Synthesis, characterization, and density functional theory studies of hydrazone–oxime ligand derived from 2,4,6‐trichlorophenyl hydrazine and its metal complexes searching for new antimicrobial drugs

2020 ◽  
Author(s):  
Mohamad M.E. Shakdofa ◽  
Nagy A. Morsy ◽  
Anas J. Rasras ◽  
Ahmed N. Al‐Hakimi ◽  
Adel M.E. Shakdofa
Keyword(s):  
Density Functional Theory ◽  
Metal Complexes ◽  
Density Functional ◽  
Antimicrobial Drugs ◽  
Functional Theory ◽  
Oxime Ligand

CO2 reduction catalysis by tunable square-planar transition-metal complexes: a theoretical investigation using nitrogen-substituted carbon nanotube models

2017 ◽  
Vol 19 (43) ◽  
pp. 29068-29076 ◽  
Author(s):  
Yu-Te Chan ◽  
Ming-Kang Tsai
Keyword(s):  
Density Functional Theory ◽  
Carbon Nanotube ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional ◽  
Co2 Reduction ◽  
Functional Theory ◽  
Square Planar ◽  
Planar Transition

The CO2 reduction capabilities of transition-metal-chelated nitrogen-substituted carbon nanotube models (TM-4N2v-CNT, TM = Fe, Ru, Os, Co, Rh, Ir, Ni, Pt or Cu) are characterized by density functional theory.

A density functional theory study of the mechanisms of addition of transition metal oxides ReO3L(L = Cl-, O-, OCH3, CH3) to substituted ketenes

2015 ◽  
Vol 14 (05) ◽  
pp. 1550035 ◽  
Author(s):  
Issahaku Ahmed ◽  
Richard Tia ◽  
Evans Adei
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Metal Complexes ◽  
Oxidation State ◽  
Density Functional ◽  
High Activation ◽  
Functional Theory ◽  
Activation Barriers ◽  
Reaction Energies ◽  
Addition Pathway

Ketenes are excellent precursors for catalytic asymmetric reactions, creating chiral centers mainly through addition across their C = C bonds. Density functional theory (DFT) calculations at the MO6/LACVP* and B3LYP/LACVP* levels of theory were employed in a systematic investigation of the peri-, chemo- and regio-selectivity of the addition of transition metal oxo complexes of the type ReO 3 L ( L = Cl -, O -, OCH 3, CH 3) to substituted ketenes O = C = C ( CH 3)(X) [ X = CH 3, H , CN , Ph ] with the aim of elucidating the effects of substituents on the mechanism of the reactions. The [2 + 2] addition pathway across the C = C or C = O (depending on the ligand) is the most preferred in the reactions of dimethyl ketene with all the metal complexes studied. The [2 + 2] pathway is also the most preferred in the reactions of ReO 3 Cl with all the substituted ketenes studied except when X = Cl . Thus of all the reactions studied, it is only the reaction of ReO 3 Cl with O = C = C ( CH 3)( Cl ) that prefers the [3 + 2] addition pathway. Reactions of dimethyl ketene with ReO 3 L favors addition across C = O bonds of the ketene when L = O - and CH 3 but favors addition across C = C bonds when L = OCH 3 and Cl . In the reactions of ReO 3 Cl with substituted ketenes, addition across C = O bonds is favored only when X = H while addition across C = C bonds is favored when X = CH 3, Cl , Ph , CN . The reactions of dimethyl ketene with ReO 3 L will most likely lead to the formation of an ester precursor in each case. A zwitterionic intermediate is formed in the reactions except in the reactions of [Formula: see text]. The order in the activation energies of the reactions of dimethyl ketenes with the metal complexes ReO 3 L with respect to changing ligand L is O - < CH 3 O - < Cl - < CH 3 while the order in reaction energies is CH 3 < CH 3 O - < O - < Cl -. For the reactions of substituted ketenes with ReO 3 Cl , the order in activation barriers is CH 3 < Ph < CN < Cl < H while the reaction energies follow the order Cl < CH 3 < H < Ph < CN . In the reactions of dimethyl ketenes with ReO 3 L , the trend in the selectivity of the reactions with respect to ligand L is Cl - < CH 3 O - < CH 3 < O - while the trend in selectivity is CH 3 < CN < Cl < Ph in the reactions of ReO 3 Cl with substituted ketenes. It is seen that reactions involving a change in oxidation state of metal from the reactant to product have high activation barriers while reactions that do not involve a change in oxidation state have low activation barriers. For both [3 + 2] and [2 + 2] additions, low activation barriers are obtained when the substituent on the ketene is electron-donating while high activation barriers are obtained when the substituent is electron-withdrawing.

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