Role played by the organometallic fragment on the first hyperpolarizability of ...

• Author(s): Mendes, Paulo J. ; Carvalho, A. J. Palace ; Ramalho, J.P. Prates
• Date: 2009
• Persistent ID: http://hdl.handle.net/10174/5325
• Origin: Repositório Científico da Universidade de Évora
• Subject(s): TD-DFT; Quadratic hyperpolarizability; Iron acetylide complexes
• Document Type: Article
• Language: English

Description

The static first hyperpolarizabilities (β) for a series of both substituted thiophene-acetylide ligands and the corresponding 5-monocyclopentadienyliron(II) complexes were determined by density functional theory (DFT) calculations. The effect on the hyperpolarizabilities by various donor and acceptor substituents in the thiophene-acetylide ligands was studied. The nature and role of the electronic excitation contributions to the first hyperpolarizability, using time-dependent DFT (TD-DFT) calculations, are rationalized in terms of the two-level model. Our calculations show that the organometallic fragment can form a very effective push-pull system in combination with electron-withdrawing substituents in the thiophene acetylide moiety, leading to enhanced static first hyperpolarizabilities. Also, an improvement of the magnitude of β is expected if solvation effects are taken into account.