COORDINATION OF AN AMINO ALCOHOLIC SCHIFF BASE LIGAND TOWARD THE ZINC(II) ION: SPECTRAL,STRUCTURAL, THEORETICAL,AND DOCKING STUDIES

Journal of Structural Chemistry - A new zinc(II) complex of 2-(((2-((2-hydroxyethyl)amino)ethyl)imino)methyl)phenol (L), [Zn(Lz)Br2] (1), is prepared and identified by elemental analysis, FTIR and...     

Bis-qtpy (qtpy = 2,2':6',2'':6'',2'"-quaterpyridine) metal complexes, [M(qtpy)(2)]2+

Reactions of perchlorates of iron(II), nickel(II), and zinc(II) with 2,2':6',2':6',2'"-quaterpyridine (qtpy) gave the first crystallographically established bis-qtpy metal complexes of formula [M(qtpy)(2)][ClO(4)](2) (M = Fe, Ni, Zn). Coordination of two terdentate quaterpyridines to the same center produces a distorted octahedron of six nitrogen atoms around the metal, leaving two pendant pyridyl groups, one for each quaterpyridine. For the diamagnetic zinc system, an NMR investigation has been carried out in order to establish the conditions to obtain the intermediate mono-qtpy complex, of formula [Zn(qtpy)(H(2)O)(2)][ClO(4)](2), which has also been crystallographically established. The corresponding hexafluorophosphate derivatives [M(qtpy)(2)][PF(6)](2) (M = Ni and Zn) were prepared in DMF at room temperature.     

Complexation of metal ions, including alkali-earth and lanthanide(III) ions, in aqueous solution by the ligand 2,2',6',2'-terpyridyl

Some metal-ion-complexing properties of the ligand 2,2',6',2'-terpyridyl (terpy) in aqueous solution are determined by following the π-π* transitions of 2 × 10(-5) M terpy by UV-visible spectroscopy. It is found that terpy forms precipitates when present as the neutral ligand above pH ～5, in the presence of electrolytes such as NaClO(4) or NaCl added to control the ionic strength, as evidenced by large light-scattering peaks. The protonation constants of terpy are thus determined at the ionic strength (μ) = 0 to avoid precipitation and found to be 4.32(3) and 3.27(3). The log K(1) values were determined for terpy with alkali-earth metal ions Mg(II), Ca(II), Sr(II), and Ba(II) and Ln(III) (Ln = lanthanide) ions La(III), Gd(III), and Lu(III) by titration of 2 × 10(-5) M free terpy at pH >5.0 with solutions of the metal ion. Log K(1)(terpy) was determined for Zn(II), Cd(II), and Pb(II) by following the competition between the metal ions and protons as a function of the pH. Complex formation for all of these metal ions was accompanied by marked sharpening of the broad π-π* transitions of free terpy, which was attributed to complex formation affecting ligand vibrations, which in the free ligand are coupled to the π-π* transitions and thus broaden them. It is shown that log K(1)(terpy) for a wide variety of metal ions correlates well with log K(1)(NH(3)) values for the metal ions. The latter include both experimental log K(1)(NH(3)) values and log K(1)(NH(3)) values predicted previously by density functional theory calculation. The structure of [Ni(terpy)(2)][Ni(CN)(4)]·CH(3)CH(2)OH·H(2)O (1) is reported as follows: triclinic, P1, a = 8.644(3) ?, b = 9.840(3) ?, c = 20.162(6) ?, α = 97.355(5)°, β = 97.100(5)°, γ = 98.606(5)°, V = 1663.8(9) ?(3), Z = 4, and final R = 0.0319. The two Ni-N bonds to the central N donors of the terpy ligands in 1 average 1.990(2) ?, while the four peripheral Ni-N bonds average 2.107(10) ?. This difference in the M-N bond length for terpy complexes is typical of the complexes of smaller metal ions, while for larger metal ions, the difference is reversed. The significance of the metal-ion size dependence of the selectivity of polypyridyl ligands, and the greater rigidity of ligands based on aromatic groups such as pyridyl groups, is discussed.     

Determination of silver,gold, palladium,and platinum on milligram scale: m-(mercaptoacetamido)phenol as gravimetric reagent

Summary A method for the gravimetric determination of milligram quantities of Ag(I), Au(III), Pd(II), and Pt(IV) is presented. It is based on precipitation of the respective chelates withm-(mercaptoacetamido)phenol. Procedures for the analysis of binary and ternary mixtures are described.

