288105-09-9Relevant academic research and scientific papers
Immobilized Pd on a NHC-functionalized metal-organic FrameworkMIL-101(Cr): An efficient heterogeneous catalyst in the heck and copper-free Sonogashira coupling reactions
Niknam, Esmaeil,Panahi, Farhad,Khalafi-Nezhad, Ali
supporting information, (2021/01/12)
A heterogeneous palladium catalyst system based on immobilization of palladium moieties on a N-heterocyclic carbene (NHC) modified metal organic framework (MOF) was developed for the Heck and copper-free Sonogashira coupling reactions. In order to prepare this catalyst system, first, MIL-101(Cr) was functionalized with NHC moieties through a post synthetic modification (PSM) approach, and then Pd metal was stabilized on the prepered MIL-101(Cr)-NHC substrate. This material was characterized using various microscopic and spectroscopic techniques and then was used as an efficient heterogeneous Pd catalyst system in the Heck and copper-free Sonogashira reactions. Results of the heterogeneity tests showed that the Pd-NHC-MIL-101(Cr) catalyst can efficiently catalyzed these coupling reactions heterogeneously and no remarkable changes observed in the morphology and structure of MIL-101(Cr) template during the reaction progress. Also, existence of palladium nanoparticles immobilized on the MOF structure affirmed by the TEM and XPS analysis confirmed the oxidation state of Pd. A variety of alkene and alkyne derivatives were synthesized in good to excellent yields using this heterogeneous Pd catalyst system under normal conditions. More importantly Pd-NHC-MIL-101(Cr) catalyst was simply recovered from the reaction medium without remarkable decreasing in its catalytic activities after five times of reusability. The ICP analysis showed the very low Pd and Cr metals leaching, representing high stability and applicability of this catalyst in Pd coupling reactions.
Efficient nickel(II) naringenin-oxime complex catalyzed Mizoroki-Heck cross-coupling reaction in the presence of hydrazine hydrate
Song, Jin-Yi,Liu, Yang,Zhao, Hong-Yan,Han, Hua-Tao,Li, Zhuo-Fei,Guo, Wei-Hao,Chu, Wen-Yi,Sun, Zhi-Zhong
, p. 12288 - 12292 (2017/10/16)
A novel nickel(ii) naringenin-oxime complex was designed, synthesized and characterized. Therein, the nickel(ii) naringenin oxime complex as an efficient catalyst was used in Mizoroki-Heck coupling reactions of aryl halides containing electron-rich and electron-deficient substituents with styrene, methyl acrylate and divinylbenzene (DVB), respectively. The reaction proceeded efficiently under alkaline conditions in the presence of 0.30 mol% of the Ni(ii) naringenin oxime complexand N2H4·H2O as the reductant in EtOH at 80 °C, and 32 alkene products were afforded in moderate to excellent yields, containing four new olefins. The new catalytic system not only provided an inexpensive and efficient process with greener conditions, but also broadened the reaction scope.
Aldehyde-appended distyrylbenzenes: Amine recognition in water
Kumpf, Jan,Bunz, Uwe H. F.
, p. 8921 - 8924 (2012/09/25)
Change in water: Aqueous solutions of aldehyde-substituted, water-soluble distyrylbenzenes reacted with amines to give imines or aminals with dramatically changed fluorescence. This approach allowed the detection and recognition of amines in water (see fi
Synthesis, morphology, and optical properties of tetrahedral oligo(phenylenevinylene) materials
Wang, Shujun,Oldham Jr., Warren J.,Hudack Jr., Raymond A.,Bazan, Guillermo C.
, p. 5695 - 5709 (2007/10/03)
A novel topological strategy is described for designing amorphous molecular solids suitable for optoelectronic applications. In this approach, chromophores are attached to a tetrahedral point of convergence. Stilbenoid units were covalently linked to tetraphenylmethane, tetraphenyladamantane, or tetraphenylsilane cores using palladium catalyzed coupling methodology. Thus, reaction of E(C6H5X)4 (E = C and adamantane, X = I; E = Si, X = Br) with styrene or 4,4'-tert-butylvinylstilbene under Heck coupling conditions yields the corresponding tetrakis(stilbenyl) (E(STB)4) and tetrakis(4-tert- butylstyrylstilbenyl) (E((t)BuSSB)4) compounds. Similarly, reaction of 1,1- diphenyl-2-(4-dihydroxyboronphenyl)ethene or 2-(4-pinacolatoboronphenyl)-3,3- diphenylacrylonitrile with tetrakis(4-bromophenyl)methane using Suzuki coupling methodology gives tetrakis(4,4'-(2,2-diphenyl-vinyl)-1, 1'- biphenyl)methane (C(DPVBi)4) or tetrakis(4,4'-(3,3-diphenylacrylonitrile)- 1,1'-biphenyl)methane (C(DPAB)4), respectively, in good yields. Compounds with more extended conjugation can also be prepared. Thus, reaction of excess 1-(4'-tert-butylstyryl)-4-(4'-vinylstyryl)benzene with C(C6H4I)4 provides tetrakis(4-(4'-(4''-tert-butylstyryl)styryl)stilbenyl)methane (C(4R-(t)Bu)4) in low yield (~20%). The more soluble analogue, tetrakis(4-(4'-(3,5-di- tert-butylstyryl)styryl)stilbenyl)methane (C(4R-2(t)Bu)4) is prepared similarly using 1-(3',5'-di-tert-butylstyryl)-4-(4'-vinylstyryl)benzene and in better yield (~80%). Alkoxy substituents can also be used to increase solubility. Tetrakis((4-(2',5'-dioctyloxy-4'-styryl)styryl)stilbenyl)methane, C(4R-(OC8H17)2)4, was prepared by treatment of C(C6H4I)4 with excess 2,5-dioctyloxy-1-styryl-4(4'-vinylstyryl)benzene (yield ~73%). The simple stilbenyl-derivatives were found by DSC measurements and powder diffraction experiments to be crystalline compounds. Comparison of single-crystal X-ray diffraction data shows that C(STB)4 and Si(STB)4 form isomorphous crystals. The larger E((t)BuSSB)4, C(DPVBi)4, and C(DPAB)4 compounds readily form amorphous glasses with elevated glass transition temperatures (T(g) = 142190 °C) in the absence of solvent. Extending the conjugation length of the arm leads to more stable glasses. For example, the glass transition temperature of C(4R-(t)Bu)4 was measured at 230 °C. Solution phase optical spectroscopic data of E((t)BuSSB)4 (E = C, adamantane, and Si) are characteristic of the parent distyrylbenzene chromophore. Films, however, show broad and significantly red-shifted emission spectra. In contrast, C(DPVBi)4 gives absorption and emission spectra which are nearly identical between dilute solution phase samples and neat solid films. The emission of C(DPAB)4 is broad and structureless, reminiscent of exciplex or excimer emission. Films of the tetramers with longer arms (C(4R-(t)Bu)4, C(4R- 2(t)Bu)4, and C(4R-(OC8H17)2)4) show emission properties which are dependent on sample history. Annealing the sample at elevated temperature leads to red-shifted emission as a result of better interdigitation between the optically active fragments.
