Synthesis and Crystal Structure of [Co(DmgH)2(Thio)2]2F[PF6]. The Effect of Fluorine-Containing Co(III) Dioximates on the Physiological Processes of the Microalga Porphyridium cruentum

Russian Journal of Coordination Chemistry - New fluorine-containing cobalt(III) dioximates [Co(DmgH)2(Thio)2]2F[PF6] (I) and [Co(DmgH)2(Sam)2]2[TiF6] · 4H2O (II) (DmgH = dimethylglyoxime...     

Asymmetric and symmetric cobalt(III) dioximates with pyrazinecarboxamide: Synthesis and crystal structure

A number of novel complexes of cobalt(III) trans-dioximates containing pyrazinecarboxamide were obtained: [CoBr(DfgH)₂(Pzca)] · 0.125H₂O (I), [CoCl(NioxH)₂(Pzca)] (II), [CoCl(DmgH)(NioxH)(Pzca)] · 0.5C₂H₅OH · 0.5H₂O (III), and [CoCl(DmgH)₂(Pzca)] (IV), where DmgH, DfgH, and NioxH are the monoanions of dimethylglyoxime, diphenylglyoxime, and cyclohexane-1,2-dione dioxime, respectively; Pzca is pyrazinecarboxamide. Complexes I?CIII were examined by X-ray diffraction. In these complexes, the Co(III) atom has an octahedral environment with the pseudomacrocyclic fragment (DioxH)₂ in the equatorial plane (DioxH is the ??-dioxime residue). The latter is stabilized by hydrogen bonds O-H?O. In all the complexes, the organic ligand is monodentate and coordinated through one N atom of the heterocycle so that it is trans to the halide anion.     

Synthesis and structure of cobalt(III) dimethylglyoximate with [FeF<Subscript>5</Subscript>(H<Subscript>2</Subscript>O)]<Superscript>2−</Superscript> anion

A new complex [Co(DH)₂(Thio)₂]₂[FeF₅(H₂O)] · 2CH₃OH (where DH^? is dimethylglyoxime monoanion, Thio is thiourea molecule) was synthesized and its structure was determined. The coordination polyhedron of the Co(III) atoms in two centrosymmetric complex cations is an octahedron, formed by four N atoms of two dimethylglyoxime residues and two S atoms of coordinated Thio molecules. One of the Thio molecules is almost perpendicular to a metal cycle (the dihedral angle 87.8(1)°), which is responsible for realization of intermolecular hydrogen bond N-H···O (N···O 2.990(3) Å). The second Thio molecule is almost parallel to the equatorial CoN₄ fragment (the dihedral angle 159.4(1)°) to give rise to intramolecular π-π interaction between practically planar Thio molecule and one of the π-delocalized metal cycle. The Fe(III) coordination polyhedron is an octahedron, formed by five F atoms and by the O atom of coordinated water molecule. The key role in the crystal structure organization is played by intermolecular hydrogen bonds N-H···F, N-H···O, N-H···S, the intramolecular bonds O-H···O, formed by the donor NH₂ groups of a complex cation with the F atoms of the [FeF₅(H₂O)]^2? and the donor-acceptor groups of the Thio fragments.     

Synthesis and crystal structure of cobalt(III) α-dioximates with pyrazine

A series of new coordination compounds of cobalt(III) trans-dioximates with pyrazine [CoCl(DH)₂Pz] · H₂O (I), [CoBr(DH)₂Pz] · H₂O (II), [Co(DH)₂Pz₂]NO₃ · H₂O (III), [Co(DH)₂Pz₂][BF₄] (IV), [Co(MgH)₂Pz₂][BF₄] (V), and [Co(NioxH)₂Pz₂][BF₄] (VI), where DH, MgH, and NioxH are dimethylglyoxime, methylglyoxime, and 1,2-cyclohexanedionedioxime monoanions, respectively, Pz is a pyrazine molecule were synthesized. The structures of compounds I, II, and VI were determined by X-ray diffraction. The Co(III) environment in these compounds is octahedral and the pseudomacrocyclic (DioxH⁻)₂ fragment occurs in the equatorial plane. This fragment is stabilized by O-H…O hydrogen bonds. The neutral Pz ligand is monodentate in all three compounds.     

