Complexes of 2, 6‐Bis(hydroxymethyl)pyridine with Different Copper(II) Salts Involving the Anions Chloride,Perchlorate, Nitrate and Acetate. Synthesis and Crystal Structures of the Complexes

Complexes of 2, 6‐bis(hydroxymethyl)pyridine (dhmp) with different Cu^II salts [CuCl₂·6H₂O, Cu(ClO₄)₂·6H₂O, Cu(NO₃)₂·3H₂O, Cu(CH₃COO)₂·H₂O] are prepared ( 1 — 5 , respectively), studied by IR, and their crystal structures reported. Dependent on the anion kind, influences on the distortion of the co‐ordination polyhedron, the distribution of donor sites, the formation of a mono‐ or binuclear complex, and the resultant packing structure of the complex are observed, although in no case the counterions of the used Cu^II salts or water of hydration were found in the co‐ordination sphere. Crystal structures of 1 — 5 indicate hexaco‐ordination of the Cu^II ions with N₂O₄‐environment and show that 1 — 4 are mononuclear 2:1 (L:M) complexes, but 5 is a binuclear 4:2 complex. Crystallization of Cu(ClO₄)₂·6H₂O with dhmp yielded two different complexes ( 2 / 3 ). In 3 , one of the dhmp components is mono‐deprotonated and acts as an anionic ligand. The same behavior is found in 5 . Whereas in the neutral ligand complexes 1 , 2 and 4 the basal planes are occupied by O donors, and N atoms are in the axial positions of the octahedrons, in 3 and 5 the bases are formed by two O and two N donor atoms, and O atoms are in the axes. Moreover, complex 3 shows the N atoms in trans position, but 5 in cis position. The packing of the cationic complex units is typical of strong and weak H bond interactions involving the counterions and hydroxylic or aromatic hydrogen atoms to yield complex network structures.     

Structural variation from trinuclears to 1D chains: Syntheses,structures and properties

Five complexes [Co₃(Hpmad)₆]·(4‐sb)₂·(CH₃COO)₂·(H₂O)₂ ( 1 ), [Co₃(Hpmad)₆]·(3‐sb)₂·(CH₃COO)₂·(H₂O)_0.5 ( 2 ), [Co(Hpmad)₂(4‐sb)]_n ( 3 ), [Co(Hpmad)₂(3‐sb)]_n ( 4 ) and {[Co(Hpmad)(SO₄)(H₂O)₂]·H₂O}_n ( 5 ) [Hpmad is 2‐pyrimidineamidoxime, H₂(4‐sb) is 4‐sulfobenzoic acid and H₂(3‐sb) is 3‐sulfobenzoic acid], were prepared at room temperature. Complexes 1 – 5 were characterized by elemental analyses, single crystal X‐ray diffractions, powder X‐ray diffractions, infrared spectra, thermogravimetric analyses, fluorescence spectra and magnetic susceptibility measurements. Complexes 1 and 2 possess the linear trinuclear Co²⁺ structures. Complexes 3 and 4 exhibit similar one‐dimensional (1D) chains. Complex 5 comprises the 1D helical chain. The change of anion in cobalt salt from CH₃COO^? to Cl^? to SO₄^2? leads to the structural evolution from the linear trinuclear Co²⁺ structure to the 1D chain to the 1D helical chain. Complexes 1 – 5 exhibit the Hpmad‐based emissions. The magnetic properties of 1–5 were also investigated.     

Structural,infrared spectral and thermogravimetric analysis of a hydrogen-bonded assembly of cobalt(II) and nickel(II) mixed complex cations with hexamethylenetetraamine and aqua ligands: {[M(hmt)2(H2O)4][M(H2O)6]}(SO4)2·6H2O

The synthesized cobalt(II) and nickel(II) complexes {[M(hmt)₂(H₂O)₄][M(H₂O)₆]}(SO₄)₂·6H₂O [M?=?Co(II) (1) and Ni(II) (2), hmt?=?hexamethylenetetraamine] share the same general formula and chemical name {[bis(hexamethylenetetraamine)tetraaquametal(II)][hexaaquametal(II)]} disulfate hexahydrate. Complexes 1 and 2 have been characterized by elemental analysis, infrared spectroscopy, thermal analysis and magnetic moment determination. Each complex has two different cationic complexes co-crystallizing with the sulfate anions. The crystal structure of 1has been determined. Both complex cations in 1 have distorted octahedral geometry and they are linked to the sulfate anions through the coordinated and lattice water molecules. Each sulfate anion is hydrogen bonded to ten water molecules; two of its oxygen atoms have two hydrogen bonds each while the other two oxygen atoms have three hydrogen bonds each. The three uncoordinated nitrogen atoms of hmt in each [Co(hmt)₂(H₂O)₄]²⁺ cation are hydrogen bonded to water molecules of adjacent [Co(H₂O)₆]²⁺ cations. The thermal decomposition of 1 has been investigated further by analyzing the FTIR spectra of the residues formed from each decomposition step, and the data have contributed to establishing the thermal decomposition pathway of both 1and 2.     

