Substituent Effects on the Supramolecular Aggregation of Ag^I-Pyrazolato Trimers

Abstract

The interplay of argentophilic and dipolar (π-acid···base) interactions, on one hand, and the presence or absence of interstitial solvent molecules, on the other, determines the supramolecular organization of trinuclear silver-pyrazolato complexes in the solid state. The crystal structures of one gold and six silver metallacyclic complexes of the type [M I (μ-pz*)] 3, where pz* are the substituted pyrazolato anions 3,5-Ph 2 -pz, 3-Me-5-Ph-pz, 4-Br-3,5-Ph 2 -pz, 4-Br-3- t Bu-pz and 3-( o -Cl-C 6 H 4 )-pz and M = Ag and Au, are discussed in the context of their supramolecular organization. Two silver complexes, for which the π-acid character of their Ag 3 -faces is maximized by their peripheral electron-withdrawing substituents, show crystal packing dominated by short Ag 3 ···Br contacts, the first structural manifestation of supramolecular structure via dipolar interactions involving the tunable π-acidity of the Ag 3 -face.