Abstract
•Two high-spin Co(III) complexes have been achieved through careful metathesis reactions.•The size of the counter cations has a major impact on the crystal structures.•Experimental PXRD patterns are in agreement with simulations, thus confirming the phase purity.•Structural cohesion is established essentially by hydrogen bonding and π–π stacking interactions.•The two salts exhibit weak antiferromagnetic interactions at low temperatures.
Two novel hybrid salts containing high spin tris(oxalato)cobaltate(III) complexes and pyridinium derivative isomer cations, viz. (C7H11N2)3[Co(C2O4)3]·nH2O (C7H11N2+ = 2-amino-4,6-dimethylpyridinium cation, n = 0 for salt 1; C7H11N2+ = 4-dimethylaminopyridinium, n = 4 for salt 2) were successfully isolated from aqueous solution. They were characterized using various physicochemical techniques, such as C, H, N microanalyses, thermogravimetric studies, FT-IR, UV-Vis, EDX, PXRD, single-crystal X-ray crystallography, and SQUID magnetometry. The size of the pyridinium derivative isomer cations has a major impact on the crystal structures. Salt 1 has a 3-D supramolecular framework formed by O–H∙∙∙O hydrogen bonds between the high-spin [Co(C2O4)3]3− complex anion and the sterically encumbering 2-amino-4,6-dimethylpyridinium cations. The 3-D supramolecular framework of salt 2 is comprised of [Co(C2O4)3]3− complex anion, small size 4-dimethylaminopyridinium cations and uncoordinated water molecules via N–H∙∙∙O and O–H∙∙∙O hydrogen bonds. Structural cohesion is reinforced by π–π stacking interactions between the pyridine rings in both salts. Temperature-dependence magnetic moment (µ) collected under zero-field cooled (ZFC) and field-cooled (FC) conditions revealed robust antiferromagnetic ordering below TN = 25 K. The negative Weiss constant, θ = −55 K, confirmed the presence of antiferromagnetic interactions between Co(III) ions at low temperatures in 1 and the estimated effective magnetic moment of 4.5 μB supports the presence of the rare Oh high-spin Co(III) in this hybrid salt.
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Two high-spin Co(III) complexes have been isolated and their magnetic behavior evaluated.