Synthesis and characterization of novel (<Emphasis Type="Italic">E</Emphasis>,<Emphasis Type="Italic">E</Emphasis>)-dioxime and its mono- and polynuclear metal complexes containing azacrown moieties

The novel (E,E)-dioxime,7,8-bis(hydroxyimino)-1,14-bis(monoaza[8]crown-6)-benzo[f]-4,11-dioxa-1,14-diazadecane[7,8-g]quinoxaline (H₂L), has been synthesized by the reaction of 6,7-diamino-1,12-bis(monoaza[18]crown-6)benzo[f]-4,9-dioxa-1,12-diazadecane (4) which has been prepared by the reduction of 6,7-dinitro-1,12-bis(mono-aza[18]crown-6)benzo[f]-4,9-dioxa-1,12-diazdecane (3) and cyanogendi-N-oxide. Mononuclear Ni^II and Cu^II complexes of H₂L have a metal:ligand ratio of 1:2 and the ligand coordinates through two hydroxyimino nitrogen atoms, as do most of the (E,E)-dioximes. The hydrogen-bridged Ni^II complex was converted into its BF ₂ ⁺ capped anologue by the reaction with BF₃ · Et₂O. The reaction of the Cu^II complex with 2,2′-dipyridyl as an end-cap ligand gave the homotrinuclear complex. Structures for the ligand and its complexes are proposed in accordance with elemental analysis, magnetic susceptibility measurements, ¹H, ¹³C-n.m.r, IR and MS spectral data.     

Synthesis and spectral characterization of macrocyclic Schiff base by reaction of 2,6-diaminopyridine and 1,4- bis (2-carboxyaldehydephenoxy)butane and its CuII, NiII, PbII, CoIII and LaIII complexes

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:15,16-tribenzo-9,15-dioxacycloheptadeca-1,5-diene (L) was synthesized by reaction of 2,6-diaminopyridine with 1,4-bis(2-carboxyaldehydephenoxy)butane. Then, its Cu^II, Ni^II, Pb^II, Co^III and La^III complexes were synthesized by the template effect by reaction of 2,6-diaminopyridine and 1,4-bis (2-carboxyaldehydephenoxy)butane and Cu(NO₃)₂ · 3H₂O, Ni(NO₃)₂ · 6H₂O, Pb(NO₃)₂, Co(NO₃)₂ · 6H₂O, La (NO₃)₃ · 6H₂O, respectively. The ligand and its metal complexes were characterized by elemental analysis, IR, ¹H- and ¹³C-n.m.r., UV-vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements and mass spectra. All complexes are diamagnetic and the Cu^II complex is binuclear. The Co^II complex was oxidised to Co^III.     

Synthesis and Characterization of Two vic-Dioximes Containing the 1,3-Dioxolane Ring and 1,4-Diaminobutane and Their Cobalt(II), Nickel(II), Copper(II) and Zinc(II) Metal Complexes

Two new vic-dioxime ligands, (E,E)-N-{4-[(1,4-dioxaspiro[4.4]non-2-ylmethyl)amino]butyl}-N-hydroxy-2-(hydroxyimino)ethanimidamide (L¹H₂) and (E,E)-N-{4-[(1,4-dioxaspiro[4.5]dec-2-ylmethyl)amino]butyl}-N-hydroxy-2-(hydroxyimino)ethanimidamide (L²H₂) containing two different heteroatoms (N,O) have been prepared from anti-chloroglyoxime, N-(1,4-dioxaspiro[4.4]non-2-ylmethyl)butane-1,4-diamine (3) and N-(1,4-dioxaspiro[4.5]dec-2-ylmethyl)butane-1,4-diamine (4). Co^II, Ni^II and Cu^II complexes of the ligands have a metal:ligand ratio of 1:2 and the ligands coordinate through the two N atoms, as do most of the vic-dioximes. However, Zn^II complexes of the ligands have a metal:ligand ratio of 1:1 and the ligands are coordinated only by the N, O atoms of the vic-dioximes. In the Co^II complexes two water molecules, and in the Zn^II complexes a chloride ion and a water molecule, are also coordinated to the metal ion. The structures of the compounds were determined by a combination of elemental analysis, magnetic moments, molar conductances, thermogravimetric analysis (t.g.a.) and spectroscopic (u.v.–vis., i.r., ¹H- and ¹³C-n.m.r.) data.     

