نتایج جستجو برای: corannulene

تعداد نتایج: 137  

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2006
P Thaddeus

Over 130 molecules have been identified in the interstellar gas and circumstellar shells, the largest among them is a carbon chain with 13 atoms and molecular weight of 147 (twice that of the simplest amino acid glycine). The high reliability of astronomical identifications, as well as the fairly accurate quantitative analysis which can often be achieved, is emphasized. Glycine itself has been ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
Arthur J Olson Yunfeng H E Hu Ehud Keinan

Stable structures of icosahedral symmetry can serve numerous functional roles, including chemical microencapsulation and delivery of drugs and biomolecules, epitope presentation to allow for an efficient immunization process, synthesis of nanoparticles of uniform size, observation of encapsulated reactive intermediates, formation of structural elements for supramolecular constructs, and molecul...

Journal: :Physical chemistry chemical physics : PCCP 2012
Patxi García-Novo Alba Campo-Cacharrón Enrique M Cabaleiro-Lago Jesús Rodríguez-Otero

Complexes formed by anions and substituted molecular bowls were studied by means of computational methods. The bowls consisted of corannulene molecules substituted with five or ten F, Cl, or CN groups, whereas Cl(-), Br(-) and BF(4)(-) were the anions considered. Substitution with F, Cl and CN hardly affects the geometry of the bowl, but produces an inversion of the molecular electrostatic pote...

Journal: :Physical chemistry chemical physics : PCCP 2013
Weiqi Li Xin Zhou Wei Quan Tian Xiudong Sun

How to achieve maximum nonlinear optical (NLO) properties from the molecular to the macro block is very crucial to the development of nonlinear optical materials, which is the impetus of the present work. Buckybowls present large first hyperpolarizability ascribed to noncentrosymmetric charge distribution due to the curved shape of the system. The role of their packing pattern in maximizing the...

Journal: :Physical chemistry chemical physics : PCCP 2009
Erik I Tellgren Trygve Helgaker Alessandro Soncini

By means of non-perturbative ab initio calculations, it is shown that paramagnetic closed-shell molecules are characterized by a strongly non-linear magnetic response, whose main feature consists of a paramagnetic-to-diamagnetic transition in a strong magnetic field. The physical origin of this phenomenon is rationalised on the basis of an analytical model based on molecular orbital theory. For...

2012
Gregory T. McCandless Andrzej Sygula Peter W. Rabideau Steven F. Watkins Frank R. Fronczek

The title compound, C(36)H(24)O(6)·CH(2)Cl(2), is a dimer of two essentially planar (r.m.s., deviations of fitted plane of 14 pyracene C atoms = 0.0539 and 0.0543 Å) tetra-cyclic pyracene frameworks (each with four methyl groups and three carbonyl groups on the peripheral carbon atoms) twisted along a central C=C bond with an angle of 50.78 (3)° at 90 K. There are notably long Csp(2)-Csp(2) bon...

ژورنال: شیمی کاربردی 2017

در دودهه ی اخیر، شاخص جابجایی شیمیایی مستقل هسته ای (NICS) در بسیاری از مقالات برای سنجش میزان آروماتیسیته ترکیبات آلی و معدنی استفاده شده است. در این پژوهش خصلت آروماتیکی، غیر­آروماتیکی و ضد­آروماتیکی در حلقه­های مختلف نانوساختار­های کاسه­ایشکل کورونن[1] (C24H12)، کورانولن[2] (C20H10)، سومانن[3] (C21H12) و سیرکیومتریندن[4] (C36H12) که زیرساخت­های فولرن (C60) می باشند، با استفاده از این شاخص بر...

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