CRYSTAL-STRUCTURES OF SILVER(I) AND THALLIUM(I) COMPLEXES OF TRIS[3-(2-PYRIDYL)-PYRAZOL-1-YL]BORATE - ENCAPSULATION OF EITHER A SINGLE THALLIUM(I) ION OR TRINUCLEAR SILVER(I) CLUSTER BY A HEXADENTATE PODAND

The title ligand (L(-)) forms a 1:1 complex [TIL] in which the Tl-I io n lies within the hexadentate cavity, coordinated strongly by the pyra zolyl N atoms but only very weakly by the pyridyl N atoms; in contrast the 3:2 complex [Ag(3)L(2)][ClO4] contains a triangular {Ag-3}(3)+ cl uster core within the cavity of each ligand which accommodates the lar ger guest by increasing the apical N-B-N angles.