Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5416503 | Journal of Molecular Structure: THEOCHEM | 2010 | 9 Pages |
Abstract
The structure and stability of a series of porphyrin-nanotube complexes (ZnP-SWNT, H2P-SWNT, ZnP-pp-SWNT and H2P-pp-SWNT) were computed at the density functional theory (DFT) level. In addition, the first hyperpolarizability (β) was calculated using a coupled-perturbed-HF approach. The results indicate that complex stability is mainly dictated by the presence of Zn(II), with push-pull substituents also improving the stability. By taking the average interaction energy throughout the series of isomers found on the PES, the following stability order was predicted: ZnP-pp-SWNT > ZnP-SWNT â¼Â H2P-pp-SWNT > H2P-SWNT. In addition, the push-pull groups, namely NH2 and NO2 in the present work, are essential to the first hyperpolarizability enhancement. For the free porphyrins ZnP-pp and H2P-pp, the β values were (in 10â30 esuâ1 cm5) 55 and 68, respectively. These values rose to 93 and 121 (increasing by around 40%) when the complexes with SWNT were formed. Thus, these results indicate that the hybrid nanocomposites represented by H2P-pp-SWNT and ZnP-pp-SWNT might be interesting systems to investigate as lead compounds for NLO properties.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Leonardo A. De Souza, Antônio M. Da Jr., Geórgia M.A. Junqueira, Ana Cláudia M. Carvalho, Hélio F. Dos Santos,