Metal-metal and metal-ligand vibrational interaction in compounds of the Fe3EE '(CO)(9) (E, E ' = S, Se, Te) series and the low-frequency vibrational spectra of Co2FeS(CO)(9) and Os3S2(CO)(9)

The infrared and Raman spectra of the title compounds in the ca. 400-150 cm-1 region are reported. For the first time, detailed assignments are given for all of the features in this region for the first series of compounds. An attempt is made to extend to all of the modes the plastic cluster model of vibrational analysis, which is normally applied only to \u3bd(M-M) vibrations. While mixing occurs between \u3bd(Fe-Fe) and \u3bd(Fe-E), species containing Te posed particular problems; the reasons for this are discussed and give new insights into the plastic cluster model itself

The v(CO) vibrational spectra of planar transition metal carbonyl clusters

The \u3bd(CO) vibrational spectra of planar transition cluster carbonyls containing M(CO)4 groups are studied. It is possible to anticipate qualitatively, both for the infrared and Raman, the band intensity changes associated with increasing metallic nature of the cluster. These enable a unification of the band patterns shown by the species reported. As for (idealized) spherical clusters, the spherical harmonic model (SHM), suitably modified, becomes of more general applicability as cluster size increases, although for smaller species the tensor harmonic model (THM) makes a contribution