Coordinating properties of C2-symmetric chiral bis(oxazolinylpyridinyl)dioxolane ligands

Metal complexes of general formula M(L)X₂ and M(L)X₃ [L = (4S,5S)-2,2-dimethyl-4,5-bis{6-[(4,5-dihydro-4-(S)-(1-methylethyl)oxazol-2-yl)pyridin-2-yl]}-1,3-dioxolane] were obtained by reacting, respectively, Co^II, Cu^II, Ni^II, and Zn^II nitrate salts and the Rh^III chloride salt, with a chiral C₂-symmetric bis(oxazolinylpyridinyl)dioxolane (L) ligand, in MeOH/CHCl₃ solution. A single crystal X-ray analysis was carried out on [Ni(L)(OH₂)₂](NO₃)₂ · 2H₂O and the molecular structure of L was also determined. In the free ligand the two symmetric arms are essentially planar and oriented nearly perpendicular to the dioxolane average plane. In the Ni complex one seven-membered and two five-membered chelation rings are formed. The metal atom also lies on the C₂ axis, and two symmetry-related water molecules complete the octahedral coordination environment. Both compounds crystallize in chiral space groups; the ligand crystallizes in orthorhombic system, space group C 2 2 2₁, Z = 4; the nickel complex crystallizes in tetragonal system, space group P 4₃ 2₁ 2, Z = 4.     

Cobalt(II) Complexes with Dicyanamide — from Binuclear Entities to Chains

One binuclear complex [Co(bpm*)₂(dca)]₂(ClO₄)₂ ( 1 ) and two 1D chain Co^II complexes, {[Co(bpm)₂(dca)](ClO₄)}_n ( 2 ) and [Co(dmf)₂(dca)₂]_n ( 3 ), (bpm*: bis[(3, 5‐dimethyl)pyrazolyl]methane; bpm: bis(pyrazolyl)methane; dca: dicyanamide; dmf: N, N‐dimethyl formamide) have been prepared and structurally characterized. The cobalt atoms are hexa‐coordinated forming a slightly distorted octahedral coordination. Compound 1 crystallizes in the monoclinic system, space group P2₁/c, a = 9.849(3)Å, b = 21.944(7)Å, c = 13.814(5)Å, β = 94.824(6), Z = 4, R₁ = 0.0672, wR₂ = 0.1395. 1 is a binuclear complex linked by two dca ligands, and each Co^II ion is coordinated by two terminal bpm* ligands. Compound 2 crystallizes in the orthorhombic system, space group Cmcm, a = 10.377(4)Å, b = 13.594(5)Å, c = 15.999(6)Å, Z = 4, R₁ = 0.0609, wR₂ = 0.1328. The structure of 2 can be described as a one‐dimensional zigzag chain of Co^II ions bridged by one dca ligand. Each Co^II ion in the chain is coordinated by two bpm ligands. Compound 3 crystallizes in the monoclinic system, space group C₂, a = 13.559(15)Å, b = 7.393(8)Å, c = 8.110(9)Å, β = 112.228(15), Z = 2, R₁ = 0.0260, wR₂ = 0.0760. 3 has a one‐dimensional linear chain of Co^II ions bridged by two dca ligands, in which each Co^II ion is coordinated with two dmf molecules.     

