Crystal structure of bis(octamethylcyclotetraphosphonitrilium) tetrachlorocobaltate(II), [(NPMe2)4H]2CoCl4
Abstract
Crystals of [(NPMe2)4H+]2CoCl42– are monoclinic, a= 10·435, b= 32·837, c= 11·174Å, β= 102·29°, Z= 4, space group P21/n. The structure was determined with Mo-Kα counter data by Patterson, electron-density, and least-squares methods, to R 0·077 for 1324 observed reflexions. The structure consists of a tetrahedral CoCl42– ion and two protonated eight-membered phosphonitrilic rings, one with a tub and one with a saddle conformation. Each ring contains four distinct pairs of NP bonds: commencing at the protonated nitrogen, 1·70, 1·54, 1·61, and 1·58 Å. These differences, and corresponding valency-angle variations, can be interpreted in terms of π-bonding theories. The CoCl42– ion is tetrahedral with mean Co–Cl 2·29 Å. A feature of the interionic contacts is the presence of two N–H ⋯ Cl hydrogen bonds (each 3·21 Å).