Synthesis,characterization, and crystal structure of three cobalt(II) complexes with Schiff bases derived from rimantadine

By condensation of rimantadine and substituted salicylaldehyde, three new Schiff bases, HL¹, HL² and HL³, were synthesized. Then, a mixture of one of the new ligands and cobalt(II) chloride hexahydrate in ethanol led to 1, 2, and 3, respectively. These complexes were characterized by melting point, elemental analysis, infrared spectra, molar conductance, thermal analysis, and single-crystal X-ray diffraction analysis. X-ray diffraction analysis reveals that 1 crystallizes in the orthorhombic system, Pbcn space group; each asymmetric unit consists of one cobalt(II) ion, two deprotonated ligands, and one lattice water. The central cobalt is four coordinate via two nitrogens and two oxygens from the corresponding Schiff base ligand, forming a distorted tetrahedral geometry. Complexes 2 and 3 crystallize in the monoclinic system, P2₁/c space group; each asymmetric unit consists of one cobalt(II), two corresponding deprotonated ligands, one lattice water, and one methanol. The central cobalt is also four-coordinate via two nitrogens and two oxygens from the corresponding Schiff base ligand, forming a distorted tetrahedral geometry.     

Studies on mononuclear chelates derived from substituted Schiff-base ligands (part 6): synthesis and characterization of a new 3-ethoxysalicyliden- p -aminoacetophenoneoxime and its complexes with cobalt(II), nickel(II), copper(II) and zinc(II)

Schiff-base complexes of cobalt(II), nickel(II), copper(II) and, zinc(II) with 3-ethoxysalicyliden-p-aminoacetophenoneoxime (HL) were prepared and characterized on the basis of elemental analyses, IR, ¹H- and ¹³C-NMR, electronic spectra, magnetic susceptibility measurements, molar conductivity and thermogravimetric analyses (TGA). A tetrahedral geometry has been assigned to the complexes.     

Three new pseudohalide bridged dinuclear Zn(II) Schiff base complexes: Synthesis,crystal structures and fluorescence studies

Three new dinuclear Zn(II) complexes [Zn(L)(μ_1,1-N₃)Zn(L)(N₃)] · 1.5H₂O (1), [Zn(L)(μ_1,1-NCO)Zn(L)(NCO)] · 1.5H₂O (2) and [Zn(L)(μ_1,1-NCS)Zn(L)(NCS)(OH₂)] (3) have been synthesized from a potentially tetradentate N₂O₂-donor Schiff base ligand LH, [LH = (OCH₃)(OH)C₆H₃CHN(CH₂)₂N(CH₃)₂], which is the condensation product of o-vanillin and 2-dimethylaminoethylamine. All the three complexes 1, 2 and 3 have been characterized by elemental analysis, IR and ¹H NMR spectroscopy, TGA and fluorescence studies. Finally, their structures have been established by the single crystal X-ray diffraction method. Structural studies reveal that in complexes 1, 2 and 3 the two Zn(II) centers are held together by a μ₂-phenolato oxygen atom and also by an end-on pseudohalide nitrogen (azide for 1; cyanate for 2; thiocyanate for 3) atom. Among the two deprotonated Schiff base ligands present in each complex, one acts as a tetradentate ligand (N₂O₂ donor set) while the other acts as a tridentate ligand (N₂O donor set), having a non-coordinated methoxy group. All the synthesized complexes display intraligand ¹(π–π^∗) fluorescence and can potentially serve as photoactive materials.     

The structures and cyclic voltammetry of three copper(II) complexes derived from bulky ortho-hydroxy Schiff bases

Three copper(II) complexes derived from bulky ortho-hydroxy Schiff base ligands, (1)-(3), were synthesized and characterized by chemical analysis, UV-Vis, IR, μ_eff and mass spectrometry. The solid state structures of compounds (1)-(3) were determined. The solid state X-ray diffraction studies of these compounds show that the geometry is intermediate between square planar and tetrahedral. Moreover, EPR studies in DMF solution at 77 K suggest that the geometry of these complexes in solution is different from that observed in the solid state by X-ray crystallography. Furthermore, cyclic voltammetry studies performed for (1)-(3), indicate a dependence of the cathodic potentials upon conformational and electronic effects.     

