Ship-in-a-bottle catalysts

In Fig. 2.1.6.6, the FTIR spectra of the Jacobsen ligand (a), the Jacobsen catalyst (bj, and the immobilized manganese salen complex in the cages of dealuminated faujasite zeolite (c) are compared. While spectra a and b have been measured using the standard KBr technique, the spectrum c of the ship in a bottle catalyst has been recorded using a self-supported wafer. The bands at wavenumbers 1466 cm, 1434 cm" , 1399 cm" and 1365 cm" in spectrum c can be assigned to the... 

Heinrichs, C. and Holderich, W.F. (1999) Novel zeolitic hosts for ship-in-a-bottle catalysts. Catal. Lett., 58, 75. 

The ship-in-a-bottle catalyst s main feature is the host-guest interaction which is neither covalent nor ionic. The guest is retained in the zeolite matrix by restrictive pore openings and will, in principle, keep all properties of the homogeneous complex in addition to the advantages offered by the heterogeneous system. 

In a variation on this theme, a bulky guanidine derivative, N,N,N"-tricyclohex-ylguanidine was encapsulated by assembly within the supercages of hydrophobic zeolite Y. The resulting ship-in-a-bottle catalyst was active in the aldol reaction of... 

Based on these recent developments ship-in-a-bottle catalysts appear to hold much promise, extending even to the design of chiial ships for enantioselective oxidation. 

Bulky guanidine derivatives/zeoUte Y can act as ship in a bottle catalysts... 

The porphyrin-like molecule ion phthalocyanine may be synthesised within the pores of a zeolite [137]. This is an example of ship in a bottle catalyst preparation. This type of catalyst is formed within the pore struc-... 

A major advantage of this ship in a bottle catalyst is that it does not decompose. The unsupported phthalocyanine degenerates by the interaction of two molecules. Clearly this cannot occur when the individual molecules are held apart by the zeolite framework. For this reason the phthalocyanine/zeolite catalyst is better than the phthalocyanine alone. When an equimolar mixture of cyclohexanone and cyclododecanone is introduced to the supported catalyst with iodosylbenzene present, the smaller ketone is oxidised in preference to the larger one. This phenomenon may be attributed to the sieving effect of the zeolite. The catalyst also shows some positional selectivity in the oxidation of octane [137]. 

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