudohalide bridging in the [MX2(4-NO2-pz)2] type complexes, or bridging via free carbamoyl oxygens or cyanide nitrogens in the [M(4-NO2-pz.X)2] type complexes.