Crystal structure and magnetic properties of a linear tetranuclear CoII cluster

Polynuclear complexes are an important class of inorganic functional materials and are of interest particularly for their applications in molecular magnets. Multidentate chelating ligands play an important role in the design and syntheses of polynuclear metal clusters. A novel linear tetranuclear Co^II cluster, namely bis{μ₃‐(E)‐2‐[(2‐oxidobenzylidene)amino]phenolato}bis{μ₂‐(E)‐2‐[(2‐oxidobenzylidene)amino]phenolato}bis(1,10‐phenanthroline)tetracobalt(II), [Co₄(C₁₄H₁₁NO₂)₄(C₁₂H₈N₂)₂], was prepared under solvothermal conditions through a mixed‐ligand synthetic strategy. The structure was determined by X‐ray single‐crystal diffraction and bulk purity was confirmed by powder X‐ray diffraction. The complex molecule has a centrosymmetric tetranuclear chain‐like structure and the four Co^II ions are located in two different coordination environments. The Co^II ions at the ends of the chain are in a slightly distorted octahedral geometry, while the two inner Co^II ions are in five‐coordinate distorted trigonal bipyramidal environments. A magnetic study reveals ferromagnetic Co^II…Co^II exchange interactions for the complex.     

A novel (E,E)-dioxime and its mono-, di- and trinuclear complexes bearing tetradentate octyl sulfanyl phenylamino substituents. Synthesis,characterization and electrochemical properties of its transition metal complexes

A new vic-dioxime, 13,14-bis-(hydroxyimino)-9,12,15,18-diazadithiaoctacosane, has been synthesized from 2-octylsulfanylaminobenzene and (E,E)-dichloroglyoxime. Mononuclear transition metal complexes of Ni^II, Cu^II, Co^II and Fe^II have been prepared and were found to have a metal–ligand ratio of 1:2. The synthesis of di- and trinuclear complexes was achieved with U^IVO₂ and Cu^II depending on the stoichiometry of the reactants. The complexes were characterized by elemental analysis, ¹H-n.m.r., u.v.–vis, i.r., f.a.b.-m.s. and by cyclic voltammetry.     

Manganese,cobalt and nickel complexes with a novel 17-membered macrocycle containing an N5 donor set

Summary The synthesis of a new macrocycle containing phenanthroline and pyridine subunits is described. The reaction of 2,9-bis(hydrazone)-1,10-phenanthroline with 2,6-bis-(bromomethyl) pyridine in the presence of Mn^II, Co^II or Ni^II ion templates leads to the isolation, in high yield, of the seven-coordinate complexes [M(L³)Br₂] (L³ = 4,5, 6,7,8,9-phenanthrolino-14,15,16-pyridino-1,2,5,8,11,12,15 heptaazacycloheptadecane,2,10-diene). The compounds were characterized by physical measurements, which indicated that in all the complexes the ligand is acting as a pentadentate N₅ chelating agent.     

Thermal decomposition of dinuclear complexes LM(μ-OOCR)<Subscript>4</Subscript>ML (L is α-substituted pyridine)

The solid-state thermal decomposition of the tetrabridged dinuclear Mn^II, Fe^II, Co^II, Ni^II, and Cu^II pivalate complexes with apical α-substituted pyridine ligands containing different substituents (2,3-dimethylpyridine or quinoline) was studied by differential scanning calorimetry and thermogravimetry. The decomposition of the Co^II complexes is accompanied by the aggregation to form the volatile octanuclear complex Co₈(μ₄-O)₂(μ_n-OOCCMe₃)₁₂, where n = 2 or 3, whereas the thermolysis of the Mn^II, Fe^II, Ni^II, and Cu^II complexes is accompanied by the degradation of the starting compounds, the phase composition of the decomposition products being substantially dependent on the nature of metal and the apical organic ligand. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1650–1659, September, 2007.     

