A Study On The Aromaticity Of Azulene And Its Related Compounds

The global aromaticity of azulene and of its related compounds has been examined by the topological resonance energy(TRE)and magnetic resonance energy(MRE)methods.The local aromaticity was studied using bond resonance energy(BRE)and circuit resonance energy(CRE)methods.Moreover,the magnetic properties were studied employing the circuit current(CC)and ring current(RC)methods.Finally,our RC results were compared with the nucleus-independent chemical shift(NICS)values.The main points of this thesis are outlined as follows:In chapter 1 the origins and development of concepts related to aromaticity are presented.Several conventional indices of aromaticity,including geometric,energetic and magnetic indices were introduced and compared.We have described the history of synthesizing azulene and its construction.In chapter 2 the global aromaticity of azulene and azaazulene is examined by means of the TRE and MRE methods.The relationship between the aromaticity of the azulene isomers and the positions at which nitrogen atoms substitute themselves into the azulene skeleton has been discussed.The effect of nitrogen substitution on the azulane skeleton is investigated using the topological charge stabilization(TCS)rule.The local aromaticities are examined by the BRE and CRE methods.Our CC and RC results are then compared with the NICS results.We have identified a local aromaticity differential between the five-seven membered rings.We found that the seven-membered ring bonds which contain an –N= group exhibit lower local aromaticity than the five-membered ring bonds.In chapter 3 the global aromaticity of a diazulene is studied by means of the TRE and MRE methods.The local aromaticities are examined using the BRE and CRE methods.The relationship between the aromaticity of the diazulene isomers and the positions at which nitrogen atoms substitute themselves into the diazulene skeleton has been discussed.The effect of nitrogen substitution on the diazulane skeleton is investigated using the topological charge stabilization(TCS)rule.We have identified a local aromaticity differential between the five-seven membered rings.In chapter 4 the global aromaticity of azulene type compounds is studied by means of the TRE and MRE methods.The local aromaticities are examined using the BRE and CRE methods.The magnetic properties are also examined by the CC and RC methods.In chapter 5 the global aromaticity of azulenefurans and their derivatives is studied using the TRE and MRE methods.The local aromaticities are examined by the BRE and CRE methods.The magnetic properties are also examined by the CC and RC methods.We have identified a local aromaticity differential between the seven and five-membered rings.In chapter 6 the global aromaticity of azulene quinone is studied using the TRE and MRE methods.The local aromaticities are examined using the BRE and CRE methods.The magnetic properties are also examined by the CC and RC methods.In chapter 7 the global aromaticity of tropone is studied using the TRE and MRE methods.The differences in local aromaticity between the seven and six membered rings are examined by the BRE and CRE methods.The calculation results indicate that tropones can be stabilized primarily by the 6π-electronic system.In chapter 8 the relationship between the aromaticity of the azulene like compounds and the positions at which nitrogen atoms substitute themselves into the azulenelike skeleton has been discussed.The effect of nitrogen substitution on the azulanelike skeleton is investigated using the topological charge stabilization(TCS)rule.In chapter 9 the relationship between the aromaticity of the Tricyclopenta [c,d,f,h]compounds.The local aromaticities are examined by the BRE and CRE methods.The magnetic properties are also examined by the CC and RC methods.We have identified a local aromaticity differential between the seven and five-membered rings.