Mixed-ligand cyanide cobalt(III) complexes with 1,2-cyclohexanediaminetetraacetic acid: Synthesis and photochemical properties

[Co(CN)₂(H₃Cdta)] · 2H₂O (I) and Na₂[Co(CN)(Cdta)] · 3H₂O (II) (Cdta⁴⁻ is the 1,2-cyclohexanediaminetetraacetate) were synthesized. In I, the two cyanide ions and the Cdta nitrogen atoms are located in the equatorial plane, the carboxyl groups connected to different N atoms are in axial positions; in addition one of them, like two other uncoordinated carboxyl groups, is protonated. In II, Cdta is a pentadentate ligand coordinated in the cis-equatorial mode. UV excitation of the dicyano complexes at the ligand-to-metal charge transfer band gives organic derivatives of cobalt(III) stable enough for chromatographic isolation. Photolysis of II in neutral medium gives aqua(cyclohexanediaminetriacetato)cobalt (III) complexes as the final products.     

Syntheses and crystal structures of two 2D coordination polymers of cobalt(II) and nickel(II) with the Malonate Dianion Ligand

Two 2D complexes, [Co(mal)(phen)(H₂O)₂] (1) and [Ni(mal)(phen)(H₂O)₂] (2) (mal?=?malonate dianion; phen?=?1,10-phenanthroline), have been synthesized by the reaction of Co(ClO₄)₂·6H₂O and Ni(ClO₄)₂·6H₂O with disodium malonate and 1,10-phenanthroline in MeOH/H₂O solution. Their crystal structures have been determined by X-ray diffraction. The structures of Complexes 1 and 2 show that each metal ion is coordinated by one 1,10-phenanthroline, two water molecules and a malonate ligand forming a distorted octahedral environment and each mononuclear fragment forms a 2D supramolecular network through H-bonding interactions.     

Coordination polymer incorporating cobalt(II) and glycine acid: structure and magnetism

We report the structure and magnetism of a cobalt(II) compound with glycine acid, Co(C₂H₄NO₂)₂ · H₂O (1). It crystallizes in the orthorhombic system, space group P2(1)2(1)2(1) with a = 5.2301(10) Å, b = 10.837(2) Å, c = 13.542(3) Å, R ₁ = 0.0448, wR ₂ = 0.1151. In 1, Co(II) has a slightly distorted square-pyramidal geometry defined by two O atoms and two N atoms from two glycine ligands, and by one O atom from an aqua ligand in the apical position. The molecules form a three-dimensional supramolecular network through O–H ··· O and N–H ··· O hydrogen bonds. Magnetic characterization shows 1 exhibits a negative Curie–Weiss constant and dominant spin-orbit coupling for Co(II).     

New copper(II) complexes including pyridine-2,5-dicarboxylic acid: synthesis,spectroscopic, thermal properties,crystal structure and how these complexes interact with purified PON 1 enzyme

We report the synthesis of two square-pyramidal copper(II) complexes, [Cu(2,5-pydc)(2-aepy)(H₂O)]·H₂O, 1, and [Cu(2,5-pydc)(2-ampy)(H₂O)]·H₂O, 2 (2-aepy = 2-(aminoethyl)pyridine, 2-ampy = 2-(aminomethyl)pyridine, 2,5-pydc = pyridine-2,5-dicarboxylic acid or isocinchomeronic acid). The synthesized complexes have been characterized by X-ray diffraction, FT-IR, elemental, and thermal analysis techniques. The crystal structure of 1 was established by X-ray analysis. Powder X-ray diffraction analysis showed that the complexes are pure. The inhibition of human serum paraoxonase 1 (PON 1, EC 3.1.8.1) enzyme with these complexes were investigated. We used diethyl 4-nitrophenyl phosphate as a substrate to measure the paraoxonase activity of PON 1 enzyme spectrophotometrically. Complexes 1 and 2 decreased the in vitro PON 1 activity with different inhibition mechanisms. Complexes 1 and 2 inhibited paraoxonase activity of this enzyme as competitively and noncompetitively, respectively.     

