Key Lab for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
Department of Chemistry, Capital Normal University, Beijing 100048, China.
Dalton Trans. 2022 Mar 1;51(9):3706-3712. doi: 10.1039/d1dt04170c.
Six titanium-oxide clusters (TOCs) comprised of 6-19 Ti atoms all of which are of nanometer size were synthesized with the functionalization of 2-picolinate (PA). Their structures were determined by single-crystal X-ray diffraction and a few complementary spectroscopic techniques. The binding modes of PA on the surface of the TOCs were analyzed and found to be limited to only one binding mode, that is, PA acts as a bidentate ligand through both pyridyl-N and the carboxylate-O. UV-vis diffuse reflection spectra and electron paramagnetic resonance spectra indicate the ligand-to-metal charge transfer (LMCT) through the N-Ti bond. However, the LMCT band in the visible light region (400-600 nm) is very weak. Hence, picolinates do not bring about intense visible light absorption to TOCs. The binding mode of PA on the TOC surfaces and the LMCT revealed herein may be inspiring for studies on classical picolinate/TiO-based dye-sensitized solar cells.
六个由 6-19 个钛原子组成的二氧化钛簇（TOCs）均具有纳米级尺寸，并用 2-吡啶甲酸（PA）进行了功能化。通过单晶 X 射线衍射和一些补充的光谱技术确定了它们的结构。分析了 PA 在 TOC 表面的结合模式，发现其仅限于一种结合模式，即 PA 通过吡啶-N 和羧酸盐-O 作为双齿配体。紫外可见漫反射光谱和电子顺磁共振光谱表明通过 N-Ti 键发生配体到金属电荷转移（LMCT）。然而，可见光区域（400-600nm）的 LMCT 带非常弱。因此，吡啶甲酸酯不会使 TOCs 产生强烈的可见光吸收。本文揭示的 PA 在 TOC 表面的结合模式和 LMCT 可能为经典的吡啶甲酸酯/TiO 基染料敏化太阳能电池的研究提供启示。