Syntheses,crystal structures,and antibacterial activities of manganese(III), nickel(II), and copper(II) complexes containing a tetradentate Schiff base

Three new mononuclear Schiff-base complexes, namely [Mn(L)Cl] (1), [Ni(L)] (2), and [Cu(L)] (3), where L?=?anion of [N,N′-bis(2-hydroxybenzophenylidene)]propane-1,2-diamine, have been synthesized by reacting equimolar amounts of the respective metal chloride and the tetradentate Schiff base, H₂L, in methanol. The complexes have been characterized by microanalytical, spectroscopic, single-crystal X-ray diffraction, and other physicochemical studies. Structural studies reveal that 1 adopts a distorted square-pyramidal geometry whereas 2 and 3 are isotypic with distorted square-planar geometries. The antibacterial activities of 1–3 along with their Schiff base have been tested against some Gram(+) and Gram(?) bacteria.     

Synthesis, crystal structure, spectroscopic and photoluminescence studies of manganese(II), cobalt(II), cadmium(II), zinc(II) and copper(II) complexes with a pyrazole derived Schiff base ligand

Varying coordination modes of the Schiff base ligand H₂L [5-methyl-1-H-pyrazole-3-carboxylic acid (1-pyridin-2-yl-ethylidene)-hydrazide] towards different metal centers are reported with the syntheses and characterization of four mononuclear Mn(II), Co(II), Cd(II) and Zn(II) complexes, [Mn(H₂L)(H₂O)₂](ClO₄)₂(MeOH) (1), [Co(H₂L)(NCS)₂] (2), [Cd(H₂L)(H₂O)₂](ClO₄)₂ (3) and [Zn(H₂L)(H₂O)₂](ClO₄)₂ (4), and a binuclear Cu(II) complex, [Cu₂(L)₂](ClO₄)₂ (5). In the complexes 1-4 the neutral ligand serves as a 3N,2O donor where the pyridine ring N, two azomethine N and two carbohydrazine oxygen atoms are coordinatively active, leaving the pyrazole-N atoms inactive. In the case of complex 5, each ligand molecule behaves as a 4N,O donor utilizing the pyridine N, one azomethine N, the nitrogen atom proximal to the azomethine of the remaining pendant arm and one pyrazole-N atom to one metal center and the carbohydrazide oxygen atom to the second metal center. The complexes 1-4 are pentagonal bipyramidal in geometry. In each case, the ligand molecule spans the equatorial plane while the apical positions are occupied by water molecules in 1, 3 and 4 and two N bonded thiocyanate ions in 2. In complex 5, the two Cu(II) centers have almost square pyramidal geometry (τ = 0.05 for Cu1 and 0.013 for Cu2). Four N atoms from a ligand molecule form the basal plane and the carbohydrazide oxygen atom of a second ligand molecule sits in the apex of the square pyramid. All the complexes have been X-ray crystallographically characterized. The Zn(II) and Cd(II) complexes show considerable fluorescence emission while the remaining complexes and the ligand molecule are fluorescent silent.     

Copper(II) complexes with neutral Schiff bases: Syntheses, crystal structures and DNA interactions

The synthesis and X-ray structural characterisation of a new Cu(II) complex, [Cu(L¹)Cl](ClO₄)·CH₃OH (1) [L¹ = N,N′-bis((pyridine-2-yl)phenylidene)-1,3-diaminopropan-2-ol], has been described in this work. The structural study reveals that the Cu(II) centre in 1 has a square pyramidal geometry with a trigonality index τ = 0.43, being coordinated by the organic ligand and a chloro group. The interaction of complex 1 and another complex previously reported by our group, [Cu(L²)](ClO₄)₂ (2) [L² = N-(1-pyridin-2-yl-phenylidene)-N′-[2-({2-[(1-pyridin-2-ylphenylidene)amino]ethyl}amino)ethyl]ethane-1,2diamine], with calf thymus DNA (CT-DNA) has been investigated using absorption and emission spectral studies. The binding constant (K_b) and the linear Stern-Volmer quenching constant (K_sv) have been determined.     

