Synthesis and characterization of inner-sphere substitution products in azide-containing сobalt(III) dioximates

Abstract

New compounds of Co(III) dimethylglyoximate with the sulfanilamide derivative [Co(N3)(DmgH)2(SAM)] (DmgH– is the dimethylglyoxime monoanion, and SAM is–NH2–C6H4–SO2–NH–R) are synthesized using the structural block [Co(N3)(DmgH)2(Н2О)] as the initial one. The reaction products of various [Co(N3)(DmgH)2(SAM)] with ligand L (L is pyridine (Py), thiourea (Thio), triphenylphosphine (PPh3), nicotinamide (Nia), iso-nicotinamide (INia), isonicotinic acid (НINА), 4-pyridinaldoxime (4-PaoH), 4,4’-bipyridine (Bipy), and NH4NCS) are synthesized. The compounds are studied by IR and NMR spectroscopy and X-ray diffraction analysis (CIF files CCDC 1414767–1414775 (I, V–XII)). The following facts are established. First, only the coordinated water molecule in [Co(N3)(DmgH)2(Н2О)] is replaced by SAM. Second, SAM from different similar compounds also undergoes substitution by the aforementioned organic ligands. The exception is the compound obtained by the reaction of [Co(N3)(DmgH)2(SAM)] with NH4NCS, due to which the NCS– anion replaces both SAM and inorganic anion N3-. The X-ray diffraction analysis shows that the substitution reactions give both mononuclear compounds [Со(N3)(DmgH)2(Py)], [Со(N3)(DmgH)2(PPh3)], [Со(N3)(DmgH)2(Thio)], [Со(N3)(DmgH)2(Nia)] [Со(N3)(DmgH)2(INia)], [Со(N3)(DmgH)2(HINА)] ∙ H2O, [Со(N3)(DmgH)2(4-PaoH)] ∙ DMF, and [Со(N3)(DmgH)2(Bipy)] and binuclear molecular complexes [(Со(N3)(DmgH)2)2(Bipy)] ∙ 0.5H2O and [(Со(N3)(DmgH)2)2(Bipy)] ∙ H2O, as well as ionic complex (NH4)[Co(SCN)2(DmgH)2] ∙ 3H2O. The obtained compounds supplement a series of complexes that make it possible to evaluate the trans effect of the N3- anion on the bond lengths along the axial coordinate and on the Со–N bonds in the equatorial plane of the octahedron.