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Zusammenfassung Die gravimetrische Bestimmung von Milligrammengen Ag(I), Au(III), Pd(II) und Pt(IV) durch Fällung ihrer Chelate mit m-Merkaptoacetamidophenol wird vorgeschlagen. Arbeitsvorschriften für die Analyse binärer oder ternärer Gemische wurden angegeben.

     

Investigation of the electronic, photosubstitution, redox, and surface properties of new ruthenium(II)-containing amphiphiles

A series of pyridine- and phenol-based ruthenium(II)-containing amphiphiles with bidentate ligands of the following types are reported: [(L(PyI))Ru(II)(bpy)(2)](PF(6))(2) (1), [(L(PyA))Ru(II)(bpy)(2)](PF(6))(2) (2), [(L(PhBuI))Ru(II)(bpy)(2)](PF(6)) (3), and [(L(PhClI))Ru(II)(bpy)(2)](PF(6)) (4). Species 1 and 2 are obtained by treatment of [Ru(bpy)(2)Cl(2)] with the ligands L(PyI) (N-(pyridine-2-ylmethylene)octadecan-1-amine) and L(PyA) (N-(pyridine-2-ylmethyl)octadecan-1-amine). The imine species 3 and 4 are synthesized by reaction of [Ru(bpy)(2)(CF(3)SO(3))(2)] with the amine ligands HL(PhBuA) (2,4-di-tert-butyl-6-((octadecylamino)methyl)phenol), and HL(PhClA) (2,4-dichloro-6-((octadecylamino)methyl)phenol). Compounds 1-4 are characterized by means of electrospray ionization (ESI(+)) mass spectrometry, elemental analyses, as well as electrochemical methods, infrared and UV-visible absorption and emission spectroscopies. The cyclic voltammograms (CVs) of 1-2 are marked by two successive processes around -1.78 and -2.27 V versus Fc(+)/Fc attributed to bipyridine reduction. A further ligand-centered reductive process is seen for 1. The Ru(II)/Ru(III) couple appears at 0.93 V versus Fc(+)/Fc. The phenolato-containing 3 and 4 species present relatively lower reduction potentials and more reversible redox behavior, along with Ru(II/III) and phenolate/phenoxyl oxidations. The interpretation of observed redox behavior is supported by density functional theory (DFT) calculations. Complexes 1-4 are surface-active as characterized by compression isotherms and Brewster angle microscopy. Species 1 and 2 show collapse pressures of about 29-32 mN·m(-1), and are strong candidates for the formation of redox-responsive monolayer films.     

Synthesis,characterization, and antimicrobial activity of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with ferrocenyl Schiff bases containing a phenol moiety

Three ferrocenyl Schiff bases containing a phenol moiety have been formed by 1:1 molar condensation of acetylferrocene with 2‐aminophenol, 2‐amino‐5‐picoline or 2‐amino‐5‐chlorophenol. These ligands form 2:1 complexs with cobalt(II), copper(II), nickel(II), and zinc(II) ions. From the different spectral data, it was found that coordination of the ligands with the metal ions takes place via the azomethine nitrogen atoms and the deprotonated oxygen of the phenol groups. These ligands and their complexes have been characterized by IR, ¹H NMR, ¹³C NMR, UV–Vis spectra, and elemental analysis. The spectral data of the ligands and their complexes are discussed in connection with the structural changes due to complexation. The complexes prepared showed good antimicrobial activity against Escherichia coli, Bacillus subtilus, and Candida albicans. Copyright © 2004 John Wiley & Sons, Ltd.     

Inhibitory effects of 3,3',4,5'-tetrahydroxystilbene and 3,3',4,5'-tetrahydroxybibenzyl, the constituents of Cassia garrettiana on antigen-induced histamine release in vitro.

3,3',4,5'-Tetrahydroxystilbene (I) and 3,3',4,5'-tetrahydroxybibenzyl (II), isolated from the heartwood of Cassia garrettiana Craib (Leguminosae), showed inhibitory effects on antigen-induced histamine release from rat peritoneal mast cells in vitro. The inhibitory effect of I (IC50 = 30.2 microM) was much stronger than that of II (greater than 100 microM). Compound II, as well as I (IC50 = 7.3 microM) reported previously, also inhibited the histamine release from human peripheral basophils induced by anti-immunoglobulin E (IgE) in vitro, and its IC50-value was 68.0 microM. These results suggest that the trans-olefin structure in the molecule may be necessary for I to have an inhibitory effect on histamine release. Considering that disodium cromoglycate did not show any significant inhibitory effect on anti-IgE-induced histamine release from human basophils, the strong inhibitory effects of I in both tests are of considerable interest.     