Syntheses,crystal structures and antibacterial activities of M(II) benzene-1,2,3-triyltris(oxy)triacetic acid complexes

Four metal(II) complexes with benzene-1,2,3-triyltris(oxy)triacetic acid (H₃L), {[Co_1.5(L)(H₂O)₆]·6H₂O}_n (1), {[Co_1.5(L)(4,4′-bipy)_1.5(H₂O)₄]·4H₂O}_n (2), {[Co(HL)(2,2′-bipy)(H₂O)₂]·1.5H₂O}_n (3), and {[Cu(HL)(phen)(H₂O)₂]·H₂O}_n (4) (4,4′-bipy = 4,4′-bipyridine; 2,2′-bipy = 2,2′-bipyridine; phen = phenanthroline), were prepared and structurally characterized. Complex 2 displays a 1-D structure, while 1, 3, and 4 reveal 0-D structures, which further extend to 3-D supramolecular networks by hydrogen bonding interactions, of which 1 and 4 contain double-helical chains, 2 includes meso-helices, and 3 comprises single-helices. Furthermore, the thermal stabilities and antibacterial activities of the complexes were studied.     

Structure of Dibenzocrown Ethers and their H-bonded Adducts. 3. Isolation of Oxonium Ions by Biphenyl-20-crown-6 and [1.5]Dibenzo-18-Crown-6 in Complexes with [NbF6]− and [TaF6]−

The reaction of Nb₂O₅ and Ta₂O₅ with an aqueous solution of hydrofluoric acid, HF in the presence of biphenyl-20-crown-6 (BP20C6, L¹) or [1.5]dibenzo-18-crown-6 ([1.5]DB18C6, L²) results in the complexes [L¹·(H₃O)][NbF₆] (1), [L¹ (H₃O)][TaF₆] (2), [2L²·(H₇O₃)][NbF₆] (3) and [2L²·(H₇O₃)][TaF₆] (4). Complexes 1–4 were identified by the elemental and X-ray structural analysis and IR spectroscopy. Complexes 1 and 2 are isostructural, with the H₃O⁺ oxonium ion embedded in one crown molecule via OH···O hydrogen bonds. Complexes 3 and 4 represent the supramolecular isomers distinctive by the crown conformations and crystal packing, with the (H₇O₃)⁺ cation enclosed in the cage of two crown molecules. Being poor H-bond acceptors, NbF₆⁻ and TaF₆⁻ anions do not compete with the crown oxygen atoms for the oxonium hydrogen atoms, but are involved in the numerous C–H···F short contacts responsible for the extended supramolecular architectures in all cases. A change of crown ethers’ conformation in complexes 1–4 and a correlation between the degree of proton hydration and an accessibility of the crown ether oxygen atoms is observed. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

A Novel Adipate Bridged Supramolecular Layer: Crystal Structure of the Cobalt(II) Complex [(μ‐C6H8O4)4/2Co(μ‐H2O)2Co(H2O)4] · 4 H2O

The pale‐rose compound [(μ‐C₆H₈O₄)_4/2Co(μ‐H₂O)₂Co(H₂O)₄] · 4 H₂O was prepared from adipic acid and CoCO₃ in aqueous solution. The crystal structure (monoclinic, P2₁/n (no. 14), a = 8.061(1), b = 15.160(2), c = 9.708(2) Å, β = 90.939(7)°, Z = 2, R = 0.0405, wR² = 0.0971) consists of adipate bridged supramolecular [(μ‐C₆H₈O₄)_4/2Co(μ‐H₂O)₂Co(H₂O)₄] layers and hydrogen bonded H₂O molecules. The cobalt atoms Co1 and Co2 are distorted octahedrally coordinated by the O atoms of two bridging trans‐H₂O molecules and four bidentate adipate anions (Co1) and by the O atoms of two bridging trans‐H₂O molecules and four monodentate H₂O molecules (Co2), respectively. Equatorial bonds: d(Co1–O) = 2.048 Å (2 × ), 2.060 Å (2 × ); d(Co2–O) = 2.057 Å (2 × ), 2.072 Å (2 × ). Axial bonds: d(Co1–O) = 2.235 Å (2 × ); d(Co2–O) = 2.156 Å (2 × ).     

