The synthesis and characterisation of the first (?5-heptamethylindenyl)molybdenum complexes are reported. Reaction of Li[C9Me7] with Mo(CO)6 in refluxing THF readily forms Li[Mo(CO)3(?5-C9Me7)], which is shown to be a useful precursor in the formation of (carbonyl)(?5-heptamethylindenyl)molybdenum complexes. The compounds [MoI(CO)3(?5-C9Me7)] 3, [Mo(Me)(CO)3(?5-C9Me7)] 4 and [Mo(CO)2(?3-C3H5)(?5-C9Me7)] 5 have been prepared from this intermediate and characterised. Treatment of 3 with AgBF4 and MeC=CMe affords [Mo(CO)(MeC=CMe)2(?5-C9Me7)]BF4 6a; for this and the indenyl analogue, a new route to carbonyl-bis(alkyne)-molybdenum derivatives is demonstrated. Reaction of 3 with T1PF6 in MeCN forms the complex [Mo(MeCN)2(CO)2(?5-C9Me7)]PF6 7. Protonation of 5 in the presence of MeC=CMe, or reaction of 7 with the same acetylene, also yields 6 with appropriate counter anions. Single crystal X-ray diffraction studies of compounds 5 and 6a are reported.
- Crystal structure