The crystal structures and electrochemical studies of two naphthalenic Schiff base copper(II) complexes

The Schiff base ligands, 2-hydroxy-N-cyclohexyl-l-naphthaldimine (I), and 3-hydroxy-N-cyclohexyl-2-naphthaldimine (II), and their corresponding Cu^II complexes (1–2) respectively were synthesized and characterized. The crystal and molecular structures of bis-{(cyclohexyl)[(2-oxo-1H-naphth-1-ylidene)-methyl]aminato}copper(II) (1) and bis-{(cyclohexyl)[(3-oxo-2H-naphth-2-ylidene)-methyl]aminato} copper(II) (2), were determined. The X-ray diffraction study shows that the geometry around the metal atom for (1), is stepped square planar with a step of 1.063 Å while for (2), the geometry around the metal atom for square planar with an angle between the coordination planes O(1)---Cu---N(1) and O(1a)---Cu---N(1a) of 39.9°. Electrochemical studies show a dependence of the Cu^II/Cu^I potentials on the ligand structure.     

Synthesis,crystal structure,and antimicrobial activity of a series of cobalt(III) Schiff base complexes

Abstract

A series of six new mononuclear Schiff base complexes, 1–6 of cobalt(III) of the general formula, [CoLX] or its adduct with methanol, is reported. The pentadentate Schiff base ligand (H₂L) was obtained by the condensation of N-(3-aminopropyl)-N-methylpropane-1,3-diamine with 1-(2-hydroxyphenyl)ethanone (H₂L¹) or 1-(2-hydroxyphenyl)propan-1-one (H₂L²). X stands for the pseudohalides, N₃^–, N(CN)₂^? , and NCS^–. The complexes have been synthesized by the reaction of equimolar amounts of cobalt(II) nitrate with H₂L¹ or H₂L² in the presence of the respective pseudohalide in methanol medium. All the complexes have been characterized by microanalytical, spectroscopic, single crystal XRD (except 3), and other physicochemical studies. Structural studies reveal that the central Co(III) ion in 1, 2, 4, 5, and 6 adopts a distorted octahedral geometry with a CoN₄O₂ chromophore. Weak intermolecular H-bonding and/or π-interactions are operative in these complexes to bind the molecular units. The antimicrobial activity of all the complexes and their constituent Schiff bases has been tested against some common bacteria and fungi.     

A rare ferromagnetically coupled asymmetric doubly azido bridged copper(II) dimer with an N,N, O donor Schiff base

A new end-to-end (EE) doubly azido bridged dinuclear complex [Cu₂L₂(μ_1,3-N₃)₂] (1) [where L = (E)-4-(2-(dimethylamino)ethylimino)-1,1,1-trifluoropentan-2-one)] has been synthesized and characterized by elemental and spectroscopic techniques. Single crystal X-ray diffraction analysis reveals that the dimeric complex possesses a center of inversion. Each copper atom in 1 is in a distorted square pyramidal geometry with a CuN₄O chromophore as revealed from the τ value, 0.19. The four basal positions are occupied by two imine N and one keto O atom of the Schiff base and one N atom from the azide anion. Another N atom from a coordinated azide occupies the apical position. Temperature dependent magnetic susceptibility of 1 was fitted using the Bleaney–Bowers expression which led to the parameters J = 13.6 cm⁻¹ and R = 3.4 × 10⁻⁵. It indicates a ferromagnetic interaction through the double azido bridges connecting the individual copper Schiff base units.     

Syntheses,characterization and X-ray crystal structures of Co(III) and Mn(II) complexes of pyrimidine derived Schiff base ligands

Two pyrimidine based NNS tridentate Schiff base ligands S-methyl-3-((2-S-methyl-6-methyl-4-pyrimidyl)methyl)dithiocarbazate [HL₁] and S-benzyl-3-((2-S-methyl-6-methyl-4-pyrimidyl)methyl)dithiocarbazate [HL₂] have been synthesised by 1:1 condensation of 2-S-methylmercapto-6-methylpyrimidine-4-carbaldehyde and S-methyl/S-benzyl dithiocarbazate. One Co(III) and one Mn(II) complex of HL₁ and one Mn(II) complex of HL₂ have been prepared and characterized by elemental analyses, molar conductivities, magnetic susceptibilities and spectroscopic studies. All the bis-chelate complexes have a distorted octahedral arrangement with an N₄S₂ chromophore around the central metal ion. Each ligand molecule binds the metal ion using pyrimidyl nitrogen, azomethine nitrogen and the thiolato sulfur atoms. In the free ligand moieties, the pyrimidine nitrogen atoms, azomethine nitrogen atoms and thione sulfur atoms are in EEE orientation to each other. During chelation, all the donor sites of the ligands are reoriented to ZEZ configuration in order to facilitate the chelation process. In all the complexes, the respective ligand molecule functions as the monoanionic tridentate one. All complexes were analyzed by single crystal X-ray diffraction and significant differences concerning the distortion from octahedral geometry of the coordination environment were observed.     

