668-29-1Relevant articles and documents
Hexaphenylbenzene based push-pull fluorophores displaying intriguing polarity-dependent fluorescence behavior, AIE(E) characteristics and mega-large Stokes shifts
Cao, Xiaohui,Li, Si,Li, Yan,Xu, Bo,Yang, Qiusheng,Yin, Guohui,Zhang, Yuecheng,Zhao, Jiquan
, (2021/12/10)
In general, most donor-acceptor type fluorophores are known to exhibit solvatochromic behavior and obey the energy gap law simultaneously, showing decreased emission with increasing solvent polarity. In this work, four push-pull hexaphenylbenzene (HPB) derivatives 1–4 have been designed and synthesized by introducing methoxy and dicyanovinyl groups at the tip of aromatic blades, which behave exceptionally polarity-dependent emission properties. In the low to medium solvent polarity region, the four dipole fluorophores display gradually enhanced fluorescence, whereas a reverse trend is observed with the further increase of solvent polarity. Meanwhile, 1–4 are found to exhibit the strongest emission at the same wavelength remarkably, which appears to be somewhat relevant to the intrinsic characteristics of dicyanovinyl-phenyl acceptor. A mechanistic scheme containing a conical intersection (CI) has been proposed to explain the up-down emission of 1–4 with increasing solvent polarity. Large Stokes shifts (up to 254 nm) and AIE(E) characteristics have also been achieved in these four HPB fluorophores. Besides, fluorophores 1–4 exhibit obvious freezing-solution induced chromism (FSIC), demonstrating an enhancement of the local matrix polarity upon freezing solutions.
Application of silica-supported Shvo's catalysts for transfer hydrogenation of levulinic acid with formic acid
He, Dongmei,Horváth, István T.
, p. 263 - 269 (2017/09/12)
Two triethoxysilylpropoxy-functionalized Shvo's catalyst precursors were synthesized and characterized by IR, NMR and HRMS. Both covalent anchoring and sol-gel methods were used for their immobilization. The homogeneous and immobilized catalysts were used for the transfer hydrogenation of levulinic acid with formic acid to form hydroxyvaleric acid, which was readily dehydrated to yield gamma-valerolactone. The immobilized catalysts prepared by the sol-gel method showed higher activity than the covalently grafted catalysts. Hot filtration tests showed no leaching of the immobilized Shvo's catalysts, opening the door to facile catalyst recycling.
Microwave-assisted synthesis of functionalized Shvo-type complexes
Cesari, Cristiana,Sambri, Letizia,Zacchini, Stefano,Zanotti, Valerio,Mazzoni, Rita
, p. 2814 - 2819 (2014/06/24)
A simple and expeditious microwave-assisted procedure for the synthesis of a variety of Shvo-type ruthenium complexes has been developed by reacting Ru3(CO)12 with variously functionalized tetraarylcyclopentadienones under microwave irradiation in MeOH. Ligand precursors have also been prepared under microwave heating by a bis-aldol condensation of 1,3-diphenylacetone with variously functionalized aromatic diketones. All the reactions were very fast and clean, leading to good yields and purities.