Enhancing effect of pyrrolidone derivatives on transdermal penetration of phenolsulfonphthalein and indomethacin from aqueous vehicle

We investigated the enhancing effect of three alkyl-2-pyrrolidones on transdermal penetration of phenolsulfonphthalein (phenol red) and indomethacin from an aqueous vehicle by using an in vitro technique with excised rat skin. The enhancers included 1-methyl- (I), 1-hexyl- (II) and 1-lauryl-2-pyrrolidone (III). These derivatives effectively enhanced the penetration and skin accumulation of phenol red and indomethacin. Lipophilic enhancers such as II and III showed particularly high enhancing effects. The penetration profiles of phenol red and indomethacin showed a lag phase followed by a linear increase. Compounds II and III showed long lag times. The enhancer penetration was also determined. Compounds I and II showed a slight penetration. Compound III showed little penetration but high skin accumulation.     

Reversed-phase ion-pair partition liquid chromatography of chelates with 2-(3,5-dibromo-2-pyridylazo)-5-[N-ethyl-N-(3-sulphopropyl) amino] phenol and analogues

The ion-pair reversed-phase chromatography of some transition metal chelates with 2-(3,5-dibromo-2-pyridylazo)-5-[N-ethyl-N-(3-sulphopropyl)amino]phenol (3,5-diBr-PAESPAP) was studied. 3,5-DiBr-PAESPAP and its V(V), Cr(III), Fe(II), Co(III) and Ni(II) chelates were retained on and the copper (II), zinc(II) and cadmium(II) chelates dissociated in an ODS column using acetonitrile/water (37+63, v/v) (pH 7.0) containing 0.01 M acetate, 0.01 M 3-(N-morpholino)propanesulphonate buffer (pH 7.0) and 0.05 M Na⁺ as mobile phase. The chromatograms of 3,5-diBr-PAESPAP chelates were compared with those of the chelates with 2-(3,5-dibromo- 2-pyridylazo)-5-[N-(3-sulphopropyl)amino]phenol (3,5-diBr-PASPAP),2-(5-bromo-2- pyridylazo)-5-[N-(3-sulphopropyl)amino]phenol and 2-(5-bromo-2-pyridylazo)-5-[N-propyl-N- (3-sulphopropyl)amino] phenol. With 3,5-diBr-PAESPAP the Fe(II) and Ni(II) chelates were not resolved, but resolution was achieved with 3,5-diBr-PASPAP. The calibration graphs were linear over the ranges 2.0–10.0 ng (10-μl injection) of Fe, Ni and Co and for 20–100 ng (10-μl injection) for V with 3,5-diBr-PAESPAP and 3,5-diBr-PASPAP.     

Novel Ni(II) Mixed Ligand Complex Modified Electrode: Catalytic Effect on Anodic Oxidation of Phenol

Cyclic voltammetry, using graphite paste electrode (GPE) and chemically modified GPE with Ni(II) mixed ligand complex (MGPE), is described for sensing and detoxification of phenol. A novel mixed ligand complex of nickel with 1,4,8,11‐tetraaza cyclotetradecane (cyclam) and thiocyanate in the molar ratio of 1 : 2 : 5 is synthesized and characterized by spectroscopic and electrochemical studies. The Ni(II)‐cyclam‐thiocyanate complex behaves as a fast electron‐transfer mediator, as nickel ions exist in higher oxidation state of Ni(III) on applying a potential of 1.25 V (vs. Ag/AgCl), which catalyses the oxidation of the target species. The mixed ligand complex, when incorporated in the graphite paste electrode, is sensitive to detect phenol as low as 10 μg/L in solution. The catalytic effect of the Ni(II)‐cyclam‐thiocyanate complex enhanced many folds the oxidation of phenol compared to GPE. The technique has potential for sensing/monitoring and detoxification of phenol released in the ecosystem from polluting industries.     

