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.