Knowledge Bank

Nitrogen matrix IR spectroscopy and ab initio calculations of three distinct conformations of perfluoro-n-butane, $n-C1F10$, have recently been $reporteda$. We have measured the Fourier Transform microwave spectrum of the gauche conformer of perfluoro-n-butane and determined the C-C-C-C dihedral angle to be $\sim 51\circ$. This is in good agreement with the ab initio calculations of Albinsson and Michl that predicted dihedral angles of $54\circ ,95\circ$, and $165\circ$, for the gauche, ortho, and anti conformations, respectively. The search for the other conformations continues. In addition, the spectrum of the symmetric top isomer, perfluoroisobutane, has been observed.