Single-photon ionization induced C–C or C–N bond formation in pyrrole clusters

Abstract

The formation of photodimers of nitrogen heterocyclic compounds (NHCs) could partially explain DNA damage due to radiation. Pyrrole and its derivatives, as major components of DNA, are used to understand...

Single-Photon Ionization Induced New Covalent Bond Formation in Acrylonitrile(AN)–Pyrrole(Py) Clusters

“…Considering the structural features, the dissociation of (AN-Py 2 ) + is more likely to produce (Py) 2 + and will not have a large effect on the production of (AN-Py) + . Not only (AN-Py 2 ) + -III-( 1 + has also been proved in our previous report, 50 in which a CC structure is considered to be the primary product of (Py) 2 + . As a result, the more stable structure (AN-Py 2 ) + -I-(1) with the formation of a new C−C covalent bond is the dominant product after the (AN-Py 2 ) cluster is ionized by VUV light in the gas phase.…”

“…As a result, the more stable structure (AN-Py 2 ) + -I-(1) with the formation of a new C−C covalent bond is the dominant product after the (AN-Py 2 ) cluster is ionized by VUV light in the gas phase. Furthermore, with the addition of AN, the barriers to forming the covalent bonds shown in Figure 4 are lower compared to the equivalent ones for the formation of the covalently bonded structure (Py) 2 + that we discussed before, 50 indicating that the favored pathway could be the formation of (AN-Py 2 ) + -I-(1).…”

“…To determine whether the proton transfer and the formation of new covalent bonds can occur in the ion–molecule reaction of the (AN-Py 2 ) + cluster, IR spectra of the stable structures of (AN-Py 2 ) + were calculated and compared to the observed one. Based on the features of the most stable structures in (Py) 2 + and (AN-Py) + clusters mentioned above, 27 isomers of (AN-Py 2 ) + are found and can be classified into five types based on previous works on (Py) 2 + reported by Dopfer et al and our group . (1) (AN-Py 2 ) + -I, a new C–C covalent bond, is formed between two Py, with the additional AN attached to them via a H-bond.…”

“…In our previous studies, we reported that a new covalent bond was formed not only in AN 2 + clusters but also in (Py) 2 + clusters upon VUV single-photon ionization. To explore whether AN or Py is more likely to form a new covalent bond with another Py in the clusters, the structures and infrared spectra of the (AN-Py 2 ) clusters were investigated as follows.…”

“…The same computational method and basis set were used as in our previous study of (Py) 2 + and (Py) 3 + . 50 The calculated infrared spectra of the stable structures were all scaled by a scaling factor of 0.95.…”