Magnetic properties of new complexes of 3d metal chlorides with 3-amino-4-ethoxycarbonylpyrazole

New complexes of Co(II), Ni(II), and Cu(II) chlorides with 3-amino-4-ethoxycarbonylpyrazole (L) of the composition ML₂Cl₂ are synthesized. The compounds are studied by powder X-ray diffraction, electronic and IR spectroscopy, static magnetic susceptibility (temperature range 2–300 K). It is found that in the ML₂Cl₂ complexes (M = Co(II), Ni(II), Cu(II)) ferromagnetic exchange interactions between the unpaired electrons of metal ions occur. In [CoL₂Cl₂] and [NiL₂Cl₂] compounds a transition to the magnetically ordered state (T _c ? 10–12 K) is observed.     

Synthesis and photosensitizing properties of fluoroalkoxyl phthalocyanine metal complexes

Nine fluoroalkoxyl phthalocyanine metal complexes (Zn, AlCl, Mg, Co, Cu, FeCl) were synthesized from 4-(polyfluoroalkoxyl) phthalic anhydride. The fat-soluble phthalocyanines were characterized by elemental analysis, IR, ¹H NMR and fast-atom-bombardment mass spectroscopy. Zinc and aluminum chloride complexes show higher photooxidation ability in solution containing 20% perfluorocarbons than in hydrocarbon solvents.     

Low-temperature synthesis of phthalocyanine and its metal complexes

Conditions for synthesizing unsubstituted phthalocyanine and its metal complexes from phthalonitrile at low temperatures (0–50°C) are optimized. Phthalocyanine and phthalocyaninates are produced under these conditions using activated Rieke metals, metals on inert substrate, sources of “soluble” metals in the form of unstable metal complexes, zeolites, solid-phase electrosynthesis of phthalonitrile, and UV irradiation. The use of pyrophoric metals is found to be the most efficient due to a large number of defects in their structure favoring the initial stage of phthalonitrile cyclization on a metal matrix. The suggested mechanism of formation of phthalocyanine macrocycle assumes participation of metal agglomerates occurring in activated metals.     

Preparation and properties of electron donor acceptor complexes of the compounds having capto-dative substituents

In order to examine the “capto-dative” substitution-effect on the electrical conductivity, five compounds which have capto-dative substituents were prepared. Electron withdrawing (capto) group was nitro- or cyano-substituted phenyl and electron donating (dative) one was 5-methyl-5,10-dihydrophenazinyl moiety. The character of intramolecular electron donor acceptor complex of the five compounds were demonstrated by their uv spectra. Electron donor acceptor complexes of them with tetracyanoquinodimethane were prepared and their electrical resistivities were measured.     

Investigated aerobic oxidation of aminochlorophenol catalyzed by phthalocyanine complexes

The synthesis of 9-Octadecenamide substituted Fe(II) phthalocyanine (ODAFePc) and Ni(II) phthalocyanine (ODANiPc) complexes from Fe(II) tetracarboxylic acid phthalocyanine (FeTcPc) and Ni(II) tetracarboxylic acid phthalocyanine (NiTcPc) with 9-Octadecenamide. These complexes have high molecular weight and soluble in organic solvents. The complexes have been confirmed by FTIR, Mass spectroscopy, UV–Visible X-ray diffraction, and thermogravimetric analysis. The synthesized complexes exhibit excellent stability and are catalytically active in 2-amino-4-chlorophenol (ACP) oxidation. The new method was used for the determination of the oxidation of phenol by applying different experimental parameters like concentration, catalytic quantity, temperature, and pH to get a good yield and catalytic activity of ODAFePc and ODANiPc were studied. ACP was oxidized by dissolved oxygen with ODAFePc and ODANiPc as a catalyst and immediately combined with 4-aminoantipyrine (4-AAP) to form a pink dye and was determined by appearance of absorption intensity at 580 ​nm. All the experimental results show that ODAFePc and ODANiPc complexes exhibit good catalytic behavior on oxidation of 2-amino-4-chlorophenol.     

