Conservation of El-Sayed’s Rules in the Photolysis of Phenyl Azide: Two Independent Decomposition Doorways for Alternate Direct Formation of Triplet and Singlet Phenylnitrene

Abstract

In the present work, we demonstrate that the formation of triplet and singlet phenylnitrene, when arises from the photodissociation of phenyl azide, fulfills El-Sayed's rules or the electronic angular momentum conservation law. It is shown that the singlet−triplet inversion of phenylnitrene via the vibronic coupling mechanism is not an effective process. In contrast, it is found that there exist two independent dissociation channels that yield alternatively singlet and triplet phenylnitrene. Therefore, a proposed mechanism that violates the angular momentum low is avoided. The clue of the photoreaction lies in the conjunction (energetic and spatial) of two crossing points in a very narrow region of the multidimensional space: (i) an intersystem crossing (ISC1) and (ii) a conical intersection (CI1). The geometrical separation between these two crossing geometries is only 0.016 Å measured in Cartesian coordinates, and the respective energy difference is 2 kcal/ mol. This work has been performed by application of the complete active space self-consistent field and multiconfigurational second-order perturbation method.

Chemically heterogeneous carbon dots enhanced cholesterol detection by MALDI TOF mass spectrometry

“…Adsorption energies were estimated using the expressions given by Thermodynamics Statistical with programs developed by the members of our research group [43,44]. The potential energy surfaces, which represent the formation of complexes between cholesterol and (N-CDs) have been modeled using a full linear interpolation method in internal coordinates [45][46][47][48][49][50]. Molecular geometries were analyzed by MOLDEN and MacMolPlt [51,52] software.…”

Nitrene formation is the first step of the thermal and photochemical decomposition reactions of organic azides

“…[4][5][6][7][8][9][10][11][12] Most of these applications as well as their exceptional reactivity arise from their ability to generate nitrene intermediates after N 2 extrusion. [13][14][15][16][17] Although organic azides are known for more than a century, 18 the decomposition reaction mechanism at an atomistic level is still under discussion. More specifically, there is a lack of agreement in the nature (concerted or asynchronous) of the so-called migration reaction in azides (Refs.…”

Insights into the Photodecomposition of Azidomethyl Methyl Sulfide: A S2/S1 Conical Intersection on Nitrene Potential Energy Surfaces Leading to the Formation of S-Methyl-N-sulfenylmethanimine

“…According to the calculated excitation energies, upon exposition to UV-radiation, the S 1 state of AMMS is populated (Table 3), the next state is out of the range of the source applied. Given that the first step in the decomposition of azide derivatives [39][40][41][42] usually gives the corresponding nitrene plus N 2 , we have built the linear interpolation [43][44][45][46][47][48][49][50][51] that connects the S 0 minimum of the azide derivative (M 0 , Figure 3(a)1)) with its dissociation products (Figure 3b). The potential energy profile depicted in this figure indicates that there would be two stationary points on the S 1 (1 1 A") surface around the Franck-Condon point, that is, a minimum and a transition state.…”