The square-pyramidal 50e cluster Fe3Te2(CO)9 reacts with CpRh(CO)2 (Cp = η5-C5H5) to give a good yield of the heterometallic 52e cluster CpRhFe2Te2(CO)7. This heptacarbonyl undergoes Me3NO-induced decarbonylation to give two isomers of the hexacarbonyl CpRhFe2Te2(CO)6. Recarbonylation of CpRhFe2Te2(CO)6 formed the same heptacarbonyl in isomerically pure form. In contrast, addition of PPh3 to CpRhFe2Te2(CO)6 gave two isomers of CpRhFe2Te2(CO)6PPh3 that differ with regard to the placement of the PPh3 ligand on iron or rhodium. The iron-phosphine adduct undergoes chemically induced decarbonylation to CpRhFe2Te2(CO)5PPh3 while the rhodium-phosphine adduct resists decarbonylation. 125Te NMR spectroscopy has been used for structure elucidation. The 50e (nido) clusters Fe3Te2(CO)9, Fe3Te2(CO)8(PPh3), and CpMFe2Te2(CO)6 (two isomers each for M = Co, Rh) all absorb in the range 1123-1081 ppm downfleld of Me2Te. In dramatic contrast, the 52e (arachno) clusters Fe3Te2(CO)9(PPh3), CpMFe2Te2(CO) and CpRhFe2Te2(CO)6PPh3 all absorb in the range -825 to -973 ppm. PtFe2Te2(CO)6(PPh3)2, which has an arachno-like structure but a nido electron count (50e), absorbs in the arachno range.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry