# Infrared Matrix-Isolation and Theoretical Studies of the Reactions of Bis(benzene)chromium with Ozone

## TL;DR

Scientists used infrared spectroscopy and computer models to study how a chromium compound reacts with ozone, revealing new chemical products.

## Contribution

The study identifies a novel chromium-containing product and hydrogen ozonide formation through matrix-isolation and DFT calculations.

## Key findings

- Two new infrared peaks at 431 cm−1 and 792 cm−1 were observed upon reaction of Bz2Cr with ozone.
- The 792 cm−1 peak matches the antisymmetric stretch of a symmetric ozonide, likely H2O3.
- DFT calculations suggest the chromium product is BzCrBPCrBz with a calculated energy change of −52.13 kcal/mol.

## Abstract

Reactions of bis(benzene)chromium (Bz2Cr) and ozone (O3) were studied using low-temperature argon matrix-isolation infrared spectroscopy with supporting DFT calculations. When Bz2Cr and O3 were co-deposited, they reacted upon matrix deposition to produce two new prominent peaks in the infrared spectrum at 431 cm−1
and 792 cm−1. These peaks increased upon annealing the matrix to 35 K and decreased upon UV irradiation at λ = 254 nm. The oxygen-18 and mixed oxygen-16,18 isotopic shift pattern of the peak at 792 cm−1
is consistent with the antisymmetric stretch of a symmetric ozonide species. DFT calculations of many possible ozonide products of this reaction were made. The formation of a hydrogen ozonide (H2O3) best fits the original peaks and the oxygen-18 isotope shift pattern. Energy considerations lead to the conclusion that the chromium-containing product of this reaction is the coupled product benzene-chromium-biphenyl-chromium-benzene (BzCrBPCrBz). 2Bz2Cr+O3→H2O3+BzCrBPCrBz, ∆Ecalc=−52.13kcal/mol.