DFT and TDDFT calculations at the level of PBE0/6-31G(d)/6-31þG (d) were performed systematically on seven porphyrins with symmetrical mesosubstitutents. Our results show that the planarity of the free base porphyrin (BP) are affected by the introduction of substitutents at the meso-position of the ring. Geometrical studies show that the introduction of electron-withdrawing groups brings about in-plane deformation in the porphyrin ring, whereas the bulky substitutents make an out-of-plane deformation. However, FMO's diagram shows that electronwithdrawing groups alter the degeneracy of the HOMO and HOMO À1 orbtial. Up on introduction of substituents at the meso-position, the Q band FMOs transitions were the same as in the case of free BP; however, the oscillator strength is changed. Electron releasing substituted at the meso-position shows bathochromic shift in the Q band region. However, the intensity or the hyperchromic shift is higher for the electron withdrawing groups. Solvation studies show that Q bands are blue shifted and B bands are red shifted, whereas the intensity of the B bands was highly enhanced compared with the Q bands. These theoretical studies would be helpful in designing new porphyrins for the photodynamic therapy and dye-sensitized solar cell applications.

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Self-assembled monolayers (SAMs) of 1,5-pentanedithiol and 1,9-nonanedithiol on Au (111) surfaces were used to adsorb copper ions (Cu 2+ ) from an ethanolic solution of cupric chloride (CuCl 2 ) by chemical interaction of thiol groups and copper ions assembling multilayer structures. Ellipsometry, contact angle measurement and X-ray photoelectron spectroscopy (XPS) confirmed that the alkanedithiol molecules formed SAMs with only one-ended thiol groups attached to the gold surface, leaving the other-ended thiol groups free, which is supported by the molecular mechanics calculation. XPS and X-ray Auger electron spectroscopy (XAES) not only indicate that copper ions deposited onto SAMs from the solution by the chemical reaction of copper ions with ended free thiol groups of SAMs, but more importantly demonstrate that copper is present in the +1 oxidation state in the multilayer system. Atomic force microscopy (AFM) was used to observe SAMs and multilayer structures.

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