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Slow diffusion reactions of Ln3+ (Ln = Ce, Eu, Tb) ions, pyrazine, and the [W(CN)8]3– unit at 0 °C produced three discrete coordination compounds [Ln(H2O)5(CH3CN)2][W(CN)8]·0.5pyrazine·CH3CN·2H2O [Ln = Ce (1), Eu (2)] and [Tb(H2O)6(CH3CN)2][W(CN)8]·pyrazine·2CH3CN·3H2O (3). Single crystal X-ray diffraction analysis revealed that compounds 1 and 2 are isomorphous and adopt a rare centrosymmetric tetranuclear square unit, while compound 3 exhibits an ion-pair moiety, in which unique tetramer water clusters (H2O)4 are involved. The presence of different types of hydrogen-bonding interactions is responsible for the formation of three-dimensional supramolecular networks. The isolations of compounds 1–3 provide a further insight into the effect of temperatures on constructions and structures of the lanthanide(III)-pyrazine-octacyanotungstate(V) system.

The 1,1′-binaphthol-based dimers with p-phenylenebis(2-ethynyl) spacer, (+)-6 and (+)-2, were synthesized as chiral host compounds. 1H NMR, UV-vis, and fluorescent titration were used to evaluate the enantiomeric recognition abilities of the chiral host dimers toward the guest amine 7 and α-amino acid ester 8. The chiral BINOL-based dimers were found to have good enantiomeric recognition ability. The computer simulation of the host–guest complex molecules was carried out to describe the conformational changes of both naphthyl ring in the molecule of chiral host dimer after complexation with the guest molecule. Chirality 13:595–600, 2001. © 2001 Wiley-Liss, Inc.