Tetrabenzoporphyrin and -mono-, - Cis -di- and tetrabenzotriazaporphyrin derivatives: Electrochemical and spectroscopic implications of meso CH Group replacement with nitrogen

Nonperipherally hexyl-substituted metal-free tetrabenzoporphyrin (2H-TBP, 1a) tetrabenzomonoazaporphyrin (2H-TBMAP, 2a), tetrabenzo-cis-diazaporphyrin (2H-TBDAP, 3a), tetrabenzotriazaporphyrin (2H-TBTAP, 4a), and phthalocyanine (2H-Pc, 5a), as well as their copper complexes (1b-5b), were synthesized. As the number of meso nitrogen atoms increases from zero to four, Îmax of the Q-band absorption peak becomes red-shifted by almost 100 nm, and extinction coefficients increased at least threefold. Simultaneously the blue-shifted Soret (UV) band substantially decreased in intensity. These changes were related to the relative electron-density of each macrocycle expressed as the group electronegativity sum of all meso N and CH atom groups, âχR. X-ray photoelectron spectroscopy differentiated between the three different types of macrocyclic nitrogen atoms (the Ninner, (NH)inner, and Nmeso) in the metal-free complexes. Binding energies of the Nmeso and Ninner,Cu atoms in copper chelates could not be resolved. Copper insertion lowered especially the cathodic redox potentials, while all four observed redox processes occurred at larger potentials as the number of meso nitrogens increased. Computational chemical methods using density functional theory confirmed 1b to exhibit a Cu(II) reduction prior to ring-based reductions, while for 2b, Cu(II) reduction is the first reductive step only if the nonperipheral substituents are hydrogen. When they are methyl groups, it is the second reduction process; when they are ethyl, propyl, or hexyl, it becomes the third reductive process. Spectro-electrochemical measurements showed redox processes were associated with a substantial change in intensity of at least two main absorbances (the Q and Soret bands) in the UV spectra of these compounds

Synthesis and phase behaviour of mesomorphic transition-metal complexes of alcoxydithiobenzoates

Reaction of 4-alkoxydithiobenzoates (n-odtb, where n refers to the number of carbon atoms in the alkoxy chain) with divalent salts of nickel, palladium and zinc leads to complexes of the formula [M(n-odtb)2] where M = Ni, Pd and [Zn2(n-odtb)4] which are mesomorphic. The shortest-chain homologues of the Ni and Pd complexes show a nematic phase while at longer chain lengths, an Sc phase is observed. Most homologues of the zinc complexes show a nematic phase with an Sc phase appearing only for the longest homologues. The gold(III) complexes [AuX 2(n-odtb)] are also mesomorphic and show the SA phase. Single-crystal X-ray structure determinations have been carried out for [Pd(8-odtb)2], [Zn2(4-odtb)4] and [Zn 2(8-odtb)4], showing the first to be planar and the last two dinuclear with pseudo five-co-ordinate zinc atoms

Regional Disparities in Per Capita Income in India: Convergence of Divergence

The paper looks at the latest evidence on what has been happening to regional disparities in per capita income (measured as gross state domestic product per capita) in India over the first decade of the twenty-first century (1999/2000 to 2010/2011) by estimating cross-section equations for unconditional and conditional beta (?) convergence and sigma (?) convergence across thirty-two regions (twenty-eight states and four union territories). There is no evidence of unconditional convergence, but weak evidence of conditional convergence controlling for population growth, credit growth, male literacy, the share of agriculture in state GDP, and state expenditure as a share of state GDP. Sigma divergence has increased continuously, except among the poorest states