Creutz Carol, Chou Mei H
Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
Inorg Chem. 2008 May 5;47(9):3509-14. doi: 10.1021/ic701687k. Epub 2008 Mar 27.
The binding of catechol derivatives (LH 2 = 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) x 10(3) M(-1) for the 1-nm nanoparticles and (0.4-1) x 10(4)M(-1) for the 4.7-nm particles. Ti(IV)L3 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 (epsilon > or = 10(3) M(-1)cm(-1)), about 400-nm, ligand-to-metal charge-transfer (LMCT) absorptions of the nanoparticle complexes are compared with those of the TiL 3 complexes (epsilon approximately 10(4)M(-1) cm(-1)) which lie in the same spectral region. The nanoparticle colors are attributed (as are the colors of the Ti(IV)L3 complexes) to the tails of the about 400-nm LMCT bands.
通过紫外可见光谱对儿茶酚衍生物（LH₂ = 儿茶酚、4 - 甲基儿茶酚、4 - 叔丁基儿茶酚和多巴胺）在pH为3.5的水悬浮液中与1纳米和4.7纳米二氧化钛纳米颗粒的结合进行了表征。从贝内西 - 希尔德布兰德图得出的结合常数，对于1纳米的纳米颗粒为(2 - 4)×10³ M⁻¹，对于4.7纳米的颗粒为(0.4 - 1)×10⁴ M⁻¹。由相同的儿茶酚制备了Ti(IV)L₃配合物。首次报道了L = 甲基儿茶酚和多巴胺的配合物。TiL₃的还原电位对儿茶酚的性质不太敏感，对二氧化钛纳米颗粒的结合常数显然也不敏感。将纳米颗粒配合物在约400纳米处强烈的（ε≥10³ M⁻¹cm⁻¹）配体到金属的电荷转移（LMCT）吸收与位于相同光谱区域的TiL₃配合物（ε约为10⁴ M⁻¹ cm⁻¹）的吸收进行了比较。纳米颗粒的颜色（与Ti(IV)L₃配合物的颜色一样）归因于约400纳米LMCT带的尾部。
