scholarly journals Dinuclear thiolato-bridged arene ruthenium complexes: from reaction conditions and mechanism to synthesis of new complexes

RSC Advances ◽  
2020 ◽  
Vol 10 (66) ◽  
pp. 40106-40116
Author(s):  
Hedvika Primasová ◽  
Silviya Ninova ◽  
Mario de Capitani ◽  
Jana Daepp ◽  
Ulrich Aschauer ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Reaction Mechanisms ◽  
Ruthenium Complexes ◽  
Synthetic Route ◽  
Reaction Conditions

We used DFT calculations to understand the reaction mechanisms leading to the formation of dinuclear thiophenolato-bridged arene ruthenium complexes. DFT prompted us to modify the usual synthetic route, which enabled the synthesis of new complexes.

Synthetic Route of Trithiolato-Bridged Dinuclear Arene Ruthenium(II) Complexes [(η6-P-MeC6H4Pri)2Ru2(μ2-SR)3]+

2020 ◽  
Author(s):  
Hedvika Primasova ◽  
Silviya Ninova ◽  
Ulrich Aschauer ◽  
julien Furrer ◽  
Mario de Capitani ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Metal Complexes ◽  
Density Functional ◽  
Ruthenium Complexes ◽  
Experimental Results ◽  
Dft Study ◽  
Synthetic Route ◽  
Functional Theory ◽  
Fundamental Understanding

Several dinuclear thiophenolato-bridged arene ruthenium complexes [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-R)3]+ could so far only<br>be obtained with moderate yields using the synthetic route established in the early 2000s. With much less reactive aliphatic<br>thiols or with bulky thiols, the reactions become even less efficient and the desired complexes are obtained with low yields<br>or not at all. We employed density functional theory (DFT) calculations to gain a fundamental understanding of the reaction<br>mechanisms leading to the formation of dithiolato and trithiolato complexes starting from the dichloro(pcymene)<br>ruthenium(II) dimer [(η6-p-MeC6H4Pri)Ru(μ2-Cl)Cl]2. The results of the DFT study enabled us to rationalise<br>experimental results and allowed us, via a modified synthetic route, to synthesise previously unreported and hitherto<br>considered as unrealistic complexes. Our study opens possibilities for the synthesis of so far inaccessible thiolato-bridged<br>dinuclear arene ruthenium(II) complexes but more generally also the synthesis of other thiolato-bridged dinuclear group 8<br>and 9 metal complexes could be reexamined.

scholarly journals Synthetic Route of Trithiolato-Bridged Dinuclear Arene Ruthenium(II) Complexes [(η6-P-MeC6H4Pri)2Ru2(μ2-SR)3]+

2020 ◽  
Author(s):  
Hedvika Primasova ◽  
Silviya Ninova ◽  
Ulrich Aschauer ◽  
julien Furrer
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Reaction Mechanisms ◽  
Density Functional ◽  
Experimental Results ◽  
Dft Study ◽  
Synthetic Route ◽  
Functional Theory ◽  
Fundamental Understanding ◽  
Aliphatic Thiols

Several dinuclear trithiophenolato-bridged arene ruthenium complexes [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-R)3]+ could so far only be obtained with moderate yields using the synthetic route established in the early 2000s. With much less reactive aliphatic thiols or with bulky thiols, the reactions become even less efficient and the desired trithiolato complexes are obtained either only with bad yields or not at all. We employ density functional theory (DFT) calculations to gain a fundamental understanding of the reaction mechanisms leading to the formation of trithiolato complexes starting from the dichloro(p-cymene)ruthenium(II) dimer [(η6-p-MeC6H4Pri)Ru(μ2-Cl)Cl]2. The results of this DFT study enable us to rationalize experimental results and allow us, via a modified synthetic route, to synthesize the previously unreported and hitherto considered as unrealistic trithiolato complex [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H11)3]+. Our DFT study opens possibilities for the synthesis of so far inaccessible thiolato-bridged dinuclear arene ruthenium(II) complexes but more generally also the synthesis of other thiolato-bridged dinuclear group 8 and 9 metal com-plexes could be reexamined.

