Photoisomerization of IC3N — An experimental and theoretical study

Abstract

J o u r n a l P r e-p r o o f Highlights  VUV photolysis of IC3N in argon matrix leads to IC2NC and ICNC2 isomers  IRC calculations show reaction paths leading to discovered isomers  IC3N ions and radical are not formed in detectable amounts for the IR absorption ABSTRACT: Here we present the results of a joint spectroscopic and quantum chemical study on the photochemistry of 3-iodo-2-propynenitrile (iodocyanoacetylene, IC3N). Vacuum-UV photolysis of the compound isolated in solid argon was explored. Calculations, carried out at the DFT and/or coupled-cluster level of theory, provided essential data concerning the thermodynamic stabilities, vibrational and electronic energy levels, ionization potentials, and electron affinities of IC3N-stoichiometry isomers and ions. The photochemical formation of thus far unknown species IC2NC and ICNC2 has been evidenced by the experiment and rationalized based on a detailed theoretical approach, involving the excited-state potential energy surfaces.

Vibrational Spectrum of ‘3-iodo-2-propynenitrile (IC3N)’ from accurate CCSD(T)-F12b/MP2-F12 potential energy surface

“…Among these, the first member of the series, and the simplest one, namely halogeno-propynenitrile, has been the subject of both infrared (IR) [1][2][3][4][5] and Raman [6] measurements. Recently, a joint experimental and theoretical work by Guzik et al [7] studied the photoisomerization of IC 3 N linear molecule widely known as iodo-cyanoacetylene or 3-iodo-2 propynenitrile. This molecule is the halogenated analogue of HC 3 N molecule extensively studied in the ion-molecule chemistry in Titan's ionosphere.…”