Low dimensional compounds containing cyanido groups. Part XXX. Recrystallization of Co(II) complexes with pseudohalogenide ligands leading to CO2 uptake and formation of dicyanoguanidine anion in newly created Co(III) complexes
Abstract Two new complexes, [Co II bpy 2 (dca) 2 1 and [Co II bpy 2 (tcm) 2 2 bpy 2,2 bipyridine, dca dicyanamide and tcm tricyanomethanide) were prepared as powders. During their recrystallization on air, two other new complexes, [Co III bpy 2 CO 3 ]dcg (dcg N,N' dicyanoguanidine, (H 2 N)C(NCN) 2 3 and [Co III bpy 2 CO 3 ]tcm*2H 2 O 4 have been prepared. Composition of both complexes was supported by the results of thermal analyses. The presence of Co(III) atom in 3 and 4 was confirmed by UV Vis spectra, while the presence of dcg and tcm as free anions was proved by IR spectra of these complexes. Moreover, quantum chemical calculations confirmed that dcg in 3 is present in its anionic form. Single crystal X ray structure determination of 3 and 4 revealed the presence of [Co III bpy 2 CO 3 complex cations with dcg, its structure has not been published yet, and tcm counter anions, respectively. In both structures, a supramolecular networks built up from strong N HN, O HN, as well as weak C HN, C HO hydrogen bonds and aromatic p p stacking besides electrostatic forces of attraction help to consolidate the packing.