- Alumina as Solid-State Ligand in Enhancing the Redox Catalytic Property of Iron Oxide Grafted AlSBA-15 towards Arylation of Arene
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2–8 wt % iron has been grafted over SBA-15 and 10 wt % alumina grafted SBA-15 (AlSBA-15) through selective extraction deposition technique using LaFeO3 as iron precursor in acidic solution. DRS-UV spectra confirmed the presence of iron as isolated Fe(III), Fe(III)-clusters and amorphous FeOx oligomers. SEM-EDX mapping, FT-IR, XPS, HR-TEM and 27Al MAS NMR characterisation results confirmed that iron grafted over AlSBA-15 preferentially reside on the alumina. The donor-acceptor interaction of grafted iron ions with alumina atoms displaying Lewis acid properties stabilized iron at higher oxidation state Fe(III+δ). This increased the BE of Fe2p electrons (XPS) and shifted the temperature of iron reduction in 2–8 wt %Fe/AlSBA-15 materials to higher value (600 °C) compared with Fe/SBA-15 (H2-TPR). In arylation of benzene, 8 wt %Fe/AlSBA-15 demonstrated excellent redox catalytic activity with TOF close to homogeneous catalyst and 82 % biphenyl yield. The catalyst demonstrated consistent catalytic performance for 7 cycles.
- Rajendran, Chandran,Thirumoorthy, Kulandaivellu,Satishkumar, Govindaswamy,Landau, Miron V.
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p. 4768 - 4776
(2018/10/02)
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- Pd-catalyzed divergent trifluoroethylation and arylation of arylboronic acids by aryl(2,2,2-trifluoroethyl)iodonium triflates
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Highly electrophilic aryl(2,2,2-trifluoroethyl)iodonium triflates have been used for the first time as trifluoroethyl and aryl transfer reagents in Pd-catalyzed functionalization of arylboronic acids. Electron-rich arylboronic acids reacted with aryl(2,2,
- Yang, Jing,Han, Qiu-Yan,Zhao, Cheng-Long,Dong, Tao,Hou, Zhi-Yuan,Qin, Hua-Li,Zhang, Cheng-Pan
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supporting information
p. 7654 - 7658
(2016/08/24)
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- An efficient Pd/Al(OH)3 nanoparticle catalyst for Suzuki coupling reactions of aryl halides
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A high-performance palladium-based Pd/Al(OH)3 catalyst has been prepared by the one-pot three-component method. It was found that this 'ligandless' Pd/Al(OH)3 catalyst showed remarkable reactivity and gave excellent yields (up to 99%) towards the condensation of aryl bromides with various arylboronic acids under mild conditions, and afforded good yields of the coupling products (up to 97%) with most aryl chlorides in two different catalytic systems. Furthermore, this catalyst could be easily recovered through filtration and reused for 8 cycles without significant loss of the yield.
- Li, Xing,Chen, Wenwen,Chang, Honghong,Shao, Zhongqi,Wei, Wenlong
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p. 1593 - 1602
(2014/06/23)
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- Palladium-catalyzed Suzuki cross-couplings of N′-mesyl arylhydrazines via C-N bond cleavage
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An efficient palladium-catalyzed Suzuki cross-coupling reaction of N′-mesyl arylhydrazine with aryl boronic acid is described, which affords the corresponding biaryl compounds in high yields. This transformation proceeds through C-N bond cleavage under mi
- Zhou, He-Ping,Liu, Jin-Biao,Yuan, Jian-Jun,Peng, Yi-Yuan
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p. 25576 - 25579
(2014/07/07)
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- Palladium-bis(oxazoline) complexes with inherent chirality: Synthesis, crystal structures and applications in Suzuki, Heck and Sonogashira coupling reactions
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New palladium-bis(oxazoline) (Pd-BOX) complexes were synthesized and characterized. The X-ray crystal structures of the two complexes showed that the palladium ion is bound to the nitrogen atoms of the two heterocycles of the bidentate ligand and two chloride ions in a distorted square planar geometry. The coordination to the palladium ion allows these non C2-symmetric bis(oxazoline) ligand-based complexes to acquire a rigid backbone curvature generating an inherent chirality. The catalytic activities were evaluated in Suzuki-Miyaura, Mizoroki-Heck and Sonogashira coupling reactions. The complexes showed high catalytic activities towards numerous C-C coupling reactions with various aryl halides, aryl boronic acids, alkenes and alkynes. The reactions were optimized for the most suitable temperature, solvent, and base system.
- Shakil Hussain,Ibrahim, Mansur B.,Fazal, Atif,Suleiman, Rami,Fettouhi, Mohammed,El Ali, Bassam
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- Palladium chloride/tetraphenylphosphonium bromide intercalated clay: New catalyst for cross-coupling of aryl halides with arylboronic acids
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A facile method for the preparation of biaryl compounds is described from readily accessible aryl halides and arylboronic acids using palladium chloride/tetraphenylphosphonium bromide intercalated clay as a new catalyst.
- Varma, Rajender S.,Naicker, Kannan P.
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p. 439 - 442
(2007/10/03)
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- Polychlorinated biphenyl reductive dechlorination by vitamin B12s: Thermodynamics and regiospecificity
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Microbial reductive dechlorination reactions play an important role in determining the environmental fate of polychlorinated biphenyls (PCBs), especially for PCB congeners with more than four chlorines. Powerful chemical catalysts such as vitamin B12s provide an effective tool for the study of reductive dechlorination reactions. The reductive dechlorination of PCBs by titanium(III) citrate-reduced vitamin B12s was studied in batch reactors. Long-term experiments demonstrated reductive dechlorination of aqueous and sediment-sorbed 2,3,4,5,6-pentachlorobiphenyl (2,3,4,5,6-PeCB) to tetra-, tri-, di-, and monochlorobiphenyl products. Approximately 10% chlorine removal was observed in 36 days in aqueous experiments at 20°C; the sediment experiment showed 40% chlorine removal in 42 days at 30°C. Nearly all possible intermediates were produced and reductively dechlorinated, with no apparent accumulation of individual congeners. Short-term experiments were conducted to determine the pathway forvitamin B12s-catalyzed reductive dechlorination of aqueous 2,3,4,5,6-PeCB and its dechlorinated products; relative product distributions were measured for all possible tetra-and trichlorobiphenyl reductive dechlorination reactions. Theoretical product distributions based on free energies of formation agreed with observed product distributions for short-and long-term experiments. Reductive dechlorination was favored at positions with adjacent chlorines; on average, chlorines were removed equally from ortho, meta, and para positions.
- Woods, Sandra L.,Trobaugh, Darin J.,Carter, Kim J.
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p. 857 - 863
(2007/10/03)
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