Spectroscopic and computational studies on the coordination-driven self-assembly complexes (ZnL)2 and (NiL)2 [L= bis(2,4-dimethyldipyrrin-3-yl)methane].

FT-IR, FT-Raman and electronic absorption spectroscopies were utilized in conjunction with density functional theory (DFT) calculations to investigate the ground and excited states of self-assembled dinuclear dimeric helicates (ZnL)2 and (NiL)2 [L = bis(2,4-dimethyldipyrrin-3-yl)methane]. These studies afford a detailed description of the ground-state geometric and electronic structures of (ZnL)2 and (NiL)2 and provide a comparison with similar geometrical metal-porphyrins. The results demonstrate that enlarging the basis set used in the DFT calculations results in an obvious alteration of the calculated bond lengths but negligible alteration of the calculated bond angles.

Photophysical properties of diphenyl-2,3-dihydroxychlorin and diphenylchlorin.

The photophysical properties of 5,15-diphenyl-2,3-dihydroxychlorin (DPCOH) and 5,15-diphenyl-chlorin (DPC) in organic solution were studied. Absorption, fluorescence, triplet state and photobleaching experiments are reported. The ground states of both compounds show strong absorbance in red region (lambda = 638 nm, epsilon = 35,000 M(-1) cm(-1) and lambda = 645 nm, epsilon = 42,000 M(-1) cm(-1), respectively) and the singlet excited states show low fluorescence quantum yields of 0.