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 a trinuclear silver(I) cluster by a hexadentate podand

Abstract

The title ligand (L^–) forms a 1:1 complex [TIL] in which the TI^I ion lies within the hexadentate cavity, coordinated strongly by the pyrazolyl N atoms but only very weakly by the pyridyl N atoms; in contrast the 3:2 complex [Ag₃L₂][ClO₄] contains a triangular {Ag₃}³⁺ cluster core within the cavity of each ligand which accommodates the larger guest by increasing the apical N–B–N angles.