Study of the structure and excitation properties of polyalkylene Cyclo12 carbon

Polyalkylene cyclo[12] carbon (abbreviated: Cy12 carbon) has a unique structure and its bonding properties, vibrational spectra and excitation properties have been explored by quantum chemical methods. The bond order analysis and molecular orbital analysis show that this sp hybridized all-carbon cyclo exhibits a C–C “alternating long bond-short bond” planar structure with C_6h symmetry and two sets of in-plane (in-πMOs) and out-of-plane (out-πMOs) orbitals; After MPI (molecular polarity index) index calculation, Cy12 carbon showed significant non-polar; the vibration analysis shows that most of the vibrations are symmetrically forbidden and doubly degenerate, with strong in-plane stretching vibrations and vibrations perpendicular to the plane appear in the low-frequency region. The excited state analysis reveals two detectable absorption bands of π-π* transitioned with the strongest absorption peak located at 164.5 nm from two degenerate excited states (S35 and S36), corresponding to the electronically excited processes of maximum absorption with πinMOs-πin*MOs, πinMOs-πout*MOs, πoutMOs-πin*MOs and πoutMOs- πout*MOs with mixed characteristics.