Five new cobalt(II) complexes based on indazole derivatives: synthesis,DNA binding and molecular docking study

Five cobalt(II) complexes based on 1H-indazole-3-carboxylic acid (H₂L), [Co(phen)(HL)₂]·2H₂O (1), [Co(5,5′-dimethyl-2,2′-bipy)(HL)₂] (2), [Co(2,2′-bipy)₂(HL)₂]·5H₂O (3), [Co₂(2,9-dimethyl-1,10-phen)₂(L)₂] (4) and [Co₂(6,6′-dimethyl-2,2′-bipy)₂(L)₂]·H₂O (5) (2,2'-bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and structurally characterized by elemental analyses, IR and UV-vis spectroscopies and single-crystal X-ray crystallography. The results indicate that 1–3 possess mononuclear Co(II) structures, while 4 and 5 exhibit binuclear structure. 1D water tape which is linked by the multiple hydrogen bonds was embedded in the 3D motif of complex 3. Complexes 4 and 5 show two orthogonal planes of motif that was constituted by phen/2,2′-bipy and indazole acid, respectively. The intermolecular interactions including hydrogen bonding and π-π stacking interactions are stabilizing these complexes. The interactions of the synthesized complexes with calf-thymus DNA (CT-DNA) have been investigated by UV-vis absorption titration, ethidium bromide displacement assay and viscosity measurements. The results reveal that the complexes could interact with CT-DNA via a groove binding mode. Their behavior rationalization was further theoretically studied by molecular docking.     

Synthesis and antimicrobial activities of metal(II) complexes with 2,4-diiodo-6-phenyliminomethyl-phenol

A bidentate ligand, 2,4-diiodo-6-phenyliminomethyl-phenol (HL) has been synthesized from 3,5-diiodosalicylaldehyde and phenylamine in ethanol. Five mononuclear complexes have been synthesized from 2,4-diiodo-6-phenyliminomethyl-phenol reaction with CuCl₂ · 2H₂O, NiCl₂ · 6H₂O, CoCl₂ · 6H₂O, MnCl₂ · 4H₂O, and ZnCl₂ in ethanol or tetrahydrofuran (THF). The complexes were characterized by UV, infrared, ESI-MS, and elemental analyses. Complexes bis(2,4-diiodo-6-phenyliminomethyl-phenol)-copper(II) (1) and bis(2,4-diiodo-6-phenyliminomethyl-phenol)-zinc(II)-THF (5) were characterized by X-ray crystallography. Based on the crystal structure analysis of 1 and 5, coupled to their spectral similarity with other complexes prepared (2, 3, 4), we conclude that 2, 3, and 4 have similar structures to 1. The metal(II) in each complex is four-coordinate by two nitrogens and two oxygens from two ligands. All the complexes were assayed for antibacterial (Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae) activities by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Among the complexes tested, 1 showed the most favorable antimicrobial activity with minimum inhibitory concentrations of 3.125, 6.25, 6.25, 3.125, 3.125, 6.25 µg mL^?1 against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli, and E. cloacae, respectively.     

Syntheses,crystal structures,and magnetic properties of two new manganese(II) complexes based on biphenyl-2,5,2′,5′-tetracarboxylic acid

Two new complexes, [Mn(H₂bptc)(2,2′-bpy)₂]?·?2H₂O (1) and [Mn₃(Hbptc)₂(2,2′-bpy)₃(H₂O)₈]?·?2H₂O (2) (H₄bptc?=?biphenyl-2,5,2′,5′-tetracarboxylic acid, 2,2′-bpy?=?2,2′-bipyridine), have been synthesized under hydrothermal conditions. Their structures have been characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, powder X-ray diffraction, and thermogravimetric analyses. Complexes 1 and 2 are both linked into 3-D supramolecular networks by non-covalent interactions (O–H?···?O, C–H?···?O, C–H?···?π, and π?···?π). Complexes 1 and 2 exhibit weak antiferromagnetic interactions.     

Syntheses,crystal structures and thermodecomposition behaviors of three energetic compounds

Three new energetic compounds, nickel(II) 3,5-dinitro-2-pyridonate (Ni(2DNPO)₂(H₂O)₄, 1), copper(II) 3,5-dinitro-4-pyridonate (Cu(4DNPO)₂(H₂O)₄, 2) and cobalt(II) 3,5-dinitro-4-pyridone-N-hydroxylate ([Co(4DNPOH)₂(H₂O)₄] · 2DMF, 3 · 2DMF), were characterized by elemental analysis, FT–IR, TG-DSC and X-ray single crystal diffraction analysis. Complexes 1 and 2 are similar in structure with the metal ion coordinated by oxygen donors of four water molecules on the equatorial position and two nitrogen donors of the pyridone rings of two ligands in the axial positions. The cobalt(II) complex 3 · 2DMF is a heavily distorted octahedral geometry. The Co(II) has equatorial positions defined by oxygens of four water molecules. Its axial positions are filled with two oxygen atoms of the pyridone-N-hydroxylate of two ligands. The TG-DSC results reveal that 1 is the most stable, with higher initial thermal decomposition temperature and enthalpy. Based on the thermoanalyses, the nickel compound is a promising candidate as a component in catalyzed RDX-CMDB propellants in comparison with our earlier lead(II) analogs.     

