Ring stacking interactions

Additionally, spiperone (25) binding can be rationalized using this model by noting that a Tyr-32 of the heavy chain is ideally oriented for a perpendicular ring stacking interaction with the spiperone phenyl ring. 

INTRAMOLECULAR HYDROPHOBIC AND AROMATIC-RING STACKING INTERACTIONS IN TERNARY COMPLEXES IN SOLUTION... 

Intramolecular hydrophobic interactions are closely related to the described aromatic-ring stacking interactions. The first such example was published in 1976(37) a hydrophobic interaction was shown to occur between the Cu and Zn " " complexes of 2,2 -bipyridyl and 1,10-phenanthroline with the trimethylsilyl moiety of the also coordinated 3-(trimethylsilyl)-l-propanesulfonate or 3-(trimethylsilyl)propionate(37,38), as well as with alkyl groups of other aliphatic carboxylates(35,38,39) then the attention was focussed on systems with amino acids(17,40). 

This catalyst induces preferential re facial attack on simple aldehydes, as indicated in Ligure 2.2. The enantioselectivity appears to involve the shielding of the si face by the indole ring through a ir-stacking interaction. 

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