16005-17-7Relevant academic research and scientific papers
Molecular structure and infrared spectra of 3,4-dihydroxy-3-cyclobutene-1,2-dione; experimental matrix isolation and theoretical Hartree-Fock and post Hartree-Fock study
Rostkowska, Hanna,Nowak, Maciej J.,Lapinski, Leszek,Smith, Dayle,Adamowicz, Ludwik
, p. 959 - 968 (1997)
The infrared spectra of 3,4-dihydroxy-3-cyclobutene-1,2-dione (squaric acid) isolated in low-temperature Ar and N2 matrices are reported. The comparison of the experimental spectra with those theoretically calculated at HF/6-31 + + G**, MP2/6-31G** and DFT(B3-LYP)/6-31 + +G** levels shows that the molecules of the compound isolated in low-temperature matrix adopt the structure with C2v symmetry. This structure is different from the one which was found in the crystal. Theoretical calculations of relative energies of C2v and Cs structures predict the C2v conformation to be lower in energy by 8 kJ mol-1. Good agreement between the experimental and theoretical spectra allowed for a reliable assignment of the observed IR absorption bands.
