Pruikkonen, Sanni
(Helsingin yliopisto, 2021)
Stacking of antiaromatic molecules leads to enhanced stability and higher conductivity due to reversed antiarotmaticity. It has been shown that cyclophenes consisting of antiaromatic Ni(II) norrcorrole subunits have a vertical current-density flux between the two metal ions. The Ni(II) meso- substituted dibenzotetraaza[14]annulene complex fulfills the Hückel rule for being antiaromatic. Upon increasing the temperature above 13 K, the effective magnetic moment of solid state Ni(II) meso-substituted dibenzotetraaza[14]annulene changes from being diamagnet to paramagnetic. A suggested explanation for this is that there might be weak interaction between the Ni atoms. In this study the possibility of the
existence of vertical current-density flux between the two metal ions in the Ni(II) meso-substituted dibenzotetraaza[14]annulene is investigated. In addition, the effect of the Ni and N atoms in Ni(II) 1,5,9,13-tetraaza[16]annulene was studied by replacing Ni and Zn and N with O.
Electronic motion in molecules that are under the influence of a magnetic field is investigated computationally, since at present there is no routine experimental method for doing that. TURBOMOLE, the Gauge-including Magnetically Induced Currents method and Paraview were employed in this study for structure optimization of the molecules, calculation of current-density flux and current strength in the molecules and visualisation of the current-density pathways respectively. The results of this study does not show any current transport between the subunits in the Ni(II) meso-substituted dibenzotetraaza[14]annulene complex. Both the Ni(II) 1,5,9,13-tetraaza[16]annulene and the Zn(II) 1,5,9,13-tetraaza[16]annulene are aromatic but they were not stacked due to their distorted structure. The (2Z,7Z,10Z,14Z)-1,9-dioxa-5,13-diazacyclohexadeca-2,7,10,14-tetraene-5,13-diide complexes with either Zn(II) or Ni(II) were both non-aromatic as well as the Ni(II) (2Z,7Z,10Z,14Z)-1,9-dioxa-5,13-diazacyclohexadeca-2,7,10,14-tetraene-5,13-diide dimer.