Synthesis, structure and photophysical properties of 2-benzhydryl-4-methyl-6-(aryliminomethyl)phenol ligands and the zinc complexes thereof
摘要:
The Schiff-base ligands 2-benzhydryl-4-methyl-6-((phenylimino)methyl) phenol (L1-L5), and their corresponding zinc complexes (C1-C5), were prepared and fully characterized. The UV-Vis absorption and fluorescence spectra of the ligands and their Zn(II) complexes were measured in solvents such as methanol, dichloromethane, THF, or toluene, respectively. The results showed that the fluorescence intensity of the ligands was very weak, but upon coordination with Zn2+, the fluorescence intensity was greatly enhanced, and the fluorescent quantum yield ratio of C5 (0.46) to L5 (0.0004) in methanol increased by around 1150 times. The enhanced fluorescence of the zinc complexes is due to the intramolecular charge transfer (ICT) and the stronger geometrical rigidity of the delocalized bonding planes in these molecules. Transient absorption spectrum bands with peaks at about 310 and 460 nm were attributed to triplet state absorptions and absorption dynamic curve fitting showed that lifetimes were of microsecond level scale. There was no time-resolved property observed for the bleaching spectral bands at 350 nm and at ca. 460 nm. This spectral property, like the Stokes shift, can be attributed to the typical behavior of nanosecond transient absorption of the compounds with the excited-state intramolecular proton transfer (ESIPT). (C) 2012 Elsevier B. V. All rights reserved.
通过TiCl 4(THF)2与衍生自带有大体积苯甲酰基的配体(L1 - L6)的6-烷基-2-铝二氨基酚盐的钾盐的化学计量反应,合成了一系列三氯钛2-铝二氨基苯氧基化物配合物(C1 - C6)取代基,而在配体L6与0.5当量的TiCl 4(THF)2的反应中分离出双(2-二氨基苯氧基)钛二氯化物(C7)。所有钛配合物的特征是1 H / 1313 C NMR光谱和元素分析。单晶X射线衍射揭示了配合物C2,C4和C7的钛中心周围的八面体几何形状失真。经助催化剂MAO活化后,所有钛预催化剂在70°C的乙烯聚合反应中均表现出良好至高的活性(至多1.3×10 6 g mol(Ti)-1 h -1),从而生产出具有高活性的聚乙烯产品。分子量。此外,以10 5 g mol(Ti)-1 h -1的活性实现了乙烯与α-烯烃或降冰片烯的共聚。 通过这些钛预催化剂与共聚单体的良好结合,对于1-己烯通常分别为4
The stoichiometric reaction of the salicylaldimine derivatives (L1–L12) with trimethylaluminium afforded the corresponding dimethylaluminium aldiminophenolates (C1–C12), which were fully characterized by NMR spectroscopy and elemental analysis. The molecular structures of the representative complexes C1, C6, and C8 were determined by the single-crystal X-ray diffraction, which revealed distorted tetrahedral geometry at aluminium. Activation of the dimethylaluminium aldiminophenolates for the ring-opening polymerization required one equivalent of BnOH. On the basis of the polymerization results for L-lactide, D-lactide or rac-lactide, higher efficiency was observed for the ROP of D-lactide, and the nature of the ligands present significantly affected the observed catalytic activities and the properties of the resultant polylactides.