دانلود مقاله : DFT/TD-DFT studies on structural and spectroscopic properties of metalloporphyrin c

چکیده : 

Given their efficacy in photosynthesis, a series of metalloporphyrins were examined using density functional

theory (DFT) and time-dependent DFT. An experimentally known zinc porphyrin has been calculated

to evaluate performance of various functionals, basis sets, computational models of solvent effect

and solvent sorts. With an alternative approach, absorption spectra of complexes (MLx, , Cd and

Hg, –4) varying substituted porphyrin Lx and metal center were investigated. It was shown that

the strongest peak at about 400 nm for MLx was attributed to the intra-porphyrin p?p transition. Substitution

of benzoic acid at the b-position of porphyrin core allows an extra intense peak at 450 nm in ML3

and ML4, but ML2 with the meso-substituted benzoic acid only displays some very weak low-energy

absorptions. Additionally, we theoretically designed [Ru(NCS)2Lx]2 and expected their possession of

advantages of polypyridyl ruthenium and porphyrin-based sensitizers. The present study reveals that

the L4 complex, [Ru(NCS)2L4]2, exhibits extra intense absorption peaks at 500 and 582 nm, allowing

for its promising application in dye-sensitized solar cells (DSSCs).