Synthesis and antimicrobial activities of metal(II) complexes with bis(2,4-diiodo-6-propyliminomethyl-phenol)-pyridine

Seven new mononuclear complexes have been synthesized from 2,4-diiodo-6-propyliminomethyl-phenol in pyridine and Cu(OAc)₂ · H₂O, Ni(OAc)₂ · 4H₂O, Co(OAc)₂ · 4H₂O, Zn(OAc)₂ · 2H₂O, Cd(OAc)₂ · 2H₂O, Mn(OAc)₂ · 4H₂O, and Hg(OAc)₂. The complexes were characterized by UV, IR, ESI-MS, and elemental analyses; bis(2,4-diiodo-6-propyliminomethyl-phenol)-pyridine-copper(II) (1) was characterized by X-ray crystallography. The central metal in each complex is five-coordinate by two nitrogens and two oxygens from two 3,5-diiodosalicylaldehyde Schiff-base ligands and one nitrogen from pyridine. The 3,5-diiodosalicylaldehyde Schiff base is bidentate. All the complexes were assayed for antibacterial (Bacillus subtilis, Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae) activities by the MTT method. Complex 1 showed the most favorable antimicrobial activity with minimum inhibitory concentrations of 6.25, 3.125, 6.25, 3.125, 6.25, 3.125 µg mL^?1 against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli, and E. cloacae, respectively.     

Darstellung und Struktur der Komplexverbindungen trans‐[CoIII(py)4F2][H2F3] und [Pd(py)4]F2 · 1,5 HF · 2 H2O

Synthesis and Crystal Structures of the Complexes trans ‐[Co^III(py)₄F₂][H₂F₃] and [Pd(py)₄]F₂ · 1.5 HF · 2 H₂O The cobalt complex trans‐[Co(III)(py)₄F₂][H₂F₃] ( 1 ) has been prepared by electrochemical oxidation of CoF₂ in a pyridine/HF mixture and the palladium complex [Pd(py)₄]F₂ · 1.5 HF · 2 H₂O ( 2 ) has been obtained via halogen exchange between Pd(py)₂Cl₂ and AgF₂ in pyridine. 1 and 2 crystallize in the space group C2/c with a = 27.928(14), b = 9.019(3), c = 18.335(8) Å, β = 113.41(3)° for 1 and a = 28.183(9), b = 9.399(3), c = 17.397(6) Å, β = 104.66(3)° for 2 , respectively. Concerning the shape and location of the M(py)₄ fragments 1 and 2 are isostructural. The metal atoms occupy special positions in their unit cells with the result that four complex atoms have C₂ symmetry and four complex cations have C_i symmetry giving a total of Z = 8. In 1 two F^– ions complete an octahedral coordination around the Co atoms (Co–F 1.820(2) to 1.834(3) Å). In 2 the shortest Pd–F distance is 3.031(2) Å. This precludes the existence of Pd–F bonds. In 1 one can identify H₂F₃^– groups. In 2 there are larger aggregates, consisting of F^–, HF, and H₂O subunits, connected by H‐bridges. In spite of these differences, both complexes belong to the same type of structure, which may be of a common type M^x+(py)₄F_x · y HF · z H₂O.     

Synthesis and antibacterial activities of metal(II) complexes with Schiff bases derived from 3,5-diiodosalicylaldehyde

