Binding of cerium monoxide to annulenes and buckybowls.

The structural, electronic, bonding and magnetotropic properties of inclusion compounds formed upon interaction of cerium monoxide, CeO, with buckybowls (quadrannulene, C(31)H(16), corannulene, C(20)H(10) and sumanene, C(21)H(12)) have been investigated by DFT calculations. For the sake of comparison the structural, electronic, bonding and magnetotropic spectroscopic properties of related annulenes (cyclobutadiene, C(4)H(4), benzene, C(6)H(6) and cyclooctatetraene, C(8)H(8)) have also been investigated at the same level of theory. The metal-ligand bonding was characterized by Natural Bond Orbital (NBO) analysis. Despite the weak covalent interactions involving π···π*, δ···π* and φ···π* interactions in some adducts the larger part of the interaction energy is due to electrostatic and dispersion forces. The effect of the adduct formation on the structural and magnetotropic properties of the coordinated buckybowls and annulenes has also been explored by employing electronic structure computational techniques.