(C5Me5)2NbBH4, a new reagent for the synthesis of Ru and Co carbonyl clusters with interstitial boron or carbon

The reaction Of CP*2NbBH4 (Cp* = eta 5-C5Me5) With Ru-3(CO)(12) gave a mixture of compounds, from which only [CP*Nb-2(CO)(2)](2)[Ru-6(CO)(16)C] (1) could be characterized by spectroscopic and crystallographic methods. B-11 NMR spectroscopy proved that interstitial boron may be present in other Ru-6 clusters, but these compounds did not crystallize. The reaction Of CP*2NbBH4 with CO2(CO)8 gave among others the salts [CP*Nb-2(CO)(2)](2)[Co-6(CO)(15)C] (4) and [CP*Nb-2(CO)(2)](3)[Co-13(CO)(24)C-2] (5), which were examined by X-ray diffraction studies. The true nature of the interstitial atoms in 5 was deduced from electrochemical investigations, which reveal similar redox properties as for the already known [Co-13(CO)(24)C-2](3-) anion. (c) 2005 Elsevier B.V. All rights reserved.