Narrow Results

The synthesis of metallo derivatives (Ni, Zn) of phthalocyanines (pcs) obtained from 4,5-dicyanobenzomonoazacrown ether substituted with long alkyl chains (5a-d) are described. The new compounds have been characterized by elemental analysis, ¹H, ¹³C NMR, MS, IR and UV-vis spectroscopy techniques. The aggregation properties and alkali metal interaction of the pcs (6a-d and 7a-d) were investigated.

A new family of pyrrole substituted metallophthalocyanine complexes, namely cobalt(II), iron(II), manganese(III), nickel(II) and zinc(II) tetrakis-4-(pyrrol-1-yl)phenoxy phthalocyanines (noted as M(TPhPyrPc), where M is the metallic cation) have been synthesized and fully characterized. In particular, the UV-visible spectra of the iron and nickel complexes showed extensive aggregation even at low concentrations. The cyclic voltammetry of the cobalt, iron and manganese complexes showed three to four redox couples assigned to metal and ring based processes. Spectroelectrochemistry of the manganese derivative confirmed that the synthesized complex is Mn^III(TPhPyrPc^-2) and that the reduction of Mn^II(TPhPyrPc^-2) to be centred on the ring and rather than on the metal, forming the Mn^II(TPhPyrPc^-4) species. Also, the electrochemical polymerization of these newly synthesized pyrrole-substituted phthalocyanines has been demonstrated in the case of the cobalt complex and the electrocatalytic activity of the obtained film has been tested towards the oxidation of L-cysteine.

The (bpy)₂Ru^II and (phen)₂Ru^II moieties were linked to [Ni(OBTTAP)]1, periphery through coordinate bonds in order to synthesize cationic di- and pentanuclear complexes 2-5 that were obtained as PF₆⁻ salts. They were characterized by IR, ¹H NMR, UV-vis, and mass spectral data. The electronic absorption, emission and redox data of these bichromophoric systems indicate the presence of a high degree of intercomponent electronic interaction. The position and relative intensities of the Soret and Q bands in these complexes is altered due to peripheral binding of the metal units. The compounds were non-emissive for the Q band excitation but, Soret excitation led to a strong S₂ emission, observed between 400-450 nm. In cyclic voltammetry, the compounds exhibited one Ru centered oxidation together with one or two OBTTAP centered oxidations. The Ru^II/Ru^III oxidations were observed at significantly lower potentials as compared to the corresponding simple maleonitrile-benzylthioether complexes and has been interpretted in terms of weaker dπ(S)–dπ(Ru) interactions.

We report here the preparation (in "one-pot") of a tetra-β″-sulfoleno-meso-aryl-porphyrin in about 80% yield by using an optimized modification of Lindsey's variant of the Adler–Longo approach. The Zn(II)-, Cu(II)- and Ni(II)-complexes of the symmetrical porphyrin were prepared and characterized spectroscopically. Crystal structures of the fluorescent Zn(II)- and of the non-fluorescent Ni(II)-tetra-β″-sulfoleno-meso-aryl-porphyrinates showed the highly substituted porphyrin ligands to be nearly perfectly planar. The Zn(II)-complex of this porphyrin has been used as a thermal precursor of a reactive diene, and — formally — of lateral and diagonal bis-dienes, of a tris-diene and of a tetra-diene, which all underwent [4 + 2]-cycloaddition reactions in situ with a range of dienophiles. Thus, the tetra-β″-sulfoleno-meso-aryl-porphyrin and its metal complexes represent reactive building blocks, "programmed" for the syntheses of symmetrical and highly functionalized porphyrins.

By using quantum chemical calculation data obtained by the DFT method with the OPBE/TZVP and B3PW91/TZVP levels, the principal possibility of the existence of three heteroligand complexes of nickel, each of which was shown to contain in the inner coordination sphere either porphyrazine or di[benzo]- and tetra[benzo]porphyrazine, oxygen (O${}^{2-})$ and fluorine (F${}^{-})$ ions. The data on the geometric parameters of the molecular structure of these complexes are presented; which shows that NiN₄ chelate nodes, all metal-chelate and non-chelate cycles in each of these complexes, are strictly planar. The bond angles between two donor nitrogen atoms and a nickel atom are equal to 90${}^{\circ }$, while the bond angles between donor atoms N, Ni, and O or F, in most cases, albeit insignificantly, differ from this value. Nevertheless, the bond angles formed by Ni, O and F atoms are exactly 180${}^{\circ }$. NBO analysis data for these complexes are presented; it was noted that the ground state of all these complexes was a spin doublet. It has been shown that a good agreement between the data obtained using the above two versions of the DFT method occurs. Also, standard thermodynamic parameters of formation (standard enthalpy $\mathrm{\Delta }{H}_{f,298}^0$, entropy $S_{f,298}^0$ and Gibbs’s energy $\mathrm{\Delta }{G}_{f,298}^0)$ for the macrocyclic compounds under consideration were calculated.