X-Ray Crystallography The Ultimate Proof of Structure

By 1989, when the previous volume was published, all doubts concerning the structures of the three major and two minor p-terr-butylcalixarenes had been 

Murakami, H. Ohseto, F. Shinkai, S. Chem. Lett. 1992, 539. 

The problem of determining the pK values of water insoluble calixarenes has been addressed by Shinkai and coworkers, who used the tetramethylam-monium salts of 4-nitrophenol, 2,4-dinitrophenol, and 2,4,6-trinitrophenol (pic- 

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