Synthesis,characterization and crystal structures of dinuclear macrocyclic Schiff base copper(I) complexes bearing different bridges

Utilizing a new 20-membered macrocyclic Schiff base ligand with two coordination sites formed from the [2+2] condensation of 1,3-diaminopropane and benzene-1,3-dicarboxaldehyde in the presence of CuX (X = Cl⁻, Br⁻, I⁻) salts, air-stable dicopper(I) complexes were synthesized in acetonitrile, intramolecularly linked via two halide groups, and characterized by different physico-chemical techniques. The single crystal X-ray diffraction technique indicates these complexes consist of two N₂X₂ donor sets that have distorted tetrahedral coordination environments around the copper(I) ions. In these halogen-bridged binuclear Cu₂LX₂ systems the Cu?Cu separation can be controlled, as this distance is reduced on increasing the halide size and hence the X?X repulsion, with the rigidity of the macrocycle playing a significant role.     

Polarized spectroscopy of hybrid materials of chiral Schiff base cobalt(II), nickel(II), copper(II), and zinc(II) complexes and photochromic azobenzenes in PMMA films

A chiral Schiff base complex, bis(N-R-1-phenylethyl-3,5-dichlorosalicydenaminato) cobalt(II) was prepared newly and characterized to be a distorted tetrahedral trans-[CoN₂O₂] coordination geometry. Organic/inorganic hybrid materials containing the related cobalt(II), nickel(II), copper(II), and zinc(II) complexes and photochromic azobenzene in polymethylmethacrylate (PMMA) cast films were assembled for comparison of their flexibility and molecular arrangement in the photofunctional medium. Characterization of each component and hybrid materials was carried out by means of absorption and CD spectra and thermal analysis (TG–DTA and DSC). Moreover, we have attempted to observe changes of conformation and/or molecular arrangement of the complexes or azobenzene induced by cis–trans photoisomerization of azobenzene after alternate irradiation of polarized UV and visible light. Gradual increase of optical anisotropy was observed for all the hybrid materials regardless of flexibility of Schiff base complexes, and the degree of dichroism and weak intermolecular interactions were discussed based on polarized absorption electronic spectra.     

Syntheses,crystal structures,and antibacterial activities of two cobalt(III) complexes

Syntheses, structures, and antimicrobial activities of cobalt(III) complexes with two tetradentate Schiff-base ligands, (BA)₂en?=?bis(benzoylacetone)ethylenediimine dianion and (acac)₂en?=?bis(acetylacetone)ethylenediimine dianion, and two axial pyridines (py) have been investigated. These complexes were characterized by FT-IR, ¹H-NMR, UV-Vis spectroscopy, and elemental analysis. The crystal structures of the complexes were determined by X-ray crystallography. Single-crystal X-ray diffraction analyses revealed that both complexes have distorted octahedral environments, Schiff-base ligand coordinates cobalt in four equatorial positions, and the two axial positions are occupied by pyridines. The pyridines and Schiff-base ligands are involved in N–H···O hydrogen bonds with perchlorate. Biological activities of the ligands and metal complexes have been studied on Staphylococcus aureus, Escherichia coli, and Bacillus subtilis by the well diffusion method. The activity data show the metal complexes to be more potent than the parent ligand against two bacterial species.     

Synthesis, X-ray crystal structures, spectroscopic and cyclic voltammetric studies of Cu(II) Schiff base complexes of pyridoxal

Two mononuclear Cu(II) complexes, [Cu(L¹H₂)](ClO₄)_1.25Cl_0.75·1.25H₂O (1) and [Cu(L²H₂)](ClO₄)₂ (2), of the pyridoxal Schiff base ligands N,N′-dipyridoxylethylenediimine (L¹H₂) and N,N′-dipyridoxyl-1,3-propanediimine (L²H₂) are reported. X-ray crystal structures of both complexes are also reported. In both complexes the pyridoxal nitrogen atoms remain protonated. In the solid state, the tetradentate Schiff base ligand is virtually planar in 1, while in 2 the ligand conformation is like an inverted umbrella. In cyclic voltammetry experiments it is found that in these complexes the Cu(III) and Cu(I) states are more easily accessible than in their salen type analogs. The pyridoxal Schiff base complexes are also found to be resistant to oxidative electro-polymerization, unlike their corresponding salicyl aldehyde Schiff base complexes.     

