Binding of Catechols to Mononuclear Titanium(IV) and to 1- and 5-nm TiO2 Nanoparticles

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• 作者：Carol Creutz ; Mei H. Chou
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：May 5, 2008
• 年：2008
• 卷：47
• 期：9
• 页码：3509 - 3514
• 全文大小：582K
• 年卷期：v.47,no.9(May 5, 2008)
• ISSN：1520-510X

文摘

The binding of catechol derivatives (LH₂ = catechol, 4-methyl catechol, 4-t-butyl catechol, and dopamine) to 1- and 4.7-nm TiO₂ nanoparticles in aqueous, pH 3.5 suspensions has been characterized by UV−vis spectroscopy. The binding constants derived from Benesi−Hildebrand plots are (2−4) × 10³ M⁻¹ for the 1-nm nanoparticles and (0.4–1) × 10⁴ M⁻¹ for the 4.7-nm particles. Ti^IVL₃ complexes were prepared from the same catechols. The L = methyl catechol, and dopamine complexes are reported for the first time. The TiL₃ reduction potentials are not very sensitive to the nature of the catechol nor evidently are the binding constants to TiO₂ nanoparticles. The intense (ε ≥ 10³ M⁻¹ cm⁻¹), about 400-nm, ligand-to-metal charge-transfer (LMCT) absorptions of the nanoparticle complexes are compared with those of the TiL₃ complexes (ε ~ 10⁴ M⁻¹ cm⁻¹) which lie in the same spectral region. The nanoparticle colors are attributed (as are the colors of the Ti^IVL₃ complexes) to the tails of the about 400-nm LMCT bands.