[Studies on the infrared spectra of clusters containing O3MoS3, [Mo(x) (CO)y(O,S-C6H4-1,2)3FezLm]n- (x = 1,2 or 3, y = 0,3,7 or 4, z = 0 or 1, L = Cl, m = 0,2, n = 1 or 2) unit and the relationship between the spectra and their structures].

The IR spectra of clusters containing O3MoS3 Unit, (Et4N) Mo(O, S-C6H4-1,2)3, (Et4N)2Mo2(CO)3(O,S-C6H4-1,2)3, (Et4N)2Mo3(CO)7(O,S-C6H4-1,2)3 and (Et4N)2Mo2(CO)4(O,S-C6H4-1,2)3FeCl2 have been investigated. The characteristic frequencies, nu (Mo(n+)-OtR) (n = 4,5), nu (Mo(n+)-ObR) (n = 0,4), nu (Mo(n+)-StR) (n = 4,5), nu (Mo(n+)-SbR)(n = 0,1,4), nu (C = O), nu (Mo(n+)-C)(n = 0,1), delta (Mo(n+)-C-O)(n = 0,1), nu (Fe(2+)-ObR) and nu (Fe(2+)-Cl) were assigned by comparing the vibrational frequencies and structure parameters of them with that of Mo-Fe-S clusters. The influences of sigma donor abilities of ligands L(-OR, -SR) on nu (Mo-C) and nu (C = O) and the effect of Mo(n+)-->Mo4+ (n = 0,1) charge transfer on nu (Mo(4+)-ObR), nu (Mo(n+)-C) and nu (C = O) have been discussed. A partial oxidation of cluster 4 to [Mo2(CO)3(O,S-C6H4-1,2)3]- (5) have been inferred according to the information from the changes of IR spectra of cluster 4 in air with time and the existence of cluster 5 was also verified by NFAB-MS of cluster 4.