Ligand substituent effect observed for ytterbocene 4'-cyano-2,2':6',2' '-terpyridine

A new N-heterocyclic complex of ytterbocene (Cp(2)Yb(II), Cp = C(5)Me(5)) has been prepared by the addition of 4'-cyano-2,2':6',2' '-terpyridine (tpyCN) to Cp(2)Yb(II)(OEt(2)) in toluene to give a dark blue species designated as Cp(2)Yb(tpyCN). The effect of the electron-withdrawing group (-CN) on the redox potentials of the charge-transfer form of this complex [in which an electron is transferred from the f(14) metal center to the lowest unoccupied (pi) molecular orbital of the tpyCN ligand to give a 4f(13)-pi(1) electronic configuration] has been quantified by cyclic voltammetry. The tpyCN ligand stabilizes this configuration by 60 mV more than that in the unsubstituted tpy ligand complex and by 110 mV more than that in the unsubstituted bpy ligand complex. Magnetic susceptibility measurements corroborate the enhanced stabilization of the 4f(13)-pi(1) configuration by the substituted terpyridyl ligand complex. Furthermore, the temperature dependence of the magnetic data is most consistent with a thermally induced valence tautomeric equilibrium between this paramagnetic 4f(13)-pi(1) form that dominates near room temperature and the diamagnetic 4f(14)-pi(0) form that dominates at low temperature. Differing coordination modes for the tpyCN ligand to the ytterbocene center have also been confirmed by isolation and X-ray crystallographic characterization of complexes binding through either the cyano nitrogen of tpyCN or the three terpyridyl nitrogen atoms of tpyCN.     

Mass spectra of some bivalent transition-metal ion chelates with pyridylazo phenols and naphthols

The mass spectra of 2- and 4-(2-pyridylazo)phenol, 2-(2-pyridylazo)-1- and 1-(2-pyridylazo)-2-naphthol and several chelates of these compounds with manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) are discussed. Comparisons are made with the results of solution studies of complex formation of the same chelates.     

Thermochemical determination of the structure of negative ions on the basis of data from resonance electron capture mass spectrometry. Phenol, its chlorinated derivatives and a thioanalogue

Appearance energies for [M - H](-) ions from phenol (I), 4-chlorophenol (II), pentachlorophenol (III) and pentachlorothiophenol (IV) were measured. The following thermochemical data were deduced from experiment: DeltaH(acid) values of 343.3, 335.7, 317.1 and 317.1 kcal mol(-1) for RH molecules (I, II, III, and IV, respectively) and electron affinities (EAs) of R(.) free radicals 2.55, 2.90, 3.79, and 3.65 eV, respectively. Our data for phenol (I) and 4-chlorophenol (II) demonstrate a higher stabilization of ArO(-) anions than was previously accepted. Using the enthalpic shift procedure for molecules and a series of isodesmic reactions for free radicals, earlier elaborated by the authors, a new Delta$bf H_bf fbf 0$ values for the following gas-phase species were obtained (kcal mol(-1)): C(6)Cl(5)Br (5.0), C(6)Cl(5)SH (8.5), p-ClC(6)H(4)C(.) (2. 0), C(6)Cl(5)C(.) (-15), C(6)Cl(5)S(.) (44). Copyright 2000 John Wiley & Sons, Ltd.     

Synthesis, characterization and properties of some divalent metal(II) complexes: their electrochemical, catalytic, thermal and antimicrobial activity studies

In this study, we synthesized the amine compound 2-(2-aminoethyliminomethyl)phenol (H(3)A) as the starting material, and then we prepared the polydentate Schiff base ligands from the reactions of the amine compound (H(3)A) with phtaldialdehyde (H(2)L), 4-methyl-2,6-di-formlyphenol (H(3)L(1)) and 4-t-butyl-2,6-di-formylphenol (H(3)L(2)) in the ethanol solution. Moreover, the complexes Cd(II), Cu(II), Co(II), Ni(II), Zn(II) and Sn(II) of the ligands H(2)L, H(3)L(1) and H(3)L(2) have been prepared. All compounds have been characterized by the analytical and spectroscopic methods. In addition, the magnetic susceptibility and molar conductance measurements have been made. The catalytic properties of the mono- and binuclear Co(II) and Cu(II) complexes have been studied on the 3,5-di-tert-butylcatechol (3,5-DTBC) and ascorbic acid (aa) as a substrate. The oxidative C-C coupling properties of the Co(II) and Cu(II) complexes have been investigated on the sterically hindered 2,6-di-tert-butylphenol (dtbp). The antimicrobial activity properties of the ligands and their mono- and binuclear complexes have been studied against the bacteria and fungi. The results have been compared to the antibacterial and fungi drugs. The TGA curves show that the decomposition takes place in three steps for all complexes. Electrochemical properties of the complexes Cu(II) and Ni(II) have been investigated for the first time in acetonitrile by cyclic voltammetry.     

