金属调控的2，4，6-三(2-吡啶基)-1，3，5-三嗪基配合物的光致变色性能

在溶剂热条件下,将2,4,6?三(2?吡啶基)?1,3,5?三嗪(2?TPT)、2,5?呋喃二羧酸(2,5?H₂FCA)分别与不同类型的金属硝酸盐(Zn、Cd和Mn)进行组装,得到了3个2?TPT基配合物:Zn(2?TPT)(2,5?FCA)](1)、Cd(2?TPT)(2,5?FCA)]·1.5H₂O(2)和Mn(2?TPT)(2,5?FCA)](3)。通过单晶X射线衍射、粉末X射线衍射、FT?IR、UV?Vis、差热-热重、电子顺磁共振和X射线光电子能谱对1~3的结构和光致变色性能进行了表征,并详细地探究了其光致变色机理。配合物1~3表现出明显差异的光诱导分子间电子转移和光致变色性能,主要体现在光响应速率和颜色对比度2个方面。其中,1的光致变色性能明显优于2,而3不具有光致变色行为。这种明显差异的光致变色行为,主要归因于不同类型的金属及其配位模式的差异所引起的不同晶体堆积模式和电子给体-受体间相对位置关系(界面关系),体现出了金属对于光致变色性能的调控作用。

Metal-Modulated Photochromic Properties of 2,4,6-Tri(2-pyridyl)-1,3,5-triazine Based Complexes

Three 2-TPT-based complexes composed of donor-acceptor units,Zn(2-TPT)(2,5-FCA)] (1),Cd(2-TPT) (2,5-FCA)]·1.5H₂O (2), andMn(2-TPT)(2,5-FCA)] (3), have been synthesized by the combination of 2,4,6-tri(2-pyridyl)-1,3,5-triazine (2-TPT) and 2,5-furandicarboxylic acid (2,5-H₂FCA) with different types of metallic nitrates (Zn, Cd, and Mn), respectively. The structures and photochromic properties of 1-3 have been characterized by single-crystal X-ray diffraction, powder X-ray diffraction, FT-IR, UV-Vis, thermogravimetry-differential thermal analysis, electron paramagnetic resonance and X-ray photoelectron spectroscopy. The usage of different metals leads to a 1D single-strand chain for 1 and a double-strand chain for 2 and 3, which are further aggregated into distinct supramolecular frameworks (three-dimensional supramolecular network for 1, two-dimensional supramolecular layer for 2, and discrete chain for 3) through weak interactions. Complexes 1-3 exhibited significantly different photoinduced intermolecular electron transfer (PIET) and photochromic properties, which were mainly reflect in photoresponsive rate and coloration contrast. Thereinto, the photochromic performance of 1 was obviously better than that of 2, while 3 was non-photochromic. These obviously discriminative photochromic behaviors are largely attributed to the different packing modes of crystal structures and the discriminative relative position of electron donors/acceptors caused by different types and coordination patterns of the metal centers, which exhibit the modulating effect of metal centers on the photochromic properties.