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51.
Dr. Dennis Rottschäfer Beate Neumann Dr. Hans-Georg Stammler Dr. Tetiana Sergeieva Dr. Diego M. Andrada Dr. Rajendra S. Ghadwal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(9):3055-3064
Herein, we report the first 1,4-diphosphinine-1,4-diide compound [(ADCPh)P]2 ( 5-Ph ) (ADCPh=PhC{(NDipp)C}2; Dipp=2,6-iPr2C6H3) derived from an anionic dicarbene (ADCPh) as a red crystalline solid. Compound 5-Ph containing a 16π-electron planar fused-tricyclic ring system was obtained by the 4e reduction of [(ADCPh)PCl2]2 ( 4-Ph ) with Mg (or KC8) in a quantitative yield. Experimental and computational results imply that the central 8π-electrons C4P2 ring of 5-Ph , which is fused between two 6π-electrons C3N2 aromatic rings, is antiaromatic. Thus, each of the phosphorus atoms of 5-Ph has two electron-lone-pairs, one in a p-type orbital is in conjugation with the C=C bonds of the C4P2 ring, while the second resides in a σ-symmetric orbital. This can be shown with the gold complex [(ADCPh)P(AuCl)2]2 ( 6-Ph ) obtained by reacting 5-Ph with (Me2S)AuCl. A mixture of 5-Ph and 4-Ph undergoes comproportionation in the presence of MgCl2 to form the intermediate oxidation state compound [(ADCAr)P]2(MgCl4) ( 7-Ph ), which is an aromatic species. 相似文献
52.
ZSM‐5 Zeolite Nanosheets with Improved Catalytic Activity Synthesized Using a New Class of Structure‐Directing Agents 下载免费PDF全文
Rajkumar Kore Dr. Rajendra Srivastava Dr. Biswarup Satpati 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(36):11511-11521
A new series of multiquaternary ammonium structure‐directing agents, based on 1,4‐diazabicyclo[2.2.2]octane, was prepared. ZSM‐5 zeolites with nanosheet morphology (10 nm crystal thickness) were synthesized under hydrothermal conditions using multiquaternary ammonium surfactants as the zeolite structure‐generating agents. Both wide‐angle and small‐angle diffraction patterns were obtained using only a suitable structure‐directing agent under a specific zeolite synthesis composition. A mechanism of zeolite formation is proposed based on the results obtained from various physicochemical characterizations. ZSM‐5 materials were investigated in catalytic reactions requiring medium to strong acidity, which are important for the synthesis of a wide range of industrially important fine and specialty chemicals. The catalytic activity of ZSM‐5 materials was compared with that of the conventional ZSM‐5 and amorphous mesoporous aluminosilicate Al‐MCM‐41. The synthesis strategy of the present investigation using the new series of structure‐directing agents could be extended for the synthesis of other related zeolites or other porous materials in the future. Zeolite with a structural feature as small as the size of a unit cell (5–10 nm) with hierarchically ordered porous structure would be very promising for catalysis. 相似文献
53.
Novel one-pot synthesis of 4H-chromene derivatives using amino functionalized silica gel catalyst 总被引:2,自引:2,他引:0
Vijaykumar M.Joshi Rupali L.Magar Prashant B.Throat Sunil U.Tekale Bhagavan R.Patil Mangal P.Kale Rajendra P.Pawar 《中国化学快报》2014,25(3):455-458
A simple, efficient, and environmentally benign method for the synthesis of 4H-chromene derivatives was developed using well ordered and recoverable amino functionalized silica gel as a base catalyst. The 4H-chromene derivatives were obtained in short time and excellent yield(87%–96%) by three component reaction of aldehydes, malononitrile and cyclic 1,3-diketones in water at 70 8C. 相似文献
54.
Patil Seema P. Jadhav Sanjay N. Rode Chandrashekhar V. Shejwal Rajendra V. Kumbhar Arjun S. 《Transition Metal Chemistry》2020,45(6):403-411
Transition Metal Chemistry - A simple and efficient protocol for the ligand-free Mizoroki–Heck coupling reaction of various aryl bromides with different olefins has been reported by using in... 相似文献
55.
The conversion of CO2 to useful chemicals, especially to atom economical products, is the best approach to utilize an excess of CO2 present in the atmosphere. In this study, a metal‐organic framework (ZIF‐8) is integrated with nanocrystalline zirconosilicate zeolite to develop an integrated porous catalyst for CO2 insertion reactions. The catalyst exhibits excellent activity for the CO2 insertion reaction of epoxide to produce cyclic carbonate in neat condition without the addition of any co‐catalyst. The catalyst is stable and recyclable during the cyclic carbonate synthesis. Further, the catalyst also exhibits very good activity in another CO2 insertion reaction to produce quinazoline‐2,4(1H, 3H)‐dione. 相似文献
56.
Swapnil R. Sarda Jagpal D. Kale Sunil K. Wasmatkar Vijay S. Kadam Pravin G. Ingole Wamanrao N. Jadhav Rajendra P. Pawar 《Molecular diversity》2009,13(4):545-549
Chalcones on condensation with malononitrile and ammonium acetate in the presence of ionic liquid ethylammonium nitrate affords
the corresponding 2-amino-4, 6-diphenylpyridine-3-carbonitrile in excellent yield. The ionic liquid is recycled and reused
several times. 相似文献
57.
58.
Patel Sunil V. Patel Palak R. Patel Samir G. Kanaki Niranjan S. Patel Rajendra K. Patel Archita J. 《平面色谱法杂志一现代薄层色谱法》2016,29(5):380-387
JPC – Journal of Planar Chromatography – Modern TLC - This work represents the validation of a stability-indicating thin-layer chromatographic technique for the simultaneous estimation... 相似文献
59.
The paper presents results of flow visualization and mass transfer studies for fully developed turbulent flow of air in a
square section wind tunnel with repeated chamfered rib roughness on the bottom of the tunnel (rib head chamfer angles ϕ of
-15°, 0°, and 15°; relative roughness pitchp/e = 3, 5, 7.5, and 10). Direct video recordings of flow patterns were made using a simple technique of particles visualization.
For the positively chamfered closely spaced ribs (p/e <- 5) vigorous vortex shedding has been seen compared to the square or negatively chamfered ribs, which is found to be a
function of the Reynolds number. For the widely spaced ribs, the study shows flow separation at the ribs and reattachment
in the inter-rib region. Local mass transfer studies, based on the variation in colour of cobaltous chloride solution impregnated
paper due to evaporation of water, showed a significant improvement in mass transfer rate in the recirculating region in the
wake of ribs with the change in the chamfer angle from -15° to 15°. The positively chamfered 15° ribs are found to be better
than square section ribs atp/e <- 7.5. The performance of negatively chamfered ribs is found to be poor compared to other ribs irrespective of the relative
roughness pitch. 相似文献
60.