scholarly journals Synthetic Route of Trithiolato-Bridged Dinuclear Arene Ruthenium(II) Complexes [(η6-P-MeC6H4Pri)2Ru2(μ2-SR)3]+

2020 ◽  
Author(s):  
Hedvika Primasova ◽  
Silviya Ninova ◽  
Ulrich Aschauer ◽  
julien Furrer ◽  
Mario de Capitani ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Metal Complexes ◽  
Density Functional ◽  
Ruthenium Complexes ◽  
Experimental Results ◽  
Dft Study ◽  
Synthetic Route ◽  
Functional Theory ◽  
Fundamental Understanding

Several dinuclear thiophenolato-bridged arene ruthenium complexes [(η6-p-MeC6H4Pri)2Ru2(μ2-SC6H4-R)3]+ could so far only<br>be obtained with moderate yields using the synthetic route established in the early 2000s. With much less reactive aliphatic<br>thiols or with bulky thiols, the reactions become even less efficient and the desired complexes are obtained with low yields<br>or not at all. We employed density functional theory (DFT) calculations to gain a fundamental understanding of the reaction<br>mechanisms leading to the formation of dithiolato and trithiolato complexes starting from the dichloro(pcymene)<br>ruthenium(II) dimer [(η6-p-MeC6H4Pri)Ru(μ2-Cl)Cl]2. The results of the DFT study enabled us to rationalise<br>experimental results and allowed us, via a modified synthetic route, to synthesise previously unreported and hitherto<br>considered as unrealistic complexes. Our study opens possibilities for the synthesis of so far inaccessible thiolato-bridged<br>dinuclear arene ruthenium(II) complexes but more generally also the synthesis of other thiolato-bridged dinuclear group 8<br>and 9 metal complexes could be reexamined.

DFT Study and Synthesis of Novel Bioactive Bispyrazole Using Mg/AlLDH as a Solid Base Catalyst

2020 ◽  
Vol 14 ◽  
Author(s):  
Soufiane Akhramez ◽  
Youness Achour ◽  
Mustapha Diba ◽  
Lahoucine Bahsis ◽  
Hajiba Ouchetto ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Experimental Finding ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Mechanistic Study ◽  
Knoevenagel Reaction ◽  
Solid Base ◽  
Reaction Conditions ◽  
Aryl Aldehyde

Background: In this study, an efficient synthesis of novel bispyrazole heterocyclic molecules by condensation of substituted aromatic aldehydes with 1,3-diketo-N-phenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst is reported. The attractive features of this protocol are as follows: mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Methods: The bispyrazole derivatives 3a-m were prepared by condensation reaction of substituted aromatic aldehydes with 1,3-diketo-Nphenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst under THF solvent at the refluxing temperature. Objective: To synthesize a novel bispyrazole heterocyclic molecule may be have important biological activities and thus can be good candidates for pharmaceutical applications. Results: This protocol describes the Synthesis of Bioactive Compounds under mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Conclusion: In summary, the pharmacologically interesting bis-pyrazole derivatives have been synthesized through Mg/Al-LDH as a solid base catalyst, in THF as solvent. Thus, the synthesized bioactive compounds containing the pyrazole ring may be have important biological activities and thus can be good candidates for pharmaceutical applications. Therefore, the catalyst Mg/Al-LDH showed high catalytic activity. Besides, a series of bispyrazole molecules were synthesized with a good yield and easy separation of the catalyst by simple filtration. Moreover, DFT calculations and reactivity indexes are used to explain the selectivity of the condensation reaction between aryl benzaldehyde and 1,3-diketo-Nphenylpyrazole via Knoevenagel reaction, and the results are in good agreement with the experimental finding.

scholarly journals A two step synthesis of a key unit B precursor of cryptophycins by asymmetric hydrogenation

