Thiadiazoloporphyrinoids. Coordination of hexa(4-tert-butylphenyl)-substituted trithiadiazoltripyrrol macrocycle with Ni(II) in DMF

The rate constants, partial orders in the reagent concentrations and activation parameters of interaction of macroheterocyclic compound based on consecutively alternating fragments of thiazole and 3,4-bis(4-tert-butylphenyl)pyrole (3 + 3) with dehydrated Ni(OAc)₂ in dry DNF depending on the reagent concentrations and temperature were determined. Within a narrow range of the salt concentrations ((1.58?1.87) × 10^?4 mol/l), the third-order equation of the reaction rate was obtained i.e., the first order in a macrocyclic ligand and the second order in a salt, which was interpreted in terms of the mechanism of a stepwise coordination with three [Ni(OAc)]⁺ ions that is reversible only at the second step. Because of the low solubility of McH₃, the monomer-dimer equilibrium also becomes kinetically significant. The constant of McH₃ dimerization in DMF at 298 K equal to 1.6 × 10⁵ mol^?1 was determined by spectrophotometric titration.     

Ion-molecular interactions in the metalloporphyrin-acid system in liquid solutions

A new form of MP...H _solv ⁺ metalloporphyrins is found and studied in the strong acid medium, the conditions of its formation and the qualitative reaction of its determination are established. It is shown that the same form has the H₄TPP²⁺ dication (TPP is the 5,10,15,20-tetraphenyl-21H,23H-porphyrine dianion). The stability in different acid media and in the isolated state, spectral properties and the structure of H⁺-associates of porphyrins are analyzed in detail by UV-visible and ¹H NMR spectroscopy and quantum chemical calculations. It is shown that they have a unique two-band visible electronic spectrum with the bands near 540 nm and 700 nm, which weakly depend on the type of the central atom in the complex and noticeably change when the chromophore is functionally substituted. The proton location the ion-molecular associate and the cases of the formation of H⁺-associates with higher stoichiometry are revealed.     

The kinetics of complex formation in the trithiadiazoletri[3,4-di(4-tert-butylphenyl)-pyrrole] macrocycle-copper(II) acetate-DMFA-H2O system

The paper presents the results of a study of the kinetics of coordination of a macroheterocyclic compound with an increased coordination cavity of the (3 + 3) McH₃ composition consisting of sequentially alternating 1,3,4-thiadiazole and 3,4-bis(4-tert-butylphenyl)pyrrole fragments to dehydrated Cu(OAc)₂ in dimethylformamide with and without H₂O admixtures. The reaction could be controlled spectrophotometrically over the salt and ligand concentration ranges (0.175?0.55) × 10^?4 and (0.16?0.64) × 10^?5 mol/l, respectively, at temperatures of 288–303 K. A kinetic equation of an unusual form with a negative order with respect to the salt was for the first time obtained experimentally for a macrocyclic ligand by the method of excess concentrations. The kinetics of the complex formation reaction was given a theoretical interpretation. Quantitative characteristics were obtained, and the role played by water in the kinetics of complex formation was studied. These data were of importance for practical applications, for the development of optimum conditions increasing the yield of complexes when they were synthesized in complex formation reactions.     

Coordination of 5,10,15,20-tetraphenyl-21H,23H-porphin by rhenium in various oxidation states

A method was developed for the synthesis of three rhenium complexes, (5,10,15,20-tetraphenyl-21H,23H-porphinato)(phenoxo)rhenium(III) (PhO)ReTPP, (5,10,15,20-tetraphenyl-21H,23H-porphi-nato)(chloro)rhenium(III) (Cl)ReTPP, and μ-oxo-bis[(oxo)-(5,10,15,20-tetraphenyl-21H,23H-porphi-nato)rhenium(V)] [O=ReTPP]₂O, by one reaction between porphyrin H₂TPP and H₂ReCl₆ in boiling phenol. In the complex formation reaction accompanied by the redox process, only the metal cation is involved in the transformation. Rhenium(IV) as chlororhenic acid dispropoportionates without participation of solvent or porphyrin to give Re(III) and Re(V) complexes. The chemical structures of the products were established by spectral and elemental analysis. Characteristics of the UV, Vis, IR, and ¹H NMR spectra, the chromatographic mobility, and stability of the complexes were determined.     

Synthesis and Reactivity of Porphyrin Complexes of Group IV p-Elements

The composition of products and the general regularities of complex formation of meso-tetraphenylporphine with Si(IV), Ge(IV), Sn(II), and Pb(II), as well as the kinetics and mechanism of dissociation of the resulting complexes under the action of proton-donor reagents were studied. The nature of chemical and steric factors that operate to stabilize mixed-ligand acido porphyrin p-metal complexes was revealed.     

Thermodynamics of the equilibrium of the reaction between (5,10,15,20-tetra(2-methoxyphenyl)porphinato)chloroindium(III) and pyridine

The results from thermodynamic and quantum-chemical studies of the reversible reaction between (5,10,15,20-tetra(2-methoxyphenyl)porphinato)chloroindium(III) and pyridine are reported. The main physicochemical parameters of properties of its supramolecular products are obtained and analyzed. The addition of pyridine molecules to metalloporphyrin proceeds in one step to attain an equilibrium state with the formation of supramolecules with a stoichiometry of 2: 1; spectral characteristics and parameters of the stability of the latter are identified. The possibility of using substituted indium(III)porphyrin for further research in the field of hybrid solar cells is discussed.     

Study of complex formation between lead(II) acetate andmeso-tetraphenylporphin

The reaction of Pb(OAc)₂ withmeso-tetraphenylporphin in boiling pyridine orN,N-dimethylformamide gave complexes of Pb^II with tetraphenylchlorin or Pb^IV with tetraphenylporphin. The scheme of redox reactions occurring during the complex formation involving Pb²⁺ as the reducing agent was suggested. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2052–2055, October, 1998.