Group 12 ligand characteristics

IR and Raman spectra of Zr(BH4)4 and Hf(BH4)4 have been assigned in terms of both 7 and T models, and assignments have been supported by deuterium isotopic substitution studies and normal coordinate analyses. The vibrational spectra have not provided unequivocal evidence for a choice between these two closely related point groups. However, the spectra strongly support a tridentate attachment of the BHT Ligands. Characteristic IR and Raman bands for Zr(BH4)4 and Hf(BH4)4 occur in the following frequency regions ... 

Essentially covalent two-centre M—C bonds occur with all except the most electropositive Group lA and IIA elements. Both main group and -block transition elements. Of covalent character with unsaturated organic ligands. Characteristic of -block transition elements. 

The assignments of infrared absorption bands are based on those observed for metal glycinates, since the structure of metal hydrazine carboxylates is reported to be similar to that of metal glycinates [6]. As the hydrazine carboxylate anion acts as a bidentate ligand, characteristic absorptions due to COO and N2H3 groups are observed and... 

Other Inorganics. Inorganic species in solution have been studied very effectively by Raman spectroscopy. Work in this area includes the investigation of coordination compounds (qv) of fluorine (qv) (40), the characterization of low dimensional materials (41) and coordinated ligands (42), and single-crystal studies (43). Several compilations of characteristic vibrational frequencies of main-group elements have been pubflshed to aid in the identification of these species (44,45). 

---