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The vibrational spectra of various gaseous $\pi$-bonded organometallic complexes and their corresponding hydrocarbon ligands have been recorded in the third overtone region $(\Delta \nu =4)$ using intracavity photoacoustic spectroscopy. The spectra of butadiene iron tricarbonyl, benzene chromium tricarbonyl and cycloheptatriene chromium tricarbonyl have been recorded and compared to the spectra of 1,3-butadiene, benzene and cycloheptatriene, respectively. The spectra of organometallic compounds were different from the spectra of the corresponding hydrocarbon ligands, except for the benzene complex. Some additional absorptions and shifts of the peak positions were observed. In previous $work1$ the third overtone spectra of cyclopentadiene and metallocenes were compared. Three additional blue-shifted transitions have been observed for ferrocene and related compounds (ruthenocene, acetylferrocene and cyclopentadienyl titanium trichloride) and assigned to the different combinations of C-H stretch and C-C stretches and C-H bends of the cyclopentadienyl ring. The comparison of our new observations and previous results will be made. We believe that these investigations will help to understand the influence of metal bonding to conjugated $\pi$-systems and explain the catalytic reactivity of organometallic complexes.