Matrix isolation and ab initio study of the hydrogen-bonded H2O2-CO complex.

The structure, energetics, and infrared spectrum of the H2O2-CO complex have been studied computationally with the use of ab initio calculations and experimentally by FTIR matrix isolation techniques. Computations predict two stable conformations for the H2O2-CO complex, both of which show almost linear hydrogen bonds between the subunits. The carbon-attached HOOH-CO complex is the lower-energy form, and it has an interaction energy of -9.0 kJmol(-1) at the CCSD(T)/6-311++G(3df,3pd)// MP2/6-311++G(3df,3pd) level. The higher-energy form, HOOH-OC, has an interaction energy of 4.7 kJmol(-1) at the same level of theory. Experimentally, only the lower-energy form, HOOH-CO, was observed in Ar, Kr, and Xe matrices, and the hydrogen bonding results in substantial perturbations of the observed vibrational modes of both complex subunits. UV photolysis of the complex species primarily produces a complex between water and carbon dioxide, but minor amounts of HCO and trans-HOCO were found as well.