5. A new chemical proof of the cyclic structure of glucosaminides

1940 ◽  
pp. 29 ◽  
Author(s):  
Albert Neuberger
Keyword(s):  
Cyclic Structure

scholarly journals Electronic Structure of n-Cycloparaphenylenes Directly Observed by Photoemission Spectroscopy

2021 ◽  
Author(s):  
Kaname Kanai ◽  
Takuya Inoue ◽  
Takaya Furuichi ◽  
Kaito Shinoda ◽  
Takashi Iwahashi ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electronic Structures ◽  
Photoemission Spectroscopy ◽  
Cyclic Structure ◽  
Visible Absorption ◽  
X Ray ◽  
Inverse Photoemission

A series of n-cycloparaphenylenes ([n]CPP) were studied by ultraviolet photoemission, inverse photoemission, ultraviolet-visible absorption, and X-ray photoemission spectroscopy to detect their unique electronic structures. [n]CPP has a cyclic structure in...

Cyclic Structure of Adenovirus DNA

Science ◽  
1965 ◽  
Vol 148 (3666) ◽  
pp. 100-102 ◽  
Author(s):  
K. O. Smith
Keyword(s):  
Cyclic Structure

Kinetics and Mechanism of the Aminolysis of S-Aryl O-Ethyl Dithiocarbonates in Acetonitrile

2004 ◽  
Vol 69 (12) ◽  
pp. 2174-2182 ◽  
Author(s):  
Hyuck Keun Oh ◽  
Ji Young Oh ◽  
Dae Dong Sung ◽  
Ikchoon Lee
Keyword(s):  
Transition State ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Interaction Constant ◽  
Kinetics And Mechanism ◽  
Cyclic Structure ◽  
Concerted Mechanism ◽  
Tetrahedral Intermediate ◽  
Kinetic Isotope ◽  
Hydrogen Bonded

The aminolysis of S-aryl O-ethyl dithiocarbonates with benzylamines are studied in acetonitrile at -25.0 °C. The βX (βnuc) values are in the range 0.67-0.77 with a negative cross-interaction constant, ρXZ = -0.24, which are interpreted to indicate a concerted mechanism. The kinetic isotope effects involving deuterated benzylamine nucleophiles (XC6H4CH2ND2) are large, kH/kD = 1.41-1.97, suggesting that the N-H(D) bond is partially broken in the transition state by forming a hydrogen-bonded four-center cyclic structure. The concerted mechanism is enforced by the strong push provided by the EtO group which enhances the nucleofugalities of both benzylamine and arenethiolate from the putative zwitterionic tetrahedral intermediate.

STUDY OF IRON–CARBON MIXED CLUSTERS FeCn (n=2−5): A POSSIBLE LINEAR-TO-CYCLIC TRANSITION FROM FeC3 TO FeC4

1996 ◽  
Vol 03 (01) ◽  
pp. 423-427 ◽  
Author(s):  
LAI-SHENG WANG
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cluster Size ◽  
Structural Transition ◽  
Carbon Clusters ◽  
Cyclic Structure ◽  
Cyclic Transition ◽  
Pure Carbon ◽  
Cyclic Isomer ◽  
Anion Photoelectron Spectroscopy ◽  
Mixed Clusters

Small Fe/C mixed clusters, [Formula: see text], are studied by anion photoelectron spectroscopy at 3.49-eV photon energy. The spectra of [Formula: see text] and [Formula: see text] show well-resolved features and are consistent with linear-to-linear detachment transitions. The [Formula: see text] spectrum is quite broad, suggesting large geometry change from the anion to the neutral. Since [Formula: see text] is known to be linear, our data suggest that neutral FeC4 may have a cyclic structure. The spectrum of [Formula: see text] exhibits both sharp and broad features, consistent with the existence of both a linear and a cyclic isomer. A linear-to-cyclic structural transition is thus suggested to take place for the neutral FeCn clusters from n=3−4; for n<4 they are linear and for n≥4 they can be both linear and cyclic. This is similar to the linear-to-cyclic transition occurring for pure carbon clusters from n=9−10 (Ref. 10) but at a much smaller cluster size due to the presence of the Fe atom.

scholarly journals Optically active distorted cyclic triptycenes: chiral stationary phases for HPLC

RSC Advances ◽  
2018 ◽  
Vol 8 (37) ◽  
pp. 20483-20487 ◽  
Author(s):  
Tomoyuki Ikai ◽  
Naoya Nagata ◽  
Seiya Awata ◽  
Yuya Wada ◽  
Katsuhiro Maeda ◽  
...  
Keyword(s):  
Stationary Phases ◽  
Chiral Stationary Phases ◽  
Optically Active ◽  
Cyclic Structure ◽  
Chiral Compounds ◽  
Axially Chiral

We have succeeded in developing triptycene-based chiral stationary phases with a distorted cyclic structure, which can resolve a series of axially chiral compounds.

STRATEGIES FOR CALCULATING PERSIMMETRIC CYCLIC QUASI-ORTHOGONAL MATRICES AS THE BASIS OF CODES

2020 ◽  
Author(s):  
В.А. НЕНАШЕВ ◽  
Е.К. ГРИГОРЬЕВ ◽  
А.М. СЕРГЕЕВ ◽  
Е.В. САМОХИНА
Keyword(s):  
Communication Channels ◽  
Software Implementation ◽  
Cyclic Structure ◽  
Signal Modulation ◽  
Orthogonal Matrices ◽  
Modulation Codes ◽  
Correlation Reception

Выделяется циркулянт как основная циклическая структура квазиортогональных матриц, используемых в качестве основы для создания кодов модуляции сигналов в каналах связи с корреляционным приемом. Рассматриваются три стратегии вычисления персимметричных циклических квазиортогональных матриц и приводятся характеристики их программной реализации. This article highlights the circulant as the main cyclic structure of quasi-orthogonal matrices used as a basis for creating signal modulation codes in communication channels with correlation reception. Three strategies for computing persymmetric cyclic quasi-orthogonal matrices are considered and the characteristics of their software implementation are given.

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