The Vibration Frequencies of [6] Cyclacenes (Linear, Angular and Angular-Chiral) Monoring Molecules

The (3n-6) vibration frequencies and ir-absorption intensities of [6] cyclacene (linear,angular and angular-chiral) monoring molecules were calculated applying density functionaltheory (dft) of the type (b3lyp) and a gaussian basis (6-311g) method. comparison of theresults showed that, similar to the polyaromatic hydrocarbons, the following relations hold:νsymmetricch str. > νasymmetric ch str. and, νsymmetric cc str. > ν asymmetric cc str. i. e., the following relation hold too,νsymmetric. cc str.(axial.) > νasymmetric. cc str.(axial) > νasymmetric. cc str. (circumferential) in the linear molecule, where axial are the vertical c-ca bonds (annular bonds) in the rings and circumferential c-cc are the outer ring bonds.the relation for the c-cstr. is reversed in the angular and the angular-chiral molecules, since the c-ca bonds are converted to c-cc bonds in the angular and angular-chiral cyclacenes. the results include the assignment of all puckering, breathing and clock-anticlockwise bending vibrations. they allow a comparative view of the charge density at the carbon atoms too.