Vibrational spectra and assignment for trans-3,4-dichlorocyclobutene. Revised assignment for the cis isomer

Rotational analysis of bands in the high-resolution infrared spectra of the three species of butadiene-1,4-d2; refinement of the assignments of the vibrational fundamentals

“…trans-3,4-Dichlorocyclobutene was prepared by anhydrous (Aldrich) Al 2 Cl 6 -catalyzed isomerization of cis-1,4-dichlorocyclobutene (Fluka) [16,17]. ttDClBDE was prepared by stereospecific isomerization of trans-3,4-dichlorocyclobutene heated in a glass bulb at 86°C for 3 h [18].…”