Synthesis, structure, and biological properties of mixed cobalt(III) dioximates with guanidine derivatives

详细

Two Co(III) dioximates, cyanoguanidine complex {[Na₂(µ-H₂O)₂(L¹)₂(H₂O)₂]-[Co^III(DmgH)₂(N₃)₂]}_n[Co^III(DmgH)₂(N₃)₂]_n (L¹ = (H₂N)₂C=N–C=N) (I) and aminoguanidine complex [H₃L²][Co(DmgH)₂(N₃)₂] (H₂L² = H₂N–C(=NH)–NH–NH₂) (II), were synthesized from the [CoCl(DmgH)₂(H₂O)] structural unit (DmgH^– is the dimethylglyoxime monoanion). The implementation of the synthesis was confirmed by chemical analysis, IR spectroscopy, and X-ray diffraction (CIF files CCDC 1531845 (I), 1531846 (II)). Both compounds are ionic. Compound I consists of cations representing centrosymmetrical 2D coordination polymers, {[Na₂(µ-H₂O)₂(L¹)₂(H₂O)₂][Co^III(DmgH)₂(N₃)₂]}ⁿ⁺_n, and monomeric [Co(DmgH)₂(N₃)₂]^– anions, while in II, the charge of the [Co(DmgH)₂(N₃)₂]^– complex anion is counterbalanced by the organic [H₃L²]⁺ cation. In I, L¹ is coordinated to the metal as a monodentate neutral ligand, while in II, H₂L² occurs in the complex as a protonated uncoordinated component. Since L¹ in I and H₂L² in II contain functional amine groups able to form intermolecular hydrogen bonds acting as proton donors, the component packing mode in the crystals was analyzed assuming various types of interactions, apart from electrostatic ones. The biological properties of the complexes were tested considering their effect on the biosynthesis of proteases by the micromycete Fusarium gibbosum CNMN FD 12 strain. Culturing the producer on a culture medium containing complex I in the selected optimal concentrations of 5–10 mg/L was found to increase the acid protease activity by 140–150%.