Quinoxaline 1-oxide complexes with transition metal chlorides[1]

3d metal chloride complexes with quinoxaline 1-oxide (NQxO) were prepared by allowing ligand and salt solutions, pretreated with molecular sieve 4A, to interact. Complexes of the following stoicheiometries were obtained: (CrCl₃)(NQxO)₃·12H₂O, MNCl₂(NQxO)₂, (FeCl₃)(NQxO)₃·2H₂O, CoCl₂(NQxO)₃·5H₂O, NiCl₂(NQxO)₂, CuCl₂(NQxO)₂·3H₂O and ZnCl₂(NQxO). Characterization of the new metal complexes was based on spectral and magnetic studies. The overall evidence suggests that these compounds are bi- or poly-nuclear. Likely structures involve: Both terminal and bridging unidentate O-bonded NQxO and chloro ligands for the Cr(III) and Fe(III) complexes; chloride bridging and exclusively therminal NQxO for the Mn(II), Ni(II), and Cu(II) compounds; NQXO appears to be O-bonded in the Mn(II) and N-bonded in the Ni(II) and Cu(II) complexes; the Zn(II) complex contains terminal chloro and bridging dibentate, O, N-bonded NQxO; and the Co(II) compound appears to involve both terminal, N-bonded, and bridging bidentate, O, N-bonded NQxO. The Zn(II) complex is probably tetrahedral, the Mn(II) compound pentacoordinated, and the rest of the new complexes hexacoordinated. With the exception of the Fe(III) complex, which probably involves spin-free-spin-paired equilibria (μ_eff = 3.71 BM), the new metal complexes are magnetically normal high-spin compounds.     

Self-exchange electron transfer in high oxidation state non-oxo metal complexes: amavadin

The electron transfer self-exchange rate constant between the oxidized and reduced forms of amavadin equals approximately 1 x 10(5) dm3 mol(-1) s(-1) at 25 degrees C and represents the first unambiguous example for a vanadium(IV/V) couple.     

Magnetic properties of transition metal complexes with 2,2′-bipyridin-5-yl t-butyl nitroxide

Complexes [Mn^II(5bpno)₃(ClO₄)₂], [Mn^II(5bpno)(CH₃OH)₂Cl₂], [Cu^II(5bpno)₂(ClO₄)₂], and [Cu^II(5bpno)Cl₂] were prepared, where 5bpno stands for 2,2′-bipyridin-5-yl t-butyl nitroxide. X-ray crystallographic analysis clarified that the Cu ion in [Cu(5bpno)₂(ClO₄)₂] was tetra-coordinate with four nitrogen atoms forming two chelate rings. Magnetic measurements revealed the presence of ferromagnetic couplings in the Mn complexes, whereas the Cu complexes showed antiferromagnetic couplings. Magnetic exchange couplings between the metal and radical spins through the intervening pyridine ring can be explained in terms of the spin-polarization mechanism.     

Synthesis and spectral properties of europium phthalocyanine complexes

Methods for the synthesis of europium complexes with phthalocyanine and thenoyltrifluoroacetonate (tta) or ferrocenoyltrifluoroacetonate (fta) ligands are discussed. The spectral characteristics of the complexes PcEu(tta)(ttaH) and PcEu(fta)(ftaH) (Pc is phthalocyanine) are studied.     

Catalytic properties of cobalt complexes with tetrapyrazino porphyrazine and phthalocyanine derivatives

The catalytic activity of cobalt complexes with octaphenyltetrapyrazinoporphyrazine and phthalocyanine derivatives containing branched peripheral substituents is studied in heterogeneous catalysis of the oxidation of sodium diethyldithiocarbamate (SDC) with atmospheric oxygen. Cobalt phthalocyanines are shown to display higher catalytic activity than cobalt complexes with octaphenyltetrapyrazinoporphyrazine. The highest efficiency of heterogeneous catalysts is attained at temperatures of 298–303 K.     

Synthesis and photophysical properties of metal anthraquinone phthalocyanine

A novel anthraquinone phthalocyanine Al(Ⅲ) 4 and Co(Ⅱ) 5 were synthesized and characterized by elemental analysis, IR, UV/ vis, 1H NMR, HPLC and MS. The photophysical properties of the two metal complexes were studied and compared by ?uorescence spectrum method.     

Synthesis and spectral properties of lanthanide double-decker complexes with tetrabenzoporphyrin and phthalocyanine

Mixed-ligand double-decker complexes containing tetrabenzoporphyrin and phthalocyanine fragments were synthesized by reaction of phthalocyanine dilithium salt with tetrabenzoporphyrin complexes of lutetium, dysprosium, gadolinium, neodymium, and lanthanum. A relation was found between spectral parameters of the obtained sandwich complexes and radii of the central metal ions.     

