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. (15th October 2016)

• Record Type: Journal Article
• Authors: Váhovská, Lucia; Potočňák, Ivan; Vitushkina, Svitlana; Walko, Martin
• Is Part Of: Polyhedron. Volume 117(2016)
• Page Start: 359
• Page End: 366
• Publication Date: 2016-10-15
• Subjects: Cobalt -- Dicyanamide -- Dicyanoguanidine -- Tricyanomethanide -- CO2 uptake; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2016.06.007
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: [Co II ( bpy )2 (dca)2 ] (1 ) and [Co II ( bpy )2 (tcm)2 ] (2 ) complexes ( bpy = 2, 2-bipyridine, dca = dicyanamide and tcm = tricyanomethanide) were prepared as powders. During their recrystallization on air, CO2 uptake was observed resulting in a formation of two new carbonato complexes, [Co III ( bpy )2 CO3 ]dcg (dcg = N, N′-dicyanoguanidine) (3 ) and [Co III ( bpy )2 CO3 ]tcm·2H2 O (4 ). 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 CO3 ]dcg (dcg = N, N′-dicyanoguanidine, (H2 N)C(NCN)2 ) (3 ) and [Co III ( bpy )2 CO3 ]tcm·2H2 O (4 ), have been prepared. Composition of both complexes was supported by the results of thermal analyses. The presence of Co(III) atom in3 and4 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 in3 is present in its anionic form. Single crystal X-ray structure determination of3 and4 revealed the presence of [Co III ( bpy )2 CO3 ] + 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–H⋯N, O–H⋯N, as well as weak C–H⋯N, C–H⋯O hydrogen bonds and aromatic π–π stacking besides electrostatic forces of attraction help to consolidate the packing.