| Abstract
| - The inclusion compounds formed between β-cyclodextrin (β-CD) and the tetrafluoroboratesalts [Cp‘Mo(η4-C6H8)(CO)2][BF4] and the neutral derivatives Cp‘Mo(η3-C6H7)(CO)2 [Cp‘ =Cp (η5-C5H5), Ind (η5-C9H7)] were studied by means of elemental analysis, FTIR spectroscopy,thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), and magic-angle spinning(MAS) NMR (13C, 11B). Additional information concerning the possible structure of theinclusion compounds was obtained from ab initio calculations using a two-layer approximation. The cationic and neutral η5-cyclopentadienyl analogues form stable two-to-one (host-to-guest) channel-type inclusion compounds in a crystalline state. By contrast, the η5-indenylanalogues form only weak complexes with β-CD and it is evident that the organometallicguests are easily liberated from the host cavities. The ab initio calculations revealed thatthe steric hindrance arising from the presence of the indenyl ligand is a possible explanationfor the experimentally observed lower stability of these compounds.
- The dicarbonyl molybdenum complexes [CpMo(η4-C6H8)(CO)2][BF4] and CpMo(η3-C6H7)(CO)2 react with β-cyclodextrin to give stable 2:1 (host to guest) channel-type inclusion compounds in a crystalline state. By contrast, the corresponding η5-indenyl analogues [IndMo(η4-C6H8)(CO)2][BF4] and IndMo(η3-C6H7)(CO)2 form only weak complexes with β-CD and it is evident that the organometallic guests are easily liberated from the host cavities. Ab initio calculations provide valuable insight into the possible inclusion geometries.
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