Metal(II) complexes and metal(II) salts ofN-carbamoylpyrazole: N,O and N,N coordination

Summary Several new coordination compounds are reported withN-carbamoylpyrazole (Hcpz) as the ligand;viz. M(cpz)₂ where M = Cu^II and Ni^II; M(Hcpz)Cl₂ where M = Mn^II, Co^II, Cu^II, Zn^II and Cd^II; M(Hcpz)₂Cl₂ Where M = Fe^II, Co^II and Ni^II: M(Hcpz)₃(BF₄)₂ where M = Fe^II, Co^II, Ni^II, Zn^II and Cd^II; and Cu(Hcpz)₂(BF₄)₂. In the salts, Hcpz is coordinated through the nitrogen atoms of the pyrazole ring and the nitrogen atom of the carbamoyl group. In the Hcpz complexes, coordination takes place through the nitrogen atom of the pyrazole ring and the oxygen atom of the carbamoyl group.     

Synthesis,characterization and redox properties of a new vic-dioxime and its transition metal complexes

A novel vic-dioxime, 1,2 dihydroxyimino-1-p-tolyl-3-aza-6-morpholine heptane (LH₂) was prepared by reacting anti-p-tolylchloroglyoxime with 4-(3-aminopropyl)morpholine in absolute THF. Mononuclear complexes with a metal–ligand ratio of 1:2 were prepared using Co^II, Cu^II and Ni^II salts. The ligand and its complexes were characterized by elemental analyses, FT-IR, u.v.–vis., ¹H- and ¹³C-n.m.r. spectra, magnetic susceptibility measurements, thermogravimetric analyses (t.g.a.), and by cyclic voltammetry.     

A water-soluble multisite ionophore ligand bearing pyridine and aminothiophenol functionality. Synthesis, spectroscopy and electrochemistry of its complexes, and peripheral reactivity of the (E,E)M (M = Ni) complex with Pd2+ and Ag+

The design, synthesis and coordination of a novel multisite vic-dioxime compound, LH₂, containing flexible pyridine substituents and aminophenylsulfanyl moieties on the periphery, facilitating solubility in water as pyridinium hydrochloride salt are described. LH₂ was prepared by the reaction between 2-(2-pyridylethylamino)-benzenethiol and (E,E)-dichloroglydioxime. Mononuclear [(E,E)M] (M=Ni^II, Cu^II, Co^II, Fe^II and Mn^II) and dinuclear uranyl (UO₂ ^II) complexes of LH₂ were isolated and characterized with metal:ligand ratios of 1:2 and 2:2, respectively. The reaction of Na₂PdCl₄·3H₂O and AgNO₃ in DMF with the mononuclear complex, (LH)₂Ni, resulted in the formation of the heterotrinuclear complexes [Pd₂Ni(LH)₂]Cl₄ and [Ag₂Ni(LH)₂](NO₃)₂. The complexes were characterized by elemental analysis, ¹H-n.m.r., u.v.--vis. spectroscopy, i.r., and MS (LSIMS). The redox properties of the complexes were studied by cyclic voltammetry.     

New metal compounds and their reactivity towards bovine milk casein

The l,2-bis(sulphapyridyl)oxamide ligand [L] and its complexes with Fe^III, Co^II, Cu^II and Zn^II chloride were synthesized and characterized by elemental analyses, i.r., n.m.r., e.p.r. and u.v.–vis. spectroscopy and molar conductance measurements. Spectroscopic studies show that all the complexes are octahedral and covalent. The electrochemical behaviour of the Co^II complex was monitored by cyclic voltammetry in a buffer/DMF solution (95:5). The E ⁰ values –0.622 and –0.502 V reveal a reversible one electron redox wave attributed to a Co^II/Co^I redox couple at a scan rate of 0.1 V s^–1. The interaction of the Co^II complex with bovine milk casein (BMC) was studied at the same scan rate, which reveals a strong binding as the E ⁰ values shift to more negative potential (E ⁰ = –0.908 and –0.703 V). The cyclic voltammograms of the Co^II complex bound by BMC were recorded at different pH's. The plot of E ⁰ versus pH showed that E ⁰ values are maximal at pH 7.4 indicating good interaction between the BMC and the Co^II complex which is further confirmed by kinetic data. The kinetic studies of the Co^II complex bound to BMC was monitored in phosphate buffer solution at different pH's by spectrophotometry. The absorbance changes were monitored at 278 nm ( _max for BMC) with respect to time and pseudo-first-order rate constants, K _obs, were obtained from the slope and intercept of the straight line using the least squares regression method. The plot of absorbance versus time at different pH's was linear up to 80% completion of the reaction. The pH-rate profile data reveals that the reactions are pH dependent.     

