Rf block metal carbonyls

Table 24.3 Neutral, low-nuclearity (

In the unusually effective reducing medium of sodium-hexamethylphos-phoramide (HMPA), [Mn(CO)5] underwent facile reduction to form a golden yellow to yellow brown solution. On the basis mainly of derivative chemistry and infrared spectra, the major soluble component was formulated as Na3[Mn(CO)4] (14). Once this materia] was in hand it was evident that similar binary carbonyl trianions should be possible for other rf-block transition elements of odd atomic number. Since 1976, syntheses of mononuclear binary carbonyl trianions of V, Nb, Ta, Re, Co, Rh, and Ir have also been reported from this laboratory (vide infra). Because these substances contain transition metals in their lowest known oxidation states, they have often been referred to as superreduced species (15). 

Transition metal NMR has been surveyed by Kidd and Goodfellow, Kidd (nuclear shielding),Rinaldi, Levy, and Choppin (selected topics only), and Wehrli (quadrupolar nuclei). Monographs have appeared on V NMR primarily concerned with solution and solid state measurements, the chromium triad, and on the first transition series nuclei (Sc to Zn). Some generalizations on nuclear shielding in carbonyl complexes of V, Mn, and Nb have been reported. A comprehensive account on the complete block of the rf-metals has recently appeared. ... 

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