Potential Applications of Q[n]-Based Coordination Complexes and Polymers - Supramolecular Assemblies of Cucurbit[n]urils with Metal Ions - page 91

Fig. 4.8 X-ray crystal structure of two compounds for the two isomorphous groups: a a complex
of Q[8] with cerium cations; b , c a Ce 3 + /Q[8] complex surrounded by six [CdCl 4 ] 2 − anions;

d a [CdCl 4 ] 2 − anion surrounded by three Ce 3 + /Q[8] complexes; e 2D network constructed of

Ce 3 + /Q[8] complexes and [CdCl 4 ] 2 − anions; f a sandwich constructed from two metal free Q[8]

molecules and a Ce 3 + /Q[8] complex which is surrounded by six [CdCl 4 ] 2 − anions; g , h an over-

all view of the stacking of Ce 3 + /Q[8] complexes and [CdCl 4 ] 2 − anions [ 13 ]

and Eu 3 + respectively, while the other group is characteristic of coordina-
tion of Q[8] molecules with the heavy lanthanide cations, such as Gd 3 + , Tb 3 + ,
Ho 3 + , Er 3 + , Tm 3 + , Yb 3 + , and Lu 3 + respectively. A complex consisting of a
Q[8] molecule with Ce 3 + , is given in Fig. 4.8 as a representative example of the
Ln 3 +

light − Q[8] − [CdCl 4 ] 2 − group. The crystal structure of the Ce 3 + /Q[8] complex
shows that the Q[8] molecule coordinates to four Ce 3 + cation ions. An unusual
interaction between the [CdCl 4 ] 2 − anions and methine or methylene on the outer
surface of the Q[8] molecule can be also observed. Each Ce 3 + /Q[8] complex is