A Study On The Aromaticity Some Monocyclic Compounds

Aromaticity is one of the most important concepts in organic Chemistry. Themost widely used quantitative measures of the degree of aromaticity are energeticproperties (resonance energies), structural properties (nearly equal bond lengths in thering), and magnetic properties (such as ring current and magnetic susceptibilities). Inthis study, the aromaticity of monocyclic compounds compounds has been examinedby the topological resonance energy (TRE) and magnetic resonance energy (MRE)methods. The magnetic properties were studied employing the ring current (RC) andring current diamagnetic susceptibility (χG) methods. Finally，The results we obtainedwere compared with the results obtained by others who used the energetic methodASE (aromatic stabilization energy), PDI (Para-Delocalization Index), FLU(aromaticity fluctuation index), the geometric method HOMA (harmonic oscillatormodel of aromaticity) method, and the magnetic method NICS (nucleus-independentchemical shift).The main points of this thesis are outlined as follows:In chapter1the origins and development of concepts related to aromaticity arepresented. Several conventional indices of aromaticity, including geometric，energeticand magnetic indices were introduced and compared. Their strengths and weaknesseshave been pointed out. Finally, the research significance of this paper is presented.In chapter2the aromaticity of azines was studied using the TRE, percentagetopological resonance energy (%TRE), and MRE methods. Our results we comparedwith the results obtained by others who used the HOMA and the NICS method. Themagnetic properties of azines are also examined using the RC and χGmethods.In chapter3the aromaticity of BN-substituted derivatives of benzene is studied bymeans of the TRE and MRE methods. Its magnetic properties are also examined usingthe RC and χGmethods. In chapter4the relative aromaticity pyrole, furane, thiophene, as well as that oftheir nitrogen-substituted derivatives was examined using the TRE, MRE, RC, and χGmethods. The results we obtained were compared with the results obtained by otherswho used the ASE, the HOMA, and the NICS (1) methods. The effect of nitrogenatoms on aromaticity after substitution has been discussed. Their magnetic propertiesare also examined using the RC and χGmethods. The relationship between theenergetic indices of aromaticity and magnetic indices of aromaticity of thesecompounds are analyzed.In chapter5the aromaticity of the exocyclic substituents of cyclopropene,cyclopentadiene, cycloheptatriene, and cyclononatetraiene are studied using the TREand MRE methods. Their magnetic properties are also examined by the RC and χGmethods.In chapter6the aromaticity of nine-membered heterocycles are studied usingthe TRE and MRE methods. Their magnetic properties are also examined by the RCand χGmethods.In chapter7the aromaticity of the tropylium ion and its mono-anddiheteroatomic derivatives are studied using the TRE and MRE methods. Theirmagnetic properties are also examined by the RC and χGmethods.In chapter8the aromaticity of polyphosphaphospholes are studied using the TREand MRE methods. Their magnetic properties are also examined by the RC and χGmethods.In chapter9the aromaticity of the perfluorination of benzene are studied usingthe TRE and MRE methods. The magnetic properties are also examined by the RCand χGmethods.In chapter10the aromaticity of eight-membered heterocycles are studied usingthe TRE and MRE methods. Their magnetic properties are also examined by the RCand χGmethods. In chapter11the aromaticity of neutral and dianionic [N] radialenes, oxocarbons,and thiocarbons are studied using the TRE and MRE methods. The magneticproperties are also examined by the RC and χGmethods.