Resorufin as an electron acceptor in glucose oxidase-catalyzed oxidation of glucose

Resorufin (1) has been found to act as an electron acceptor in glucose oxidase (GOD)-catalyzed oxidation of glucose. When a 1: 1: 1 mixture of solutions of 1 (5.0 microM), glucose, and GOD (4.0 mg/ml) in phosphate buffer (pH 7.4, 0.1 M) was incubated at 36 degrees C under aerobic conditions and the reaction was followed by a measurement of changes in fluorescence intensity due to 1, only two types of fluorometric traces were observed: (1) when a glucose solution of less than 0.7 mM was subjected to the enzymatic reaction, no consumption of 1 was observed; (2) the reaction with glucose at more than 1.0 mM always consumed 1, affording a regression fluorometric curve, and yet the obtained fluorometric traces could be almost superimposed on one another with no dependence on the glucose concentration. The reasons for the observed phenomena are discussed.     

Resazurin as an electron acceptor in glucose oxidase-catalyzed oxidation of glucose

The behavior of resazurin (1) as an electron acceptor in glucose oxidase (GOD)-catalyzed oxidation of glucose under anaerobic conditions is described. When a mixture of 1, glucose, and GOD in phosphate buffer (pH 7.4, 0.1 M) was incubated at 25 degrees C, the resulting solution turned purple to fluorescent pink due to the deoxygenated product, resorufin (2). On incubation of 1 with GOD alone or with H2O2 under essentially the same conditions, no color change was seen, indicating that generation of 2 in the enzymatic reaction is brought about through reduction of 1 by the reduced form (GODred) of GOD, which was also supported by the voltammetric behavior of 1. However, it was found that the enzymatic transformation of 1 to 2 is of no practical use as an indicator reaction for glucose determination using only GOD due to a slow reaction of 1 with GODred. Based on a ping-pong type mechanism with a steady-state approximation, KM and kcat for 1 as an electron acceptor from GODred were estimated to be 15+/-1.3 microM and (5.0+/-0.5) x 10(-2) s(-1), respectively.     

Some peculiarities of metal exchange reactions in porphyrin and phthalocyanine complexes

Kinetics of metal exchange reaction Cd(II) Zn(II) and Cd(II) Cu(II) in Cd complexes with tetraphenylporphyrin in DMSO is studied. Reaction with Cu(II) nitrate occurs in both cases more vigorously as compared to that with Zn(II) nitrate. Conditions for metal exchange reactions are studied depending on the nature of metal porphyrinate, a salt (nitrates, acetates, and chlorides of Zn(II), Cu(II), and Co(II), and of organic solvent (DMSO, CH₃CN). It is shown that Zn(II) complexes with nonplanar porphyrins do not show metal exchange Zn(II) Cu(II) or Zn(II) Co(II) under mild conditions in DMSO and CH₃CN.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 104–109. Original Russian Text Copyright © 2005 by D. Berezin, Shukhto, Nikolskaya, B. Berezin.     

Magnetic properties of biacetyldihydrazone complexes

Summary Magnetic susceptibilities of the biacetyldihydrazone (BdH) complexes [M(BdH)₃](NO₃)₂ (M = Co^II, Ni^II, Cu^II or Zn^II), [Fe(BdH)₃](NO₃)₃, [M(BdH)₃](Ni(dto)₂] (M = Co^II, Ni^II or Zn^II; dto = dithiooxalate), [(BdH)₂Cu(dto)Ni(dto)] and [Fe(BdH)₃]₂[Ni(dto)₂]₃ have been studied in the 4.2–295 K range. Zn^II complexes are diamagnetic, and complexes of Ni^II, Cu^II and Fe^III obey the Curie-Weiss law. The Co^II complexes behave anomalously and the results are interpreted in terms of a high spinlow spin equilibrium.     

Synthesis and structure of tris(halo)alkyl phosphate complexes with metal chlorides

Complexes were prepared of some orthophosphoric acid esters with metal chlorides. The composition and structure of complexes synthesized were investigated by IR, ¹H and ³¹P NMR, mass spectroscopy, and XRD analysis.     

Electrophysical properties of metal nitrate complexes with polyacrylamide

The electrophysical characteristics of metallopolymers obtained by spontaneous polymerization of complexes of Er, Ca, and UO₂ nitrates with acrylamide were investigated. The conductivity () at direct current was measured (10^–5 to 10^–6 Ohm^–1 cm^–1), and its alterations during the polymerization were observed. The conductivity of the metallopolymers obtained depends essentially on the voltage applied during the polymerization and the component ratio in the original mixture. It is concluded that the conductivity is ionic in character. The conductivity and the electret properties discovered depend on the moisture content of the samples.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 865–867, May, 1994.