Thermolyse von Cyanokomplexen. VII. Über die Thermischen Zersetzungsreaktionen der Hexacyanokobalte(III); Ligandenumlagerungen bei der Thermolyse

Thermolysis of cyano complexes. VII. On the thermal decomposition of hexacyanocobaltate(III); ligand exchange during thermolysis The thermal decomposition of hexacyanocobaltates(III) yields, as products of successive intramolecular redox reactions, first dicyan and Co^II(Co^III)-complexes, then Co^II[Co^II]-complexes and simple Co^II(CN)₂, respectively, and finally Co^ICN and elemental Co, respectively. All the compounds of the [Co^III(NH₃)₆]³⁺ cation with the cyanometallate anions of Co, Fe, Cr, Mn, Ni, Mo yield the same DTA curve as [Co(NH₃)₆][Co(CN)₆] does; in the case of Ni and Cr, which are capable of forming ammine complexes, simultaneous mutual ligand exchange occurs.     

Synthesis and structural characterization of nitrite-coordinating CoII and CoIII complexes as models for the reaction center of Co-substituted nitrite reductase

Co^II and Co^III complexes containing nitrite and tridentate aromatic amine compounds [bis(6-methyl-2-pyridylmethyl)amine (Me₂bpa) and bis(2-pyridylmethyl)amine (bpa)] have been prepared as models of the catalytic center in Co-substituted nitrite reductase: [Co^II(Me₂bpa)(NO₂)Cl]₂ · acetone (2), Co^II(Me₂bpa)(NO₂)₂ (3), Co^II(bpa)(NO₂)Cl (4), Co^II(bpa)(NO₂)₂ (5), Co^III(Me₂bpa)(NO₂)(CO₃) (6), and Co^III(bpa)(NO₂)₃ (7). The X-ray crystal structure analyses of these Co^II and Co^III complexes indicated that the geometries of the cobalt centers are distorted octahedral and the Me₂bpa and bpa with three nitrogen donors exhibit mer- (2, 3, and 7) and fac-form (4 and 6). The coordination mode of nitrite depends on the cobalt oxidation state, to Co^II through the oxygen (nitrito coordination, O- and O,O-coordination) and to Co^III through nitrogen (nitro coordination, N-coordination mode). These findings are consistent with the results of their IR spectra, except that another oxygen of the O-coordinated nitrito group in 3 might interact weakly with Co^II according to its IR spectrum. Reductions of the nitrite in 2, 3, 4, and 5 to nitrogen monoxide were not accelerated in the presence of proton, perhaps due to the nitrito coordination in these Co^II complexes.     

Synthesis,spectroscopic characterization and DFT study of dinuclear ruthenium sawhorse-type complexes derived from the reaction of trinuclear aggregates and (Z)-5-arylidenerhodanines