Synthesis and characterization of copper(II) and cobalt(II) complexes with two new potentially hexadentate Schiff base ligands. X-ray crystal structure determination of one copper(II) complex

Two new potentially hexadentate N₂O₄ Schiff base ligands 2-((z)-(2-(2-(2-((z)-3,5-di-tert-butyl-2-hydroxybenzylideneamino) phenoxy) phenoxy) phenylimino) methyl)-4,6-di-tert-butylphenol [H₂L¹] and 2-((z)-(2-(2-(2-((z)-3,5-di-tert-butyl-2-hydroxybenzylideneamino) phenoxy)-5-tert-butylphenoxy) phenylimino) methyl)-4,6-di-tert-butylphenol [H₂L²] were prepared from the reaction of 3,5-di-tert-butyl-2-hydroxy benzaldehyde with 1,2-bis(2′-aminophenoxy)benzene or 1,2-bis(2′-aminophenoxy)-4-t-butylbenzene, respectively. From the direct reaction of ligands [H₂L¹] and [H₂L²] with copper(II) and cobalt(II) salts in methanolic solution and in the presence of N(Et)₃ the neutral [CuL¹], [CuL²], [CoL¹] and [CoL²] complexes were prepared. All complexes were characterized by IR spectra, elemental analysis, magnetic susceptibility, mass spectra, molar conductance (Λ_m), UV-Vis spectra and in the case of [CuL²] with X-ray diffraction. X-ray crystal structure of [CuL²] showed that the complex contains copper(II) in a distorted square planar environment of N₂O₂ donors. Three CH/π interactions were observed in the molecular structure of latter complex.     

Copper(II) complexes of schiff bases derived of 2-hydroxy-3-naphthaldehyde. The crystal and molecular structures of bis-{(phenyl)[(2-oxo-3H-naphth-3-ylidene)methyl]aminato}copper(II) and bis-{(benzene-4-trifluoromethyl)[(2-oxo-3H-naphth-3-ylidene)-methyl]aminato}copper(II)

Summary The Schiff base ligands, 3-[(Phenyl)-2-hydroxy-3H-Naphth-3-ylidene)methyl]aldamine (1) and 3-[(benzene-4-trifluoromethyl)-2-hydroxy-3H-naphth-3-ylidene)methyl]aldamine (2), and their corresponding Cu(II) complexes (I andII were synthesized. The crystal and molecular structures ofI andII were determined. CompoundI crystallizes in the triclinic crystal systema=10.804(5),b=12.589(5), andc=10.369(3) (Å), =107.72(3), =95.75(3), and =76.32(4)(°), in the space group P withZ=2. CompoundII crystallizes in the triclinic crystal systema=10.718(2),b=13.861(4), andc=10.110(9) (Å), =95.99(2), =90.16(2), and =93.90(2)(°), in the space group P withZ=2. The geometry around the metal atom in both complexesI andII is square planar.

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Kupfer(II)-Komplexe von Schiffbasen von 2-Hydroxy-3-naphthaldehyd. Die Kristall-und Molekülstrukturen von Bis{(phenyl)[(2-oxo-3H-naphth-3-yliden)methyl]aminato}kupfer(II) und Bis{(benzen-4-trifluoromethyl)[(2-oxo-3H-naphth-3-yliden)methyl]aminato}kupfer(II)

Zusammenfassung Es wurden die Schiffbasen-Liganden 3-[(Phenyl)-2-hydroxy-3H-naphth-3-yliden)-methyl]aldamin (1) und 3-[(Benzen-4-trifluoromethyl)-2-hydroxy-3H-naphth-3-yliden)-methyl]aldamin (2) inklusive der entsprechenden Kupfer(II)-KomplexeI undII dargestellt. VonI undII wurden die Kristallstrukturen ermittelt. KomplexI kristallisiert im triklinen System mita=10.804(5),b=12.589(5),c=10.369(3) Å, =107.72(3), =95.75(3) und =76.32(4)° in der Raumgruppe P mitZ=2. VerbindungII kristallisiert ebenfalls im triklinen System mita=10.718(2),b=13.861(4),c=10.110(9) Å, =95.99(2), =90.16(2) und =93.90(2)° in der Raumgruppe P mitZ=2. Die Geometrie rund um Cu ist in beiden Komplexen quadratisch-planar.