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

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%.     

Synthesis,crystal structure,and biological properties of the complex [Co(DmgH)<Subscript>2</Subscript>(Seu)<Subscript>1.4</Subscript>(Se-Seu)<Subscript>0.5</Subscript>(Se<Subscript>2</Subscript>)<Subscript>0.1</Subscript>][BF<Subscript>4</Subscript>]

A new Co(III) dioxime complex with selenocarbamide was obtained by the reaction of Co(BF₄)₂ ? 6H₂O, DmgH₂, and Seu (DmgH2 = dimethylglyoxime, Seu = selenocarbamide). According to X-ray diffraction (CIF file CCDC no. 1485732), the product was an ionic coordination compound with unusual composition, [Co(DmgH)₂(Seu)_1.4(Se-Seu)_0.5(Se₂)_0.1][BF₄] (I). Apart from two monodeprotonated DmgH￣ molecules, the central atom coordinates neutral Seu, Se-Seu, and Se₂ molecules. Thus, the crystal contains the complex cations [Co(DmgH)₂(Seu)₂]⁺, [Co(DmgH)₂(Seu)(Se-Seu)]⁺, and [Co(DmgH)₂(Seu)(Se₂)]⁺. Each [BF₄]￣ anion is linked to the cations not only by electrostatic forces but also by intermolecular N–H···F hydrogen bonds (H-bonds). The complex cations are combined by intermolecular N–H···O H-bonds. The new coordination compound was found to possess biological activity. Treatment of the garlic (Allium sativum L.) foliage with an aqueous solution of I optimizes the content of selenium in the leaves and cloves and enhances the growth and plant productivity. The organs of treated plants are characterized by enhanced antioxidant protection owing to increasing activity of antioxidant enzymes and contents of proline and assimilation pigments, and decreasing lipid peroxidation.     

Cobalt(III) dimethylglyoximates containing selenourea and an unusual diselenourea ligand: Synthesis and structures

The complexes [Co(DH)₂(Seu) _y (Se-Seu) _z ]₂X · mSolv (DH is the dimethylglyoxime monoanion, Seu is selenourea, and X is [TiF₆]²⁻, [ZrF₆]²⁻) were obtained from the system CoX · 6H₂O-DH₂-Seu in DMF-MeOH or MeOH-H₂O and examined by UV, IR, and NMR spectroscopy and X-ray diffraction. Unexpectedly, the ligand Se-Seu (the oxidized form of selenourea) was detected on the axial coordinate, partially replacing selenourea. The complexes were formulated as [Co(DH)₂(Seu)_1.75(Se-Seu)_0.25]₂[TiF₆] · H₂O (I) and [Co(DH)₂(Seu)(Se-Seu)]₂[ZrF₆] · 3H₂O (II). The complex cations in I and II have trans-octahedral structures. Their crystal structures are made up of the complex Co³⁺ cations and the outer-sphere MF₆²⁻ anions (M = Ti(IV) (I) and Zr(IV) (II)) held together by electrostatic interactions and hydrogen bonds; water of crystallization is also involved in hydrogen bonding.     

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.     

Dianilineglyoxime Salt and Its Binuclear Zn(II) and Mn(II) Complexes with 1,3-Benzenedicarboxylic Acid: Synthesis and Structures

Russian Journal of Coordination Chemistry - Single crystals of dianilineglyoxime (DAnH2) in the form of hydrate salts [DAnH3](ClO4) ? H2O (I) and [DAnH3](ClO4) ? 1.25H2O (II) are...     

Iron(II) Bis-α-Benzyldioximate Complexes with 3- and 4-Pyridine Hemiacetals as Axial Ligands: Synthesis,Structure, and Physicochemical Properties

Russian Journal of Coordination Chemistry - The coordination compounds [Fe(DfgH)2(HL1)2] and [Fe(DfgH)2(HL2)2], where DfgH = is the α-benzyldioxime monoanion, HL1 = 3-pyridine hemiacetals:...