The synthesis of dinuclear ruthenium sawhorse-type complexes [Ru₂(μ-ArCH:Rhod)₂(CO)₄]_n 12a–e and [Ru₂(ArCH:Rhod)₂(μ-ArCH:Rhod)₂(CO)₄] 13a–e through reaction of [Ru₃(CO)₁₀(NCMe)₂] and [Ru₃(CO)₁₂] and the corresponding (Z)-5-arylidenerhodanines (ArCH:Rhod) 10a–e, respectively, are reported. These complexes are arranged in a sawhorse structure in which two bridged (Z)-5-arylidenerhodanines coordinate to the metals using sulfur and nitrogen of the rhodanine ring. A Density Functional Theory method was used to gain insight into the polymerization process by calculating dimerization Gibbs energies (ΔG_dim). Values between ?10.7 and ?5.3 kcal mol^?1 indicate that dimerization is a spontaneous process. A reaction pathway for formation of the sawhorse compounds [Ru₂(μ-ArCH:Rhod)₂(CO)₄] was calculated and the rate-determining step for the mechanism is coordination of a second (Z)-5-arylidenerhodanine ligand with activation energies between 41.1 and 47.8 kcal mol^?1. In order to understand the apparent thermodynamic favorability of the fragmentation step, we calculated the fragmentation energy (ΔE_Frag) for the key intermediate and its energetic contributors, the interaction energy, ΔE_int and the reorganization energy, ΔE_reorg. Low values of ΔE_Frag imply that the fragmentation is thermodynamically facile. Large values of ΔE_int are countered by opposite and large values of ΔE_reorg which indicate that the cleavage of the trimetallic intermediate aggregate is determined by the nature of the ligand and the balance between its interaction with the metal and the extent of structural reorganization.     

Alcohol-soluble functional vic-dioxime bearing alcoholhexylsulfanyl moieties: preparation, spectroscopy and electrochemistry

A new alcohol soluble functionalized vic-dioxime, bis-[(1-hydroxyhexyl)-(8,9-hydroxyimino)-7,10-dithiahexacosane (LH₂), and its alcohol-soluble mono and dinuclear complexes (Ni^II, Cu^II, Co^II, Mn^II, Pd^II and UO ₂ ^II ) have been prepared from 6-mercapto-1-hexanol and (E,E)-dichloroglyoxime under high dilution basic conditions. Reactive polyalcohol moieties appended at the periphery of the oxime containing two different heteroatoms (S-, O-), serve as a weak exocyclic binding sites for Pd^II and Ag^I metal ions and also provide solubility for the vic-dioxime complexes in low molecular-weight alcohols. Both mono-nuclear (LH)₂M and homodinuclear (LH)₂(UO₂)₂(OH)₂ and heterotrinuclear (LH)₂MM ₂ ^′ Xn, where M = Co^II M′ = Pd^II, X = Cl⁻, n = 4 and Ag^I X = NO ₃ ⁻ , n = 2) complexes have been obtained with a 1:2, 2:2, 3:2 metal/ligand ratio, respectively. Electronic spectra of the modified vic-dioximes exhibit monitorable changes in UV. All mono and dinuclear-complexes are soluble in common organic solvents. The elemental analysis, ¹H-n.m.r, i.r., u.v–vis, and f.a.b.–m.s data and by cyclic and differential pulse voltammetry measurements are presented.     

Entrapment of a Pseudo‐Tetrahedral CoII Center by Thioether Sulfur Bound {Co2(μ‐L)} Fragments: Synthesis,Field‐Induced Single‐Ion Magnetism and Catechol Oxidase Mimicking Activity

Simultaneous incorporation of both Co^II and Co^III ions within a new thioether S‐bearing phenol‐based ligand system, H₃L (2,6‐bis‐[{2‐(2‐hydroxyethylthio)ethylimino}methyl]‐4‐methylphenol) formed [Co₅] aggregates [Co^IICo^III₄L₂(μ‐OH)₂(μ_1,3‐O₂CCH₃)₂](ClO₄)₄?H₂O ( 1 ) and [Co^IICo^III₄L₂(μ‐OH)₂(μ_1,3‐O₂CC₂H₅)₂](ClO₄)₄?H₂O ( 2 ). The magnetic studies revealed axial zero‐field splitting (ZFS) parameter, D/hc=?23.6 and ?24.3 cm^?1, and E/D=0.03 and 0.00, respectively for 1 and 2 . Dynamic magnetic data confirmed the complexes as SIMs with U_eff/k_B=30 K ( 1 ) and 33 K ( 2 ), and τ₀=9.1×10^?8 s ( 1 ), and 4.3×10^?8 s ( 2 ). The larger atomic radius of S compared to N gave rise to less variation in the distortion of tetrahedral geometry around central Co^II centers, thus affecting the D and U_eff/k_B values. Theoretical studies also support the experimental findings and reveal the origin of the anisotropy parameters. In solutions, both 1 and 2 which produce {Co^III₂(μ‐L)} units, display solvent‐dependent catechol oxidation behavior toward 3,5‐di‐tert‐butylcatechol in air. The presence of an adjacent Co^III ion tends to assist the electron transfer from the substrate to the metal ion center, enhancing the catalytic oxidation rate.     

