A Nitrogen Doped Asymmetric Phenalenyl with Zwitterionic Ground State

2021 ◽  
Author(s):  
Fang Miao ◽  
Hanjiao Chen ◽  
Sergio Moles Quintero ◽  
Guodong Xue ◽  
Juan Casado Cordón ◽  
...  
Keyword(s):  
Ground State ◽  
Negative Charge ◽  
Nitrogen Doped ◽  
Planar Configuration

Herein, an asymmetric N-doped phenalenyl compound (BTAP) was firstly synthesized and carefully studied. BTAP discloses a planar configuration and an unexpected zwitterionic ground state with the negative charge delocalized around...

scholarly journals A comparative study of the photochemistry of biphenyl adsorbed on cellulose and silicalite

2004 ◽  
Vol 6 (4) ◽  
pp. 193-198 ◽  
Author(s):  
J. P. Da Silva ◽  
L. F. Vieira Ferreira
Keyword(s):  
Ground State ◽  
Diffuse Reflectance ◽  
Solid Support ◽  
Ground State Absorption ◽  
Solid Supports ◽  
Time Resolved ◽  
Planar Configuration ◽  
Degradation Analysis ◽  
Photochemical Behaviour ◽  
Product Degradation

The photochemistry of biphenyl (BP) was studied on two model solid supports, silicalite and cellulose, using time resolved diffuse reflectance techniques and product degradation analysis. The results showed that the photochemical behaviour of BP depends on the solid support. Ground state absorption spectra indicated a near planar configuration in the ground state. BP triplet state was the only species detected on cellulose, while the radical cation(BP•+)was observed in silicalite. BP is relatively stable in both supports. Prolonged irradiations in cellulose lead to the formation of the three monohydroxybiphenyls, while in silicalite photooxidation products prevailed.

STRUCTURE AND STABILITY OF MONOCYCLIC $({\rm CH})_{4-n} ({\rm BL})_{n}^{2-}$(L = CO, N2, CS) DIANIONS AND THEIR DILITHIUM COMPLEXES

2008 ◽  
Vol 07 (04) ◽  
pp. 595-606
Author(s):  
HAI-SHUN WU ◽  
XIAO-FANG QIN ◽  
HAIJUN JIAO
Keyword(s):  
Ground State ◽  
Negative Charge ◽  
Chemical Shifts ◽  
Ground States ◽  
Membered Ring ◽  
Triplet States ◽  
Structure And Stability ◽  
Ring Carbon ◽  
Carbon Centers ◽  
Electrostatic Stabilization

Structure and stability of monocyclic [Formula: see text] dianions ( L = CO , N 2, CS ) with 6π-electrons, which are isolobal with cyclobutadiene dianion [Formula: see text], have been investigated at the B3LYP and CCSD(T) levels of theory. ( CH )3( BL )2- have non-planar singlet ground states. [Formula: see text] have planar singlet ground states, while [Formula: see text] isomers have folded four-membered central rings. Both [Formula: see text] and [Formula: see text] have planar ground states, the ground state of [Formula: see text] has a six-membered ring with two bridging and one terminal CS. Both [Formula: see text] and [Formula: see text] have reduced aromaticity compared to [Formula: see text] as indicated by the less negative nucleus independent chemical shifts (NICS) values. The mono-, di- and trisubstituted ( CH )3( BL )2-, [Formula: see text], and [Formula: see text] also have reduced aromaticity, while the 1,3-substituted [Formula: see text] have positive NICS values due to the localization of the negative charge at the ring carbon centers. In addition, the electrostatic stabilization of Li + in favor of the singlet or triplet states depends on the nature of their structures.

The Magnetism of DNA Molecular Materials

2011 ◽  
Vol 306-307 ◽  
pp. 46-49
Author(s):  
Yong Juan Wang ◽  
Jie Cheng ◽  
Xian Fang Yue ◽  
De Sheng Liu
Keyword(s):  
Molecular Structure ◽  
Magnetic Property ◽  
Metastable State ◽  
Ground State ◽  
Magnetic Moments ◽  
Dna Bases ◽  
Molecular Materials ◽  
Planar Configuration

In this paper, the atomic magnetic moments and spin-splittings of the six-member ring N2C4 cluster with planar and folding configurations in DNA bases are studied, respectively. The results show that the surprising interplay between the molecular structure and their magnetic property. In the planar configuration, the cluster exhibits antiferromagnetism and ferromagnetism in the ground state and metastable state, respectively. In the folding configuration, it exhibits antiferromagnetism and ferrimagnetism in the ground state and metastable state, respectively.

scholarly journals Ground-state oxygen holes and the metal–insulator transition in the negative charge-transfer rare-earth nickelates

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Valentina Bisogni ◽  
Sara Catalano ◽  
Robert J. Green ◽  
Marta Gibert ◽  
Raoul Scherwitzl ◽  
...  
Keyword(s):  
Rare Earth ◽  
Charge Transfer ◽  
Ground State ◽  
Negative Charge ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

Electronic Raman Studies of Shallow Donors in Silicon Carbide

2006 ◽  
Vol 527-529 ◽  
pp. 579-584 ◽  
Author(s):  
Roland Püsche ◽  
Martin Hundhausen ◽  
Lothar Ley ◽  
Kurt Semmelroth ◽  
Gerhard Pensl ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Raman Scattering ◽  
Ground State ◽  
Electronic Transitions ◽  
Nitrogen And Phosphorus ◽  
Nitrogen Doped ◽  
Electronic Raman Scattering ◽  
Doped Silicon ◽  
Donor States ◽  
Increasing Temperature

We study electronic Raman scattering of phosphorus and nitrogen doped silicon carbide (SiC) as a function of temperature in the range 7K < T < 300K. We observe a series of peaks in the Raman spectra which we assign to electronic transitions at nitrogen and phosphorus donors on different lattice sites. These transitions are identified as valley orbit transitions of the 1s donor ground state. From the polarization dependence of the observed peaks, we find that all electronic Raman signals have E2-symmetry of C6v for the hexagonal polytypes (6H-SiC and 4H-SiC) and E-symmetry of C3v for 15R-SiC. We find a reduction of the intensities of all valley-orbit Raman signals with increasing temperature and ascribe this reduction to the decreasing occupation of donor states.

