scholarly journals Starphenes and Phenes: Structures and Properties

2019 ◽  
Vol 01 (01) ◽  
pp. 001-018 ◽  
Author(s):  
Elias C. Rüdiger ◽  
Matthias Müller ◽  
Jan Freudenberg ◽  
Uwe H. F. Bunz

Acenes have been known for a long time but their larger congeners, starphenes and phenes, have only been recently accessible as processable and characterizable derivatives. In this personalized review, we delineate the synthetic approach developed by our group over the last four years. Nickel-mediated Yamamoto coupling of ortho-dibromoacenes generates cyclotrimers. If performed in a shotgun approach, i.e. with substituted 2,3-dibromotetracene or -pentacene in the presence of ortho-dibromobenzene or ortho-dibromoveratrole, trimeric phenes and tetramers would result. Cyclotrimers formed by a pentacenylene and two phenylenes are formally dibenzo[a,c]hexacenes. A direct way to obtain these species is to employ Stille coupling of a dimethylstannafluorene with 2,3-dibromoacenes. If tetrabromoanthracenes or tetrabromopentacenes are fed into this process, tetrabenzopentacene and tetrabenzoheptacenes are easily accessible. Optical and quantum-chemical characterizations provide insight into the electronic situation and aromaticity of these species.

2019 ◽  
Vol 26 (8) ◽  
pp. 1311-1327 ◽  
Author(s):  
Pala Rajasekharreddy ◽  
Chao Huang ◽  
Siddhardha Busi ◽  
Jobina Rajkumari ◽  
Ming-Hong Tai ◽  
...  

With the emergence of nanotechnology, new methods have been developed for engineering various nanoparticles for biomedical applications. Nanotheranostics is a burgeoning research field with tremendous prospects for the improvement of diagnosis and treatment of various cancers. However, the development of biocompatible and efficient drug/gene delivery theranostic systems still remains a challenge. Green synthetic approach of nanoparticles with low capital and operating expenses, reduced environmental pollution and better biocompatibility and stability is a latest and novel field, which is advantageous over chemical or physical nanoparticle synthesis methods. In this article, we summarize the recent research progresses related to green synthesized nanoparticles for cancer theranostic applications, and we also conclude with a look at the current challenges and insight into the future directions based on recent developments in these areas.


2020 ◽  
Vol 700 ◽  
pp. 121639 ◽  
Author(s):  
Roman Tsyshevsky ◽  
Ashley R. Head ◽  
Lena Trotochaud ◽  
Hendrik Bluhm ◽  
Maija M. Kuklja

2016 ◽  
Vol 39 (3-4) ◽  
Author(s):  
Sandeep Pokharia ◽  
Rachana Joshi ◽  
Mamta Pokharia ◽  
Swatantra Kumar Yadav ◽  
Hirdyesh Mishra

AbstractThe quantum-chemical calculations based on density functional theory (DFT) have been performed on the diphenyltin(IV) derivative of glycyl-phenylalanine (H


Author(s):  
Aldona Kipāne

The article gives an insight into criminological problems of bullying in school phenomena. Although the term “bullying” is a modern word, such behaviour has been known for a long time. Bullying is a manifestation of violent behaviour, which threatens the victim's health and safety. The aim of this article is to describe and analyse bullying as a form of expression of violence, showing the criminological aspects of this phenomenon. To achieve the aim of the article the following tasks are defined: to provide the theoretical and practical framework of the research phenomenon, to study and evaluate certain elements of the criminological characterization of the bullying: the description of a victim and a perpetrator, the evaluation of factors and directions of prevention. Theoretical analysis methods such as deconstruction, descriptive and complex analysis, and empirical research methods – document analysis, comparison and compilation were employed in this study.


2021 ◽  
Vol 3 (1) ◽  
pp. 40-77
Author(s):  
Kamau Wango

Artistic commemoration of leaders and other iconic personalities has been in existence for centuries. Statues in particular have been used as a fitting avenue for the commemoration of political leaders and other luminaries in many fields. The premise upon which statues are made is that the subjects featured initiated and attained, in their lifetimes, concrete achievements that significantly impacted upon the lives of their fellow human beings. Other criteria for commemoration include proven integrity, dedication and selflessness in the service of the country and citizens. Statues as an integral part of public art have often generated substantial controversy on various fronts in many countries. Some of these gravitate around issues such as disputed likeness, queries about the fundamental achievements cited of the subject, at times open protests on the actions, character and integrity of the subject as well as the location of the statues. Other areas of contention include the implication of the presence of statues upon the political psyche of the country and their long-time impact on history, the youth and posterity. This paper examines the extent to which African countries have embraced this mode of artistic rendition to commemorate African political leaders in a way that is commensurate to their achievements. It is outside the scope of this paper to delve into the intricate web of back-and-forth arguments about the ‘concreteness’ of the legacies of the featured leaders who are mainly founding political figures of the respective countries. The paper, however, analyses the artistic essence of the selected statues in terms of their visual impact and whether they are indeed useful in articulating the legacies of the subjects and further, whether they ultimately bear ‘enduring visual value’ that spurs conversation and insight into these legacies. Statues must, at the very least, spur debate and conversation into the legacy of the featured subject. It becomes a form of constant interrogation as history itself takes its course; controversy is not necessarily a negative occurrence since it forms part of this discourse. The concept of immortalization, which is what initiators of statues often hope for is much harder to achieve and difficult to define. The paper examines 20 statues of African political leaders in different African Countries.


ACS Catalysis ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 8006-8013 ◽  
Author(s):  
Minh Nguyen Vo ◽  
Yasemin Basdogan ◽  
Bridget S. Derksen ◽  
Nico Proust ◽  
G. Adam Cox ◽  
...  

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