Novel Michael addition products of bis(amino acidato)metal(II) complexes: synthesis, characterization, dye degradation, and oxidation properties

Michael addition reactions of bis(amino acidato)metal(II) complexes (metal = copper, nickel, zinc; amino acid = glycine, dl-alanine, l-alanine) with acrylonitrile have been carried out under various experimental conditions in the absence of a base, resulting in mono- and disubstituted products in high yield, including partially hydrolyzed products. A reaction mechanism for the Michael addition on the nitrogen atom of the coordinated amino acid moiety, replacing the amino hydrogen atom(s), is proposed. All of the products have been characterized by Fourier transform infrared spectroscopy, electron paramagnetic resonance spectra, and elemental and electrochemical analyses. The single-crystal structures of bis( N-cyanoethylglycinato)copper(II) monohydrate ( 1a), diaquabis( N-cyanoethylglycinato)nickel(II), aquabis( N, N-dicyanoethylglycinato)copper(II) ( 2a), and bis[( N-propionamido- N-cyanoethyl)glycinato]copper(II) dihydrate ( 4a) have been confirmed by X-ray diffraction techniques. The products 1a, 2a, 4a, and bis( N-propionamidoglycinato)copper(II) monohydrate ( 3a) have been used as catalysts for the degradation of a phenol red dye and mild oxidation of various organic substrates in the presence of hydrogen peroxide. The monosubstituted complexes have been found to catalyze the reactions to a greater extent than the disubstituted complexes.     

Kinetics of the alkylation of phenol with methanol over catalysts derived from hydrotalcite-like anionic clays

Vapor phase alkylation of phenol with methanol was carried out over catalysts derived from a series of hydrotalcite (HT)-like compounds of the form M(II)Al-HT; where M(II)=Mg, Mn, Co, Ni, Cu and Zn with M(II)/Al atomic ratios of2–5. The kinetic parameters such as rate constant (k), apparent activation energy (E_a) and Arrhenius frequency factor (A_o) for the disappearance of phenol were evaluated employing a power law equation assuming pseudo-first order kinetics. The kinetic parameters were found to be in good agreement with phenol conversion. The existence of the compensation effect between E_a and ln A_o was tested.     

Studies on Phenol Oxidation with H2O2 Catalyzed by Schiff Base Cobalt(II) Complexes in Micellar Solution

The two Schiff base cobalt(II) complexes, CoL¹ and CoL², were synthesized and characterized. The metallomicelle made up of the cobalt(II) complexes and surfactants (CTAB, LSS and Brij35), as mimic peroxidase metalloenzyme, were used in the catalytic oxidation of phenol by H₂O₂. The mechanism and a kinetic mathematic model of the phenol catalytic oxidation were studied. The acid effect of reaction system, structural effect of the complexes, and effect of temperature on the rate of the phenol oxidation catalyzed by the mimetic peroxidases have been discussed. The results showed that the schiff base cobalt(II) complexes and their metallomicelles as peroxidase mimics exhibit good catalytic activity and similar catalytic character to natural enzyme.     

Bifunctional charge transfer operated fluorescent probes with acceptor and donor receptors. 2. Bifunctional cation coordination behavior of biphenyl-type sensor molecules incorporating 2,2':6',2' '-terpyridine acceptors

