The Construction of an Apparatus Suitable for Matrix Isolation Studies of the Reactions of Small Molecules
This article describes the building of an apparatus designed for the matrix isolation technique, including the glassware, vacuum pumps, FUR spectrometer and cryogenic equipment involved. Matrix isolation is a technique where a rare gas is codeposited with reactant molecules on a base as a solid crystalline structure. The rare gas acts as a cage, preventing the diffusion of the reactant molecules. In this case, argon or xenon will be used as the matrix gas; and hydrazoic acid (HN3) and ethene (C2H4) will be the reactant molecules. The hydrazoic acid will be photolyzed to cause it to dissociate into molecular nitrogen and imidogen (NH): HN3 + hv -> NH + N2 (1) The matrix gas will be different depending on the electronic state of imidogen that is desired. If the singlet state is the objective, argon will be used; if it is the triplet state, xenon will be chosen. It is the goal of this experiment to test the hypothesis that the choice of the matrix gas can significantly alter the electronic state of the product imidogen via the "heavy-atom effect". This states that as the atomic number (weight) of the matrix gas increases, the chances of the occurrence of a forbidden transition also increases. In this research, the choice of xenon as the matrix gas may greatly increase the possibility of the spin forbidden transition 1HN3 -> 3N3H*. This excitedstate (represented by the asterisk) triplet is the species which dissociates to the triplet imidogen by a spin allowed process. Infrared spectroscopy will be used to determine the products of the reaction between imidogen and ethene. By looking at the spectra of the resulting compounds, it should be possible to determine whether the expected products of the photochemistry, aziridine for the singlet and aziridineand ethylamine for the triplet, have been formed.