TUngsten complexes electronic spectra

In contrast to groups 4 and 5 transition metal complexes supported on silica, the treatment by H2 of W surface organometallic derivatives, namely, [(=SiO)W( C Bu)(CH2 Bu)2] and [(=SiO)2W( C Bu)(CH2 Bu)], mainly lead to sintering (re-formation of silanols and detection of W particles by transmission electron microscopy (TEM)) and the hydride is obtained only in minute amounts. On the other hand, [(AlsO)W( C Bu)(CH2 Bu)2] reacts with H2 to give tungsten hydride species [(AlsO)2W(H) .] with no evidence of sintering, as evidenced by the presence of W-H and Al-H bands in the IR spectrum (Scheme 46). ... 

The spectra of atoms can be measured by generating the atoms, for example, by vaporizing them into the gas phase. This can be difficult sometimes, especially for a substance like tungsten, which has a normal boiling point of 5660°C. However, many atoms and ions exist in the solid state as either metal complexes or as ionic crystals. Although the imposition of other chemical species around the atom or ion affects the spectrum (this is known as crystal field theory), the previous discussion provides the basis for understanding the electronic transitions of atoms and ions in compounds. 

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