Based on donor (D)-acceptor (A) biphenyl (b) type molecules, a family of fluorescent reporters with integrated acceptor receptors and noncoordinating and coordinating donor substituents of varying strength has been designed for ratiometric emission sensing and multimodal signaling of metal ions and protons. In part 2 of this series on such charge transfer (CT) operated mono- and bifunctional fluorescent devices, the cation coordination behavior of the sensor molecules bpb-R equipped with a proton- and cation-responsive 2,2':6',2' '-terpyridine (bp) acceptor and either amino-type donor receptors (R = DMA, A15C5 = monoaza-15-crown-5) or nonbinding substituents (R = CF(3), H, OMe) is investigated employing the representative metal ions Na(I), Ca(II), Zn(II), Hg(II), and Cu(II) and steady-state and time-resolved fluorometry. The bpb-R molecules, the spectroscopic behavior and protonation behavior of which have been detailed in part 1 of this series, present rare examples for CT-operated bifunctional fluorescent probes that can undergo consecutive and/or simultaneous analyte recognition. The analyte-mediated change of the probes' intramolecular CT processes yields complexation site- and analyte-specific outputs, i.e., absorption and fluorescence modulations in energy, intensity, and lifetime. As revealed by the photophysical studies of the cation complexes of these fluoroionophores and the comparison to other neutral and charged D-A biphenyls, the spectroscopic properties of the acceptor chelates of bpb-R and A- and D-coordinated bpb-R are governed by CT control of an excited-state barrier toward formation of a forbidden charge transfer state, by the switching between analytically favorable anti-energy and common energy gap law type behavior, and by the electronic nature of the ligated metal ion. This accounts for the astonishingly high fluorescence quantum yields of the acceptor chelates of bpb-R equipped with weak or medium-sized donors and the red emission of D- and A-coordinated bpb-R observed for nonquenching metal ions.     

Stepwise synthesis of [Ru(trpy)(L)(X)](n+) (trpy = 2,2':6',2' '-terpyridine; L = 2,2'-dipyridylamine; X = Cl-, H2O, NO2-, NO+, O2-). Crystal structure, spectral, electron-transfer, and photophysical aspects

Ruthenium-terpyridine complexes incorporating a 2,2'-dipyridylamine ancillary ligand [Ru(II)(trpy)(L)(X)](ClO(4))(n) [trpy = 2,2':6',2' '-terpyridine; L = 2,2'-dipyridylamine; and X = Cl(-), n = 1 (1); X = H(2)O, n = 2 (2); X = NO(2)(-), n = 1 (3); X = NO(+), n = 3 (4)] were synthesized in a stepwise manner starting from Ru(III)(trpy)(Cl)(3). The single-crystal X-ray structures of all of the four members (1-4) were determined. The Ru(III)/Ru(II) couple of 1 and 3 appeared at 0.64 and 0.88 V versus the saturated calomel electrode in acetonitrile. The aqua complex 2 exhibited a metal-based couple at 0.48 V in water, and the potential increased linearly with the decrease in pH. The electron-proton content of the redox process over the pH range of 6.8-1.0 was calculated to be a 2e(-)/1H(+) process. However, the chemical oxidation of 2 by an aq Ce(IV) solution in 1 N H(2)SO(4) led to the direct formation of corresponding oxo species [Ru(IV)(trpy)(L)(O)](2+) via the concerted 2e(-)/2H(+) oxidation process. The two successive reductions of the coordinated nitrosyl function of 4 appeared at +0.34 and -0.34 V corresponding to Ru(II)-NO(+) --> Ru(II)-NO* and Ru(II)-NO* --> Ru(II)-NO(-), respectively. The one-electron-reduced Ru(II)-NO* species exhibited a free-radical electron paramagnetic resonance signal at g = 1.990 with nitrogen hyperfine structures at 77 K. The NO stretching frequency of 4 (1945 cm(-1)) was shifted to 1830 cm(-1) in the case of [Ru(II)(trpy)(L)(NO*)](2+). In aqueous solution, the nitrosyl complex 4 slowly transformed to the nitro derivative 3 with the pseudo-first-order rate constant of k(298)/s(-1) = 1.7 x 10(-4). The chloro complex 1 exhibited a dual luminescence at 650 and 715 nm with excited-state lifetimes of 6 and 1 micros, respectively.     

Synthesis and Spectral Properties of Ni(II), Pd(II), Pt(II), and Pt(IV) Tetraphenyltetrabenzoporphyrinates

Complexation reactions of 5,10,15,20-tetraphenyltetrabenzoporphyrin and transmetallation of its cadmium complex with nickel(II) acetate, Ni(II), Pd(II), and Pt(II) chlorides in dimethylformamide and phenol have been studied. The corresponding Ni(II), Pd(II), and Pt(II) porphyrinates have been synthesized. Pt^IVBr₂ porphyrinate has been obtained by the treatment of Pt(II) 5,10,15,20-tetraphenyltetrabenzoporphyrinate with bromine in chloroform. The obtained compounds have been characterized by elemental analysis, electronic absorption and ¹H NMR spectroscopy and mass spectrometry.