Assembly of a dinuclear silver complex containing an Ag2S2 motif from a phosphorus-supported trishydrazone ligand. PS→AgI coordination

Abstract

The reaction of the phosphorus trihydrazide, (S)P[N(Me)-NH₂]₃ (1) with quinoline-2-carboxaldehyde (C₉H₆N-2-CHO) in a 1 : 3 ratio afforded a trishydrazone, (S)P[N(Me)-NCH-2-C₉H₆N]₃ (2). Crystals of 2 were grown in three different solvent media affording an unsolvated (2, monoclinic, P2₁/n) and two solvated (2·3H₂O, trigonal, R3 and 2·2CH₃OH, triclinic, P) crystal forms. Each of these, while possessing an essentially similar molecular structure, adopt different crystal packing giving rise to supramolecular structures mediated by a variety of weak interactions: O–H–N, O–H–O, C–H–N, C–H–O, C–H–S, C–H–π, π–π, N–π and S–π. The reaction of 2 with Ag(ClO₄)₂·6H₂O in methanol afforded a dinuclear cationic cage [Ag{(S)P[N(Me)-NCH-2-C₉H₆N]₃}·ClO₄]₂ (3). The molecular structure of 3 reveals a dimeric structure consisting of two Ag^I ions that are held together by two ligands. Only two arms of the tris hydrazone ligand are involved in coordination while an unprecedented PS→Ag^I coordination is seen. This results in the formation of an Ag₂S₂ dimer that is encapsulated by two trishydrazone ligands. Both compounds 2 and 3 are photoluminescent.