Electronic structure of graphene nanoribbons doped with nitrogen atoms: a theoretical insight

2015 ◽  
Vol 17 (16) ◽  
pp. 10608-10614 ◽  
Author(s):  
A. E. Torres ◽  
S. Fomine
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Graphene Nanoribbons ◽  
Ionization Potentials ◽  
Electron Affinities ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
Reorganization Energies ◽  
Theoretical Insight

Nitrogen doped graphene nanoribbons have multiconfigurational ground state. Doping affects cationic, not anionic states. Restricted methods underestimate ionization potentials, overestimate electron affinities, produce large errors for reorganization energies.

An unusual ground-state stabilization effect and origins of the alpha-effect in aminolyses of Y-substituted phenyl X-substituted benzoates

1998 ◽  
Vol 76 (6) ◽  
pp. 729-737 ◽  
Author(s):  
Ik-Hwan Um ◽  
Eun-Kyung Chung ◽  
So-Mi Lee
Keyword(s):  
Ground State ◽  
Negative Charge ◽  
Reaction Rates ◽  
Primary Amines ◽  
Bonding Interaction ◽  
Leaving Group ◽  
Hammett Correlation ◽  
Alpha Effect ◽  
Stabilization Effect ◽  
Electron Withdrawing Group

Second-order rate constants have been measured spectrophotometrically for the reactions of X-C6H4CO2C6H4-Y with a series of primary amines in H2O containing 20 mol% DMSO at 25.0 ± 0.1°C. The reactivity increases as the substituent (X and Y) becomes a stronger electron-withdrawing group. The sigma + constants give better Hammett correlation than sigma constants for the reactions of 4-nitrophenyl X-substituted benzoates with glycylglycine (glygly) and hydrazine (NH2NH2), indicating that the ground-state stabilization effect is unusually significant on the reaction rates. The reactions of X-C6H4CO2C6H4-Y with glygly and NH2NH2 appear to proceed through the same mechanism, but the degree of leaving-group departure and the negative charge developed in the acyl moiety at the rate-determining TS is considered to be more significant for the glygly system than the NH2NH2 system based on ßlg and rho X values. The magnitude of the alpha -effect is observed to be not always dependent on the ßnuc value but dependent on the electronic nature of the substituent X and Y, i.e., an electron-donating substituent increases the alpha -effect, while an electron-withdrawing one decreases the alpha -effect. The present study has led to the conclusion that the ground-state effect is important for the reaction rates but it is not solely responsible for the alpha -effect, and the intramolecular H-bonding interactions (4) are proposed for the cause of the increasing or decreasing alpha -effect trends observed in the present system.Key words: alpha -effect, intramolecular H-bonding interaction, ground-state stabilization effect.

Renilla Bioluminescence: A Morphologic Approach to the Location of Photocytes

1974 ◽  
Vol 32 ◽  
pp. 208-209
Author(s):  
Ben O. Spurlock ◽  
Milton J. Cormier
Keyword(s):  
Excited State ◽  
Ground State ◽  
Molecular Basis ◽  
Light Emission ◽  
Chemical Basis ◽  
Electronic Excited State ◽  
Colonial Form ◽  
The Common ◽  
Eighteenth And Nineteenth Centuries ◽  
Catalyzed Oxidation

The phenomenon of bioluminescence has fascinated layman and scientist alike for many centuries. During the eighteenth and nineteenth centuries a number of observations were reported on the physiology of bioluminescence in Renilla, the common sea pansy. More recently biochemists have directed their attention to the molecular basis of luminosity in this colonial form. These studies have centered primarily on defining the chemical basis for bioluminescence and its control. It is now established that bioluminescence in Renilla arises due to the luciferase-catalyzed oxidation of luciferin. This results in the creation of a product (oxyluciferin) in an electronic excited state. The transition of oxyluciferin from its excited state to the ground state leads to light emission.

The Fine Structure of Glycocalyx in Human Spermatozoa. A High Resolution Cytochemical Study

1973 ◽  
Vol 31 ◽  
pp. 640-641
Author(s):  
P. Hernández-Jáuregui ◽  
A. Sosa ◽  
A. González Angulo
Keyword(s):  
Negative Charge ◽  
Iron Hydroxide ◽  
Human Spermatozoa ◽  
Surface Coat ◽  
Cell Surfaces ◽  
Colloidal Iron ◽  
Cytochemical Study ◽  
Specific Permeability ◽  
Extracellular Glycoprotein ◽  
Mammalian Spermatozoa

Glycocalyx is the name given by Bennett to the extracellular glycoprotein coat present in some cell surfaces. It appears to play an important role in cell properties such as antigenicity, cell adhesivity, specific permeability, and ATP ase activity. In the sperm this coat can be directly related to such important phenomena as capacitation and fertilization. The presence of glycocalyx in invertebrate spermatozoa has already been demonstrated. Recently Yanagimachi et al. has determined the negative charges on sperm surfaces of mammalian spermatozoa including man, using colloidal iron hydroxide. No mention was made however of the outer surface coat as composed of substances other than those confering a negative charge. The purpose of this work was therefore to determine the presence of a glycocalyx in human spermatozoa using alcian blue and lanthanum staining.

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