     

Synthesis,crystal structures and fluorescence properties of two new di- and polynuclear Cd(II) complexes with N2O donor set of a tridentate Schiff base ligand

Two new Cd(II) complexes, having one binuclear structure [Cd₂(L)₂(Cl)₂] (1) and another azido bridged one-dimensional zig-zag polynuclear network [Cd₃(μ_1,1-N₃)₄(L)₂{H₂N(CH₂)₂N(C₂H₅)₂} · H₂O]_n (2) have been synthesized from a tridentate N₂O donor Schiff base ligand LH, [LH = (OCH₃)(OH)C₆H₃CHN(CH₂)₂N(C₂H₅)₂], which is the condensation product of 2-hydroxy-4-methoxybenzaldehyde and 2-diethylaminoethylamine. Both the complexes 1 and 2 have been characterized by elemental analyses, IR & ¹H NMR spectroscopy, TGA and fluorescence studies. Finally their structures have been established by single crystal X-ray diffraction method. Structural study reveals that in the complex 1, two Cd(II) centers are held together by two μ₂-phenolato oxygen atoms and the terminal chlorine atom occupies the apical site of the square pyramidal environment of each metal center. In case of complex 2, the trinuclear asymmetric unit contains octahedral Cd(II) centers which are further held together by doubly end-on azido bridging to form a zig-zag polynuclear structure. It also displays intraligand ¹(π–π^∗) fluorescence and can potentially serve as photoactive material.     

Syntheses, crystal structures and electronic properties of a series of copper(II) complexes with 3,5-halogen-substituted Schiff base ligands and their solutions

We have systematically investigated the structural features, electronic properties, thermally-induced structural phase transitions and absorption spectra depending on the solvent for ten Cu(II) complexes with 3,5-halogen-substituted Schiff base ligands. Structural characterization of two new complexes, bis(N-R-1-phenylethyl- and N-R,S-2-butyl-5-bromosalicydenaminato-κ²N,O)copper(II), reveals that they afford a compressed tetrahedral trans-[CuN₂O₂] coordination geometry with trans-N–Cu–N = 159.4(2)° and trans-O–Cu–O = 151.7(3)° for the 1-phenylethyl complex and trans-N–Cu–N = 157.9(3)° and trans-O–Cu–O = 151.0(3)° for the 2-butyl one. All the complexes exhibit a structural phase transition by heating in the solid state regardless of their structures at room temperature. The absorption spectra of a series of ten complexes exhibit a slight shift of the d–d band at 16 000–20 000 cm⁻¹ and remarkable shift of the π–π* band at 24 000–28 000 cm⁻¹, which suggests that the dipole moment of the solvents presumably affects the conformation of the π-conjugated moieties of the ligands rather than the coordination environment. We have also attempted ‘photochromic solute-induced solvatochromism’ by a system of bis(N-R-1-phenylethyl-3,5-dichlorosalicydenaminato-κ²N,O)copper(II) and photochromic 4-hydroxyazobenzene in chloroform solution. We successfully observed a change of the d–d and π–π* bands of the complex in the absorption spectra caused by cis–trans photoisomerization of 4-hydroxyazobenzene.     

Spectrophotometric study of coproporphyrin-I complexes of copper(II) and cobalt(II)

The reagent 3,8,13,18-tetramethyl-21H,23H-porphine-2,7,12,17-tetrapropionic acid or coproporphyrin-I (CPI) was used for the spectrophotometric determination of copper(II) and cobalt(II) in the presence of pyridine and imidazole catalysts. Optimum conditions were investigated and the methods were applied to the determination of parts per billion levels of copper(II) and cobalt(II). The Sandell sensitivities of the recommended procedures were 0.568 μm cm⁻² and 0.464 μg cm⁻² (for A = 0.001) for copper and cobalt, respectively. The relative standard deviations were 2.0% for copper and 1.0% for cobalt. The kinetics of the reaction of CPI with copper(II) and cobalt(II) in the presence of the catalysts and the influence of the temperature were studied, and their kinetic constants determined.The influence of light on the photodecomposition of CPI was also studied.