Ordered Mesoporous and Microporous Molecular Sieves Functionalized with Transition Metal Complexes as Catalysts for Selective Organic Transformations

2002 ◽  
Vol 102 (10) ◽  
pp. 3615-3640 ◽  
Author(s):  
Dirk E. De Vos ◽  
Mieke Dams ◽  
Bert F. Sels ◽  
Pierre A. Jacobs
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Molecular Sieves ◽  
Organic Transformations ◽  
Ordered Mesoporous

scholarly journals Metal Complexes of Schiff Bases of 3-Hydroxyquinoxaline-2-carboxaldehyde Encapsulated in Zeolite Y Cages: Potential Catalyst for Removing Phenol from Effluent Media

2021 ◽  
Vol 33 (11) ◽  
pp. 2746-2754
Author(s):  
N.R. Suja ◽  
T.K. Bindu Sharmila ◽  
S.R. Amrutha
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Metal Complexes ◽  
Schiff Bases ◽  
Transition Metal Complexes ◽  
Zeolite Y ◽  
Point Of View ◽  
Organic Transformations ◽  
Efficient Catalyst ◽  
Industrial Pollutants

Transition metal complexes are known to be efficient catalyst for many organic transformations. Encapsulation of metal complexes in zeolite cage brings many significant modifications in the structure of the metal complexes, which are very interesting from the catalytic point of view. This study aims in a comparative evaluation of the influence of structure of neat and encapsulated complexes in their catalytic activity. Phenol is one of the major industrial pollutants. Heterogenizing transition metal Schiff bases by encapsulation inside the zeolite would help to minimize the reuse problem of transition metal complexes. This article deals with the synthesis, characterization and catalytic activity studies of Co(II), Ni(II) and Cu(II) complexes of 3-hydroxyquinoxaline-2-carboxaldehyde with ethylenediamine (L1) and an o-phenylene diamine (L2).

C-Methylation Of Organic Substrates: A Comprehensive Overview. Part Ii. Methanol As Methylating Agent. A Case Of Catalysis Versatility

2020 ◽  
Vol 17 ◽  
Author(s):  
Saad Moulay
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Molecular Sieves ◽  
Acid Sites ◽  
Lewis Base ◽  
Molar Ratio ◽  
Organic Substrates ◽  
Solid Catalysts ◽  
The Impact

: The present account surveys the results of the myriad of works on C-methylation of organic substrates with methanol as an eco-friendly methylating agent. The innumerable reports on this issue reveal the widespread use of a set of solid catalysts such as molecular sieves, zeolites, metal phosphates, metal oxides and transition metal complexes, to accomplish such methylation. One related facet was the impact of the numbers of Brønstëd acid sites, of Lewis acid sites, and of Lewis base sites present in solid catalysts, such as zeolites, their ratios, and their strengths that affect the distribution of the methylation products and their selectivities. Also, specific surface area and porosity for some solid catalysts such as zeolites play additional roles in the overall reaction. Not only these properties of a catalyst that influence the methylation outcome but also the temperature, space velocity (WHSV, LHSV, GSHV), weight of catalyst per reactant flow rate (W/F), time of stream (TOS), and methanol/substrate molar ratio. The treated substrates herein discussed were aromatic hydrocarbons (benzene, biphenyls, naphthalenes, toluene, xylenes), alkenes, phenolics (phenol, cresols, anisole), N-heteroarenes, carbonyls, alcohols, and nitriles. Methylation of benzene affords not only toluene as main product but also polymethylated benzenes (xylenes, pseudocumene, hexamethylenebenzene, and also ethylbenzene as a sidechain product). Also, toluene is sensitive to the reaction conditions, giving rising to ring methylation and to sidechain one (ethylbenzene and styrene), besides the formation of benzene as a disproportionation product. Wealth of results from the methylation of phenolic compounds bears witness to the interest of different investigators in this special research. As to these phenolics, concurrent O-methylation inevitably parallels the C-methylation, and the selectivity of the latter one remains depended on the above-cited factors; ortho-cresol and 2,6-xylenol have been the main C-ring methylated phenols. Methylation of olefins with methanol over solid catalysts, leading to higher olefins, is of a great interest. The chemistry involved in the methylation of N-heteroarenes such as pyridines, indoles, and pyrroles is significant. Application of the methylation protocols, using methanol as a reagent and transition metal complexes as catalysts, to ketones, esters, aldehydes, nitriles, and alcohols, ends up with some important molecules such as acrylonitrile (a monomer) and isobutanol (a biofuel).

