Theoretical and spectroscopic studies on molecular structure and hydrogen bonding of 1,2-bis (monochloroacetyl) cyclopentadiene

► 1,2-Bis (monochloroacetyl) cyclopentadiene forms a short-strong H-bond. ► Formation of hydrogen bond is confirmed by experimental and theoretical methods. ► The H-bond is assisted by π-electron delocalization through the CP ring. ► The potential energy barrier for proton transfer in MCACP is low. ► The scaled theoretical frequencies are in good agreement with the experimental data.