C. Foces-Foces, C. Fernández-castaño, R. M. Claramunt
Feb 1, 1999
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0
Influential Citations
3
Citations
Journal
Journal of inclusion phenomena and macrocyclic chemistry
Abstract
The structures of 1,4-bis(pyrazol-1'-yl)-2,3,5,6- tetrakis(3'',5''-dimethylpyrazol-1''-yl) benzene 1, its monohydrate, 1a, four 1 : 2 host : guest complexes, 1b–1e (acetic, propionic, pentanoic, and (±)-2-methyl butyric acids) and a di-picrate salt, 1f, have been determined by X-Ray analysis. In all complexes, in the salt and in the monohydrate compound, the host molecules are hydrogen bonded to two centrosymmetric related guests and to the water molecule which is disordered over two positions to mimic the inclusion complexes. In all compounds, the host exhibits Ci symmetry having the lone pair on the N(2) atom of each pyrazole pointing alternately upwards (u) and downwards (d) from the benzene ring. 1H and 13C NMR spectra of the free host 1 and of the complexes are consistent with the ududud conformation and the stoicheiometry of the inclusion compounds.