2011 ◽  
Vol 7 ◽  
pp. 243-245 ◽  
Author(s):  
Benedikt Sammet ◽  
Mathilde Brax ◽  
Norbert Sewald
Keyword(s):  
Asymmetric Hydrogenation ◽  
Synthetic Route ◽  
Reaction Conditions ◽  
High Yields

A novel highly enantioselective two step access to a unit B precursor of cryptophycins in good yields from commercially available starting materials has been developed. The key step is an asymmetric hydrogenation using the commercially available [(COD)Rh-(R,R)-Et-DuPhos]BF4 catalyst. The synthetic route provides the advantage of less synthetic steps, proceeds with high yields and enantioselectivity, and avoids hazardous reaction conditions.

scholarly journals Generation of 1,2-oxathiolium ions from (arysulfonyl)- and (arylsulfinyl)allenes in Brønsted acids. NMR and DFT study of these cations and their reactions

2018 ◽  
Vol 14 ◽  
pp. 2897-2906 ◽  
Author(s):  
Stanislav V Lozovskiy ◽  
Alexander Yu Ivanov ◽  
Olesya V Khoroshilova ◽  
Aleksander V Vasilyev
Keyword(s):  
Dft Calculations ◽  
Reaction Mechanisms ◽  
Dft Study ◽  
Bronsted Acids ◽  
Allyl Alcohols ◽  
High Yields ◽  
Hydrolysis Of

In strong Brønsted acids (CF3SO3H, FSO3H, D2SO4), (arysulfonyl)allenes (ArSO2–CR1=C=CR2R3) and (arylsulfinyl)allenes (ArSO–CR1=C=CR2R3) undergo cyclization into the corresponding stable 1,2-oxathiolium ions, which were studied by means of NMR and DFT calculations. Quenching of solutions of these cations with low nucleophilic media, aqueous HCl, leads to their deprotonation with a stereoselective formation of (arysulfonyl)butadienes (for instance, ArSO2–CR1=C–C(Me)=CH2, for R2 = R3 = Me, yields of 87–98%). Reactions of (arysulfonyl)allenes in the system TfOH (0.1 equiv)–HFIP (hexafluoropropan-2-ol) followed by hydrolysis give rise to allyl alcohols (ArSO2–CR1=CH–C(OH)R2R3, yields of 78–99%). Reflux of solutions of (arysulfonyl)allenes in the presence of TfOH (1 equiv) in 1,2-dichlorobenzene leads to the cyclization into thiochromene 1,1-dioxides in high yields. Under the action of TfOH or AlX3 (X = Cl, Br) followed by hydrolysis of reaction mixtures, (arylsulfinyl)allenes give allyl alcohols (ArSO2–CR1=CH–C(OH)R2R3). Plausible reaction mechanisms have been proposed for all studied reactions.

Dodecanamide Concrete Foaming Agent: Preparation and Application

2011 ◽  
Vol 71-78 ◽  
pp. 799-802
Author(s):  
Cai Lin Liu ◽  
Yu Rong Zhang ◽  
Hai Jun Yang ◽  
Xian Yan Ren ◽  
Jun Xiao Yang
Keyword(s):  
Chloroacetic Acid ◽  
Foaming Properties ◽  
Dodecanoic Acid ◽  
Temperature Reaction ◽  
Synthetic Route ◽  
Foam Concrete ◽  
Reaction Conditions ◽  
Available N ◽  
Foaming Agent ◽  
Molar Ratios

A lauramide concrete foaming agent was prepared by a simple synthetic route using readily available N-(2-hydroxyethyl)ethylenediamine, dodecanoic acid, and chloroacetic acid. The reaction conditions were optimized by changing reaction temperature, reaction time, and/or molar ratios of reactants. Significantly, the concrete foaming agent has very low surface tension and good foaming properties, which could be directly used without purification and has widely applicable potentials in low-density foam concrete.

