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Title hybrid iron(II)- and cobalt(III)-centered complexes were prepared in moderate yields using the template reactions of 3-acetylpyrazoloxime as a chelating ligand synthon with a Lewis-acidic zirconium or hafnium(IV) phthalocyaninate on the corresponding 3d-metal ion as a matrix. Formation of the cobalt(III)-centered complexes is observed due to the oxidation of Co2+ cations of the initial cobalt(II) salt. Thus obtained binuclear chloride H-bonded iron(II) and cobalt(III) compounds were characterized using elemental analysis, 1H and 13C {1H} NMR, MALDI-TOF mass, 57Fe Mössbauer (for iron compounds) and UV-vis spectra, and by single-crystal X-ray diffraction (XRD). Their redox properties were studied by cyclic (CV) and differential pulse voltammetry methods, and using spectroelectrochemical experiments. Their encapsulated 3d-metal ions with the electronic d6 configuration are located almost in the center of MN6-coordination polyhedra, the geometry of which is more closer to a trigonal antiprism (TAP, the distortion angle ϕ = 60°) than to a trigonal prism (TP, ϕ = 0°) with ϕ ∼ 40°. FeII–N distances fall in the range 1.913(6)–1.965(7) Å, while the CoIII–N bond lengths are from 1.890(8) to 1.935(8) Å. The geometry of MIVO3N4-coordination polyhedra of their capping metal(IV) ions is intermediate between a capped TAP and a capped TP. In the molecules of ZrIVMIIIMIIMIIZrIV-pentanuclear intracomplexes, (HS)FeIII–N and (LS)CoIII–N distances in their two semiclathrochelate fragments fall in the ranges 1.915(10)–1.980(12) Å and 1.886(13)–1.930(13) Å, respectively, and the geometry of MN6-coordination polyhedra is closer to a TAP (values of ϕ are higher than 30°). The geometry of MN6-polyhedra of the HS cross-linking metal(II) ions between them is close to a TAP (values of ϕ are higher than 50°). All the obtained binuclear hybrid complexes exhibit very similar electrochemical patterns. Their CVs contain quasi-reversible or irreversible three reduction and three oxidation waves. The potentials of electrochemical reductions, assigned to the Pc-localized redox processes, are close to each other. The first of them is a quasi-reversible process attributed to the Pc-based one-electron reduction, while the first oxidation wave was assigned to the metal-centered M2+/3+ redox couples. The spectroelectrochemical data confirmed an assignment of the aforementioned electrochemical processes. [ABSTRACT FROM AUTHOR]

Combined experimental 57Fe Mössbauer and theoretical DFT study of a series of iron(II)-centered (pseudo)macrobicyclic analogs and homologs was performed. The field strength of the corresponding (pseudo)encapsulating ligand was found to affect both the spin state of a caged iron(II) ion and the electron density at its nucleus. In a row of the iron(II) tris-dioximates, passing from the non-macrocyclic complex to its monocapped pseudomacrobicyclic analog caused an increase both in the ligand field strength and in the electron density at the Fe2+ ion, and, therefore, a decrease in the isomer shift (IS) value (so-called "semiclathrochelate effect"). Its macrobicyclization, giving the quasiaromatic cage complex, caused a further increase in the two former parameters and a decrease in IS (so-called "macrobicyclic effect"). The trend of their IS values was successfully predicted using the performed quantum-chemical calculations and the corresponding linear correlation with the electron density at their 57Fe nuclei was plotted. A variety of different functionals can be successfully used for such excellent prediction. The slope of this correlation was found to be unaffected by the used functional. In contrast, the predictions of both the sign and the values of quadrupole splitting (QS) for them, based on the theoretical calculations of EFG tensors, were found to be a real great challenge, which could not be solved at the moment even in the case of these C3-pseudosymmetric iron(II) complexes with known XRD structures. The latter experimental data allowed us to deduce a sign of the QSs for them. The straightforwarded molecular design of a (pseudo)encapsulating ligand is proposed to control both the spin state and the redox characteristics of an encapsulated metal ion. [ABSTRACT FROM AUTHOR]

An optical fluorescent sensor based on a chitosan thin film co-doped with Eu3+ and a bromothymol blue pH indicator has been developed. Near-UV to visible (350-400 nm) excitation of the europium (III) chelate complexes with 1,3-diphenyl-1,3-propanedione exhibits a typical lanthanide emission with maximum at 618 nm. Luminescent spectra of the Eu3+ complex were found to be insensitive to the presence of methylamine gas. Therefore, bromothymol blue, a non-fluorescent pH indicator with an absorbance maximum of deprotonated form close to the Eu3+ emission band was added to the film to provide a non-fluorescent reversible response to different methylamine concentrations, which can be detected by measuring the Eu3+ emission. [ABSTRACT FROM AUTHOR]

Here we report on synthesis of new organic-inorganic materials based on products of interaction between sodium aminoprusside and polymer ligands. Fourier transform infrared (FT-IR) and UV-visible spectroscopy and thermogravimetry were used to investigate the structure and stability of the complexes. It was found that ion and ligand exchange were the main reactions of the interaction of sodium aminoprusside with water-soluble polymer salts. All other composites in the Co(II) form were characterized in terms of sorption capacities and distribution coefficients (Kd) for cesium ions. The highest values of distribution coefficients were obtained for polyampholyte chitosan derivatives. [ABSTRACT FROM AUTHOR]

Combined experimental 57 Fe Mössbauer and theoretical DFT study of a series of iron(II)-centered (pseudo)macrobicyclic analogs and homologs was performed. The field strength of the corresponding (pseudo)encapsulating ligand was found to affect both the spin state of a caged iron(II) ion and the electron density at its nucleus. In a row of the iron(II) tris-dioximates, passing from the non-macrocyclic complex to its monocapped pseudomacrobicyclic analog caused an increase both in the ligand field strength and in the electron density at the Fe 2+ ion, and, therefore, a decrease in the isomer shift (IS) value (so-called "semiclathrochelate effect"). Its macrobicyclization, giving the quasiaromatic cage complex, caused a further increase in the two former parameters and a decrease in IS (so-called "macrobicyclic effect"). The trend of their IS values was successfully predicted using the performed quantum-chemical calculations and the corresponding linear correlation with the electron density at their 57 Fe nuclei was plotted. A variety of different functionals can be successfully used for such excellent prediction. The slope of this correlation was found to be unaffected by the used functional. In contrast, the predictions of both the sign and the values of quadrupole splitting (QS) for them, based on the theoretical calculations of EFG tensors, were found to be a real great challenge, which could not be solved at the moment even in the case of these C 3 -pseudosymmetric iron(II) complexes with known XRD structures. The latter experimental data allowed us to deduce a sign of the QSs for them. The straightforwarded molecular design of a (pseudo)encapsulating ligand is proposed to control both the spin state and the redox characteristics of an encapsulated metal ion.