Germylenes polyatomic

This section is devoted to the electronic spectra of germylenes, stannylenes and plumby-lenes carrying polyatomic substituents. The available data on the absorption maxima of these species are collected in Table 4, from which it can be seen that only stable polyatomic stannylenes and plumbylenes have been characterized by UV spectroscopy. 

C. Nature of Electronic Transitions in Polyatomic Germylenes, Stannylenes and Plumbylenes... 

The nature of substituent effects on the position of absorption maxima corresponding to n — p transition in polyatomic silylenes have been considered in detail in theoretical studies of Apeloig and coworkers126 128. Unfortunately, there is no similar study for germylenes, stannylenes or plumbylenes. However, the available experimental data show that the main conclusions obtained by Apeloig and coworkers are also applicable to polyatomic germylenes, stannylenes and plumbylenes. 

TABLE 4. Absorption maxima of polyatomic germylenes, stannylenes and plumbylenes... 

Frequencies assigned to the fundamental vibrations of the triatomic germylenes, stannylenes and plumbylenes are collected in Table 7 together with corresponding data on triatomic silylenes for comparison. The vibrational frequencies are sensitive to the environment of the molecule. Therefore, the most precise frequency values measured under each type of condition used (in the gas phase and in different low-temperature inert matrices) by different spectroscopic methods are shown in the table for each of the CAs. Nonfundamental frequencies of triatomic and observed frequencies of polyatomic germylenes, stannylenes and plumbylenes are listed in the text. 

The number of polyatomic germylenes, stannylenes and plumbylenes characterized by their vibrational spectra is still very limited. Only IR spectroscopy was used for this purpose. Unstable molecules were studied in low-temperature inert matrices. The stable germylenes, stannylenes and plumbylenes were treated by standard means. 

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