Addressing the uncertainty of DFT-determined hydrogenation mechanisms over coinage metal surfaces

2020 ◽  
Author(s):  
Kunran Yang ◽  
Bo Yang
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Reaction Mechanisms ◽  
Metal Surfaces ◽  
Density Functional ◽  
Functional Theory ◽  
Coinage Metal

Density functional theory (DFT) has been considered as a powerful tool for the identification of reaction mechanisms. However, it is still unclear whether the error of DFT calculations would lead...

scholarly journals Isoxazolium N-ylides and 1-oxa-5-azahexa-1,3,5-trienes on the way from isoxazoles to 2H-1,3-oxazines

2014 ◽  
Vol 10 ◽  
pp. 1896-1905 ◽  
Author(s):  
Alexander F Khlebnikov ◽  
Mikhail S Novikov ◽  
Yelizaveta G Gorbunova ◽  
Ekaterina E Galenko ◽  
Kirill I Mikhailov ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Experimental Studies ◽  
Diazo Compounds ◽  
Stationary Points ◽  
Reaction Intermediates ◽  
Reaction Conditions ◽  
Open Chain ◽  
Isoxazole Ring ◽  
Diazo Esters ◽  
Probable Reaction

Theoretical and experimental studies of the reaction of isoxazoles with diazo compounds show that the formation of 2H-1,3-oxazines proceeds via the formation of (3Z)-1-oxa-5-azahexa-1,3,5-trienes which undergo a 6π-cyclization. The stationary points corresponding to the probable reaction intermediates, isoxazolium N-ylides, were located by DFT calculations at the B3LYP/6-31G(d) level only for derivatives without a substituent in position 3 of the isoxazole ring. These isoxazolium N-ylides are thermodynamically and kinetically very unstable. According to the calculations and experimental results 2H-1,3-oxazines are usually more thermodynamically stable than the corresponding open-chain isomers, (3Z)-1-oxa-5-azahexa-1,3,5-trienes. The exception are oxaazahexatrienes derived from 5-alkoxyisoxazoles, which are thermodynamically more stable than the corresponding 2H-1,3-oxazines. Therefore, the reaction of diazo esters with 5-alkoxyisoxazoles is a good approach to 1,4-di(alkoxycarbonyl)-2-azabuta-1,3-dienes. The reaction conditions for the preparation of aryl- and halogen-substituted 2H-1,3-oxazines and 1,4-di(alkoxycarbonyl)-2-azabuta-1,3-dienes from isoxazoles were investigated.

scholarly journals Full N,N-Methylation of 4,4′-Methylenedianiline with Dimethyl Carbonate: A Feasible Access to 4,4′-Methylene bis(N,N-Dimethylaniline)

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Zegang Qiu ◽  
Kunjie Wang ◽  
Zhiqin Li ◽  
Tao Li ◽  
Jinhao Bai ◽  
...  
Keyword(s):  
Zinc Acetate ◽  
Dimethyl Carbonate ◽  
Reaction Pathway ◽  
Major Product ◽  
High Yield ◽  
Synthetic Route ◽  
Reaction Conditions ◽  
High Yields ◽  
By Products

The full N,N-methylation of 4,4′-methylenedianiline (MDA) with dimethyl carbonate (DMC) was investigated. The yield of the major product 4,4′-methylene bis(N,N-dimethylaniline) (MBDMA) reached as high as 97% over NaY catalyst at 190°C for 6 h. The catalyst could be used for two more times with acceptable MBDMA yields higher than 90%. The main by-products were identified as three N-methylated derivatives. Surprisingly, the formation of the N-methoxycarbonylation product was extremely restrained, which could be produced in high yields of 98% on zinc acetate catalyst. Furthermore, the reaction pathway to the major product MBDMA was proposed. Finally, a feasible synthetic route of 4,4′-methylene bis(N,N-dimethylaniline) (MBDMA) was established, featuring a high yield, mild reaction conditions, and simple operations.

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