C-methylation of organic substrates: A comprehensive overview. Part iiia. Methanol as a methylating agent. A case of catalysis versatility

2021 ◽  
Vol 18 ◽  
Author(s):  
Saad Moulay
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Molecular Sieves ◽  
Acid Sites ◽  
Lewis Base ◽  
Side Chain ◽  
Organic Substrates ◽  
Solid Catalysts ◽  
The Impact

: The present account surveys the results of the myriad of works on the C-methylation of organic substrates with methanol as an eco-friendly methylating agent. The innumerable reports on this issue reveal the widespread use of a set of solid catalysts such as molecular sieves, zeolites, metal phosphates, metal oxides and transition metal complexes to accomplish such methylation. One related facet was the impact of the numbers of Brønstëd acid sites, Lewis acid sites, and Lewis base sites present in solid catalysts, such as zeolites, ratios, and strengths that affect the distribution of the methylation products and their selectivities. Moreover, specific surface area and porosity for some solid catalysts, such as zeolites, play additional roles in the overall reaction. Not only do these catalyst properties influence the methylation outcome, but the temperature, space velocity (WHSV, LHSV, GSHV), weight of catalyst per reactant flow rate (W/F), time of stream (TOS), and methanol/substrate molar ratio also do. The treated substrates herein discussed were aromatic hydrocarbons (benzene, biphenyls, naphthalenes, toluene, xylenes), alkenes, phenolics (phenol, cresols, anisole), N-heteroarenes, carbonyls, alcohols, and nitriles. Methylation of benzene affords not only toluene as the main product but also polymethylated benzenes (xylenes, pseudocumene, hexamethylenebenzene, and also ethylbenzene as a side-chain product). Furthermore, toluene is sensitive to the reaction conditions, giving rise to ring methylation and side-chain one (ethylbenzene and styrene), besides the formation of benzene as a disproportionation product. A number of results from the methylation of phenolic compounds bear witness to the interest of different investigators in this special research. As to these phenolics, concurrent O-methylation inevitably parallels the C-methylation, and the selectivity of the latter one remains dependent on the above-cited factors; ortho-cresol and 2,6-xylenol have been the main C-ring methylated phenols. Methylation of olefins with methanol over solid catalysts, leading to higher olefins, is of great interest. The chemistry involved in the methylation of N-heteroarenes, such as pyridines, indoles, and pyrroles, is significant. Application of the methylation protocols, using methanol as a reagent and transition metal complexes as catalysts to ketones, esters, aldehydes, nitriles, and alcohols, ends up with some important molecules such as acrylonitrile (a monomer) and isobutanol (a biofuel).

Straightforward synthesis and catalytic applications of rigid N,O-type calixarene ligands

2015 ◽  
Vol 13 (46) ◽  
pp. 11189-11193 ◽  
Author(s):  
Varun Rawat ◽  
Konstantin Press ◽  
Israel Goldberg ◽  
Arkadi Vigalok
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Main Group ◽  
Late Transition Metal ◽  
Organic Transformations ◽  
One Step ◽  
Catalytic Applications ◽  
Late Transition

Here, we report a simple one-step access to new rigid N,O-calixarene ligands which is based on copper-catalized amination at the lower rim. We also present their main group and late transition metal complexes which show superior catalytic activity, in several organic transformations, compared with known metal calixarene complexes.

Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Carbene Complexes ◽  
New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

Density Functional Calculations of EPR Parameter g Tensors of Some Transition Metal Complexes

2011 ◽  
Vol 2 (2) ◽  
pp. 139-141
Author(s):  
Vinita Prajapati ◽  
◽  
P.L.Verma P.L.Verma ◽  
Dhirendra Prajapati ◽  
B.K.Gupta B.K.Gupta
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional Calculations ◽  
Density Functional
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