The trends of kinetic resistance of borofluoride complexes of alkyl- and sulfo-substituted dipyrrolylmethene (Bodipy) to protolytic and solvoprotolytic dissociation in organic solvents and aqueous solutions are studied. It is established that among dipyrrolylmethene complexes with d elements, Bodipy is notable for its superresistance to acids. The rate of the dissociation reaction increases with increasing acidity of protonating mixtures or decreasing effective charge of the coordinating nitrogen atoms of the ligand. Dissociation of the complexes occurs in accordance with a second-order rate equation. A kinetic model of the process is proposed; its kinetic and activation parameters are determined. The energy profiles of the initial stages of protolytic dissociation reactions are calculated using quantum-chemical methods for two suggested variants of the transient state; the energetically preferable pathway is recognized.

Изучены закономерности кинетической устойчивости борфторидных комплексов алкил- и сульфозамещенных дипирролилметена (Bodipy) к протолитической и сольвопротолитической диссоциации в органических растворителях и водных растворах. Установлено, что по сравнению с комплексами дипирролилметенов с d-элементами Bodipy отличаются сверхустойчивостью к действию кислот. Скорость реакции диссоциации увеличивается с ростом кислотности протонирующих смесей и уменьшением эффективного заряда на координирующих атомах азота лиганда. Диссоциация комплексов протекает в соответствии с кинетическим уравнением второго порядка, предложена кинетическая модель процесса, определены его кинетические и активационные параметры. С использованием квантово-химических методов рассчитаны энергетические профили начальных стадий реакций протолитической диссоциации для двух вариантов предполагаемых переходных состояний и выявлен энергетически более предпочтительный маршрут.

Thermal effects of the reactions of complex formation between d- and f-elements and 3,3′,5,5′-tetramethyl-4,4′-diethyl-2,2′-dipyrrolylmethene in dimethylformamide are determined from data of titration microcalorimetry and the temperature behavior of the complex formation equilibrium constants. The entropy and free energy changes of the complex formation reactions are calculated. It is shown that enthalpy-entropy compensation is observed for complex formation processes in all cases. Contributions from the enthalpy and entropy factors to the free energy change of the complex formation are analyzed, allowing us to confirm earlier conclusions as to the effect of the nature of a complexing agent on the relative percentage of covalent and ionic characters of the M-L bond. The dependence of the complex formation enthalpies on the inverse radius of a complexing agent is revealed for the lanthanide complexes.

The formation kinetics of heteroligand Ni(II) complexes with alkylated dipyrrolylmethenes of symmetric and asymmetric structure was studied. The kinetic and activation parameters of the reactions were determined. The spectral and kinetic data obtained, as well as available data on the solvation of Ni(II) acetate in electron-donor solvents, allowed us to propose an associatively activated concerted mechanism. The Ni( II) complex formation is mainly determined by the rate of substitution of the entering ligand for solvent molecules in the initial Ni( II) complex, that is, by creation of conditions for efficient donor-acceptor interaction.

Intermediate products of synthesis of the boron trifluoride complexes with linear oligopyrroles are found. By means of electronic spectroscopy it was shown that the reaction of linear oligopyrroles with boron trifluoride in solutions resulted in the formation of stable donor-acceptor complexes. Their composition was established and the formation constants were evaluated. It was shown that transformation of these complexes in the corresponding borofluoride complexes is possible only while boiling the reaction mixture. By means of quantum-chemical methods the structural and energy parameters of the donor-acceptor complexes under study were calculated.

The reactions of symmetric and nonsymmetric alkyl-substituted 2,2′-dipyrrolylmethenes with Cu(II), Ni(II), Co(II), Zn(II), Cd(II), and Hg(II) acetates in dimethylformamide solutions at 298.15 K were studied. The formation of hetero- and homoligand complexes was observed in the systems studied depending on the concentration conditions and the nature of the complexing metal. The stepped and complete constants of formation for metal complexes were determined. The key trends of the influence of the metal and ligand nature on the stabilization of the complexes were established.

Results are reported on spectral investigation of alkylated dipyrrolylmethenes hydrohalides in organic solvents of various nature. The pigments were shown to exist in the concentrated solutions in benzene, chloroform, and dimethyl sulfoxide predominantly as associates, and in dilute solutions, as molecular salts. In dimethylformamide alongside an associated and protonated forms a nonprotonated form of dipyrrolylmethenes was present originating from the solvolytic dissociation of salts. The principal structural and solvation factors are considered governing the spectral characteristics and the stability of chemical forms of dipyrrolylmethenes.