Two new Schiff bases (2,4-diiodo-6-[(2-morpholin-4-yl-ethylimino)-methyl]-phenol and 2,4-diiodo-6-[(3-morpholin-4-yl-propylimino)-methyl]-phenol), condensed from 3,5-diiodosalicylaldehyde with 2-morpholinoethylamine and 3-morpholinopropylamine, have been designed and synthesized. Reaction of the Schiff bases with Zn(OAc)₂ · 2H₂O, Cu(OAc)₂ · H₂O, Ni(OAc)₂ · 4H₂O, Co(OAc)₂ · 4H₂O, Cd(OAc)₂ · 2H₂O, Mn(OAc)₂ · 4H₂O, Fe(SO4)₂ · 7H₂O, and Hg(OAc)₂ led to the formation of 16 new mononuclear complexes. The complexes were characterized by UV, Infrared, ESI-MS, and elemental analyses, and 3,5-diiodosalicylalidene-2-morpholinoethylaminozinc(II) (1) and 3,5-diiodosalicylalidene-2-morpholinoethylaminocopper(II) (2) were characterized by single crystal X-ray diffraction. Based on crystal structural analysis of 1 and 2, coupled with their spectral similarity with 3–16, it can be concluded that 3–16 have structures similar to 1 and 2. All the complexes were assayed for antibacterial activities against three Gram positive bacterial strains (Bacillus subtilis, Staphylococcus aureus, and Streptococcus faecalis) and three Gram negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter cloacae) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. Among the complexes tested, 8 and 16 showed the most favorable antibacterial activity with minimum inhibitory concentration of 0.781, 12.5, 6.25, 3.125, 3.125, 6.25 and 1.562, 6.25, 1.562, 3.125, 3.125, 1.562 µg mL^?1 against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli, and E. cloacae, respectively.     

Synthesis,crystal structure and luminescence of a 3-D coordination polymer based on 4-(1H-tetrazol-5-yl) benzoic acid

A cobalt(II) coordination polymer [Co(4-TZBA^2?)(H₂O)₂] (1) was obtained by treatment of Co(ClO₄)₂ · 6H₂O with 4-(1H-tetrazol-5-yl)benzoic acid [H₂(4-TZBA)] under hydrothermal conditions. The X-ray single crystal diffraction analysis reveals that 1 crystallizes in monoclinic P2₁/c, with a = 10.503(2) Å, b = 9.0860(18) Å, c = 10.179(2) Å, β = 96.75(3)° and Z = 4. In 1, adjacent cobalt(II) atoms are bridged by two 4-TZBA^2? ligands to form a dimer, which is linked with six dimers to result in a 3-D structure. 1 exhibits strong luminescence at room temperature in the solid state.     

Synthesis and Structural Features of New Schiff Base Complexes of Mononuclear MnIV,Dinuclear CoIICoIII,and Tetranuclear CuII

2‐(((2‐Hydroxy‐3‐methoxyphenyl)methylene)amino)‐2(hydroxymethyl)‐1,3‐propanediol (LH₄, as abbreviation) reacts with MnCl₂ · 4H₂O, CoCl₂ · 6H₂O, and Cu(ClO₄)₂ · 6H₂O to give the new complexes [Mn(LH₂)₂] ( 1 ), [Co₂Cl(H₂O)(LH₂)₂] · 4H₂O ( 2 ), and [Cu₄(LH₂)₄(H₂O)₄] ( 3 ). Complex 1 is formed by the assembly of two molecules of the ligand with one manganese(IV) ion. In the mixed‐valence cobalt complex 2 there is an asymmetry between the coordination spheres of cobalt(II) and cobalt(III). In the tetramer 3 four copper(II) ions attain a distorted tetrahedral configuration surrounded by four molecules of the ligand.     

Mononuclear Co(III), Ni(II) and Cu(II) complexes of 2‐(2,4‐dichlorobenzamido)‐N'‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide: Structural insight and biological assay

A series of mononuclear metal complexes of Co(III), Ni(II) and Cu(II) with 2‐(2,4‐dichlorobenzamido)‐N′‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide ( LH ₃ ) have been synthesized and characterized using various physico‐chemical, spectroscopic and single crystal X‐ray diffraction techniques. Structural studies of [Co( LH )( LH ₂ )]·H₂O ( 4 ) revealed the presence of both amido and imidol tautomeric forms of LH ₃ , resulting in a distorted octahedral geometry around the Co(III) ion. [Ni( LH )(H₂O)]·H₂O ( 5 ) and [Cu( LH )(H₂O)]·H₂O ( 6 ) are isomorphous structures and crystallize in the monoclinic P2₁/c space group. The crystal structures of 4 , 5 and 6 are stabilized by hydrogen bonds formed by the enclathrated water molecules, C‐H···π and π···π interactions. Complexes along with the ligand ( LH ₃ ) were screened for their in vivo anti‐inflammatory activity (carrageenan‐induced rat paw edema method) and in vitro antioxidant activity (DPPH free radical scavenging assay). Metal complexes have shown significant anti‐inflammatory and antioxidant potential.