Synthesis and Structure of Co(III) Coordination Compounds [Co(DH)2(Anil)2][BF4] and [Co(DH)2(Py)2][BF4]

The complex compounds [Co(DH)₂(Anil)₂][BF₄] and [Co(DH)₂(Py)₂][BF₄] were synthesized from Co(BF₄)₂ · 6H₂O–DH₂–A–alcohol–water systems (DH₂ is dimethylglyoxim and A is pyridine (Py) or aniline (Anil)), and their crystal structures were determined using X-ray diffraction analysis. In octahedral Co(III) complexes, two dimethylglyoxime radicals lie in the equatorial plane and are joined via the intramolecular hydrogen bond O–H···O. The complexes with pyridine and aniline have similar configurations but different crystal structures.     

Synthesis,Crystal and Molecular Structures of [Co(MH)2(Thio)2][BF4] · H2O and [Co(DH)2(NH3)2][BF4]

Crystal structures of [Co(MH)₂(Thio)₂][BF₄] · H₂O (I) and [Co(DH)₂(NH₃)₂][BF₄] (II), where MH^– is H₃C–C(NOH)–C(NO^–)–H and DH^– is H₃C–C(NOH)–C(NO^–)–CH₃, were determined by X-ray diffraction. The crystals are monoclinic, space group C2/c, unit cell parameters (for I and II, respectively): a = 22.018(2) Å, b = 7.943(1) Å, c = 11.681(1) Å, = 92.68(1)° and a = 21.436(2) Å, b = 6.400(2) Å, c = 12.389(2) Å, = 113.13(1)°. In both cases, the Co(III) coordination polyhedron is a centrosymmetrical trans-octahedron, N₄S₂ for I and N₆ for II. In the crystals of I and II, the complex cations and the outer-sphere [BF₄]^– anions (and the crystal water molecules in I) form elaborate hydrogen bonding system.     

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

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 N ₃ ^- . 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 N ₃ ^- anion on the bond lengths along the axial coordinate and on the Со–N bonds in the equatorial plane of the octahedron.     

Structure of the [Co(NioxH)2(PPh 3)2]F complex

Compound [Co(NioxH)₂(PPh ₃)₂]F is synthesized in the CoF₂ · 4H₂O-NioxH₂-PPh ₃ system (where NioxH is the 1,2-cyclohexanedione dioxime monoanion and PPh ₃ is triphenylphosphine), and its structure is determined by X-ray diffraction. It is shown that the cobalt atom has the octahedral environment. Two nioxime residues that are related by the center of symmetry lie in the equatorial plane and are linked by the O-H?O hydrogen bond. The 1,6-positions of the octahedron are occupied by the phosphorus atoms of the triphenylphosphine ligands. The formation of the crystal structure of this compound is discussed.