scholarly journals Meisenheimer complexes as hidden intermediates in the aza-SNAr mechanism

2020 ◽  
Vol 18 (22) ◽  
pp. 4238-4247 ◽  
Author(s):  
Rodrigo Ormazábal-Toledo ◽  
Sebastián Richter ◽  
Andrés Robles-Navarro ◽  
Boris Maulén ◽  
Ricardo A. Matute ◽  
...  
Keyword(s):  
Computational Study ◽  
Physical Factors ◽  
Meisenheimer Complexes

In this work we report a computational study about the aza-SNAr mechanism in fluorine- and chlorine-containing azines with the aim to unravel the physical factors that determine the reactivity patterns in these heterocycles towards propylamine.

Computational study of substituent effects on gas-phase stabilities of Meisenheimer complexes

2015 ◽  
Vol 93 (12) ◽  
pp. 1327-1334 ◽  
Author(s):  
Kazuhide Nakata ◽  
Mizue Fujio ◽  
Hans-Ullrich Siehl ◽  
Yuho Tsuno
Keyword(s):  
Gas Phase ◽  
Narrow Range ◽  
Computational Study ◽  
Substituent Effects ◽  
Orbital Interaction ◽  
Conjugation System ◽  
Isodesmic Reactions ◽  
Meisenheimer Complexes ◽  
Stabilization Energies ◽  
Respective Species

The total stabilization energies (TSEs) and anion stabilization energies (ASEs) of ring-substituted (X-) Meisenheimer complexes featuring two NO2 groups in the ring were determined using appropriate isodesmic reactions. The structures and energies of respective species were calculated at the B3LYP/6–311+G(2d,p) level of theory. Ten series of substituent effects were examined by varying substituent Y, which is connected to the sp3 carbon of the ring. The substituent effects were successfully analyzed using an extended Yukawa–Tsuno equation, [Formula: see text]. The r− values for the TSEs were identical to those for the ASEs, whereas the s values for the TSEs were significantly different from those for the ASEs. This shows that the effect of neutral species contributes to the s values of the TSEs. The r− and s values for the ASEs of all Meisenheimer complexes were distributed in a narrow range because substituent Y was insulated from the π-conjugation system. The r− values were large and the s values were small. This shows that the r− and s values were independent of each other and that the extended three-term Yukawa–Tsuno equation was intrinsic for substituent-effect analyses of anions. Although the variation was not substantial, the change in the r− values was clearly explained by the orbital interaction between substituent Y and the π-conjugation system. The r− values exhibited a good correlation with the bond lengths between the ring and the 4-NO2 group among all Meisenheimer complexes and benzylic anions. These facts provide a physical meaning: the r− value is a parameter that reveals the degree of the additional π interactions between the electron-withdrawing substituents and the π-conjugation systems of the ring.

PENGARUH RADIO DAN TELEVISI TERHADAP PARTISIPASI MASYARAKAT DALAM PENJAGAAN LINGKUNGAN DAN ALAM SEKITAR BAGI TERWUJUDNYA PEMBANGUNAN BERKELANJUTAN

2019 ◽  
Vol 13 (2) ◽  
pp. 115-123
Author(s):  
Ratu Mutialela Caropeboka
Keyword(s):  
Cultural Change ◽  
Social Factors ◽  
Information Dissemination ◽  
Local Community ◽  
Social Economic ◽  
Physical Factors ◽  
Development Communication ◽  
Balanced Development ◽  
Television Broadcasting ◽  
Major Process

The environment is also called the natural environment is a phenomenon that forms around life rather than humans, either biotic or abiotic. The surrounding phenomenon that affects people is not limited to physical factors solely, on the contrary social factors play an important role to explain how human activity can affect the environment and the natural surroundings. The essence and falsafa of development is a change, growth and equity in all fields and dimensions to a better state. Development communication is part of a major process that requires social, economic, political and cultural change in line with the requirements of the local community. The simultaneous formulation of information dissemination carried out by radio, is no longer the only option of society, because the community has designed and determined what information they need. Television broadcasting has an influence on patterns of public action to model, imitate information gained through impressions. Community participation in safeguarding the environment to achieve harmonious and balanced development is the driving and driving force for social change to achieve sustainable development. Lingkungan disebut juga alam sekitar adalah fenomena yang wujud di sekeliling kehidupan daripada manusia,baik biotik ataupun abiotik. Fenomena sekeliling yang mempengaruhi manusia tidak terbatas kepada faktor fisikal semata-mata, sebaliknya faktor sosial turut berperanan penting bagi menerangkan bagaimana aktivitas manusia dapat mempengaruhi lingkungan dan alam sekitar. Hakikat dan Falasafah pembangunan ialah suatu perubahan, pertumbuhan dan pemerataan dalam segala bidang dan dimensinya menuju keadaan yang lebih baik. Komunikasi pembangunan merupakan bahagian dari proses besar yang menghendaki adanya perubahan sosial, ekonomi, politik dan budaya yang sejalan dengan persyaratan keperluan masyarakat lokal. Formula keserentakan penyebaran informasi yang dilakukan melalui radio, tidak lagi menjadi satu-satunya pilihan masyarakat, karena masyarakatlah telah merancang dan menentukan informasi apa yang mereka perlukan. Siaran televisi mempunyai pengaruh pada pola tindakan masyarakat untuk mencontoh, meniru informasi yang didapat melalui tayangan. Partisipasi masyarakat menjaga lingkungan untuk mewujudkan pembangunan yang serasi dan seimbang adalah penggerak dan pengarah bagi perubahan sosial untuk mewujudkan pembangunan yang berkelanjutan

Influence of physical factors and cultures of microorganisms on segmented polyurethane’s degradation

2016 ◽  
Vol 38 (3) ◽  
pp. 236-243
Author(s):  
L.V. Kobrina ◽  
◽  
V.V. Boiko ◽  
T.V. Dmitrieva ◽  
V.V. Bortnitsky ◽  
...  
Keyword(s):  
Physical Factors
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