Synthesis and characterization of CuII and CoII complexes derived from 2,4,6-tri-(2-pyridyl)-1,3,5-triazine (TPT) by chemical and tribochemical reactions

Four Cu^II and Co^II complexes–[Cu(L₁)Cl₂(H₂O)]3/2H₂O · 1/2EtOH, [Cu(L₁)₂Cl₂]6H₂O, [Co(L₁)Cl₂]3H₂O · EtOH, and [Co₂(L₁)(H₂O)Cl₄]1.5H₂O · EtOH (L₁ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine; TPT)–were synthesized by conventional chemical method and used to synthesize another four metal complexes–[Cu(L₁)I₂(H₂O)]6H₂O, [Cu(L₁)₂I₂]6H₂O, [Co(L₁)I(H₂O)₂]I · 2H₂O, and [Co₂(L₁)I₄(H₂O)₃]–using tribochemical reaction, by grinding it with KI. Substitution of chloride by iodide occurred, but no reduction for Cu^II or oxidation of Co^II. Oxidation of Co^II to Co^III complexes was only observed on the dissolution of Co^II complexes in d₆-DMSO in air while warming. The isolated solid complexes (Cu^II and Co^II) have been characterized by elemental analyses, conductivities, spectral (IR, UV-Vis, ¹H-NMR), thermal measurements (TGA), and magnetic measurements. The values of molar conductivities suggest non-electrolytes in DMF. The metal complexes are paramagnetic. IR spectra indicate that TPT is tridentate coordinating via the two pyridyl nitrogens and one triazine nitrogen forming two five-membered rings around the metal in M : L complexes and bidentate via one triazine nitrogen and one pyridyl nitrogen in ML₂ complexes. In binuclear complexes, L is tridentate toward one Co^II and bidentate toward the second Co^II in [Co₂(L₁)Cl₄]2.5H₂O · EtOH and [Co₂(L₁)I₄(H₂O)₃]. Electronic spectra and magnetic measurements suggest a distorted-octahedral around Cu^II and high-spin octahedral and square-pyramidal geometry around Co^II.     

The synthesis and characterization of ( E,E )-dioxime and its transition metal complexes containing 12-membered macrocycles linked to ferrocenyl-methyl groups

13,14-bis(Hydroxyimino)-4,7-bis(ferrocenylmethyl)-2,3,4,5,6,7,8,9-octahydrobenzo[k]-4, 7-diaza-1,10-dithiacyclododecine[13,14-g]-quinoxaline (H₂L) has been prepared from (E,E)-dichloroglyoxime and 12,13-diamino-4,7-bis(ferrocenylmethyl)-2,3,4,5,6,7,8,9-octahydrobenzo[k]-4,7-diaza-1,10-dithiacyclododecine which was synthesized from 12,13-dinitro-4,7-bis(ferrocenylmethyl)-2,3,4,5,6,7,8,9-octahydrobenzo[k]4,7-diaza-1,10-dithia cyclododecine. Mononuclear nickel(II) and copper(II) complexes of H₂L have a metal-ligand ratio of 1?:?2 and the ligand coordinates through two nitrogen atoms, as do most (E,E)-dioximes. The homotrinuclear [Cu(L)₂Cu₂(dipy)₂](NO₃)₂ compound coordinates to the other two copper(II) ions through deprotonated oximate oxygens and two 2,2′-dipyridyl as an end-cap ligand to yield the trinuclear structure. The ligand and its complexes have been characterized on the basis of ¹H, ¹³C NMR, IR and MS spectroscopy and elemental analyses.