Vibrational spectra of lead alkyls and triethylbismuth

Abstract

A technique has been developed which permits the irradiation of lead alkyls and other unstable compounds with intense 4358-Å mercury light at so low temperatures that photochemical decomposition is negligible. More or less strongly exposed Raman spectra of tetramethyllead, trimethylethyllead, dimethyldiethyllead, methyltriethyllead, tetraethyllead, tetraethyllead-d 20 and triethylbismuth, all in the liquid state, were photographed with a three-prism glass spectrograph of reciprocal linear dispersion of 15 Å/mm at 4358 Å. A weakly exposed Raman spectrum of crystalline tetramethyllead was also obtained. To supplement available data, the infrared spectra in the region from 3 to 25 μ were obtained of liquid methyltriethyllead, tetraethyllead, and tetraethyllead-d 20, with the aid of a Perkin-Elmer Model 112 double-pass spectrometer. The assignments of vibrational fundamentals for tetramethyllead made by previous workers have been somewhat revised and extended. For the other alkyls, which undoubtedly exist in several conformations, a partial interpretation of the vibrational spectra has been made. Some striking peculiarities of the spectra are pointed out and discussed.