Tuning the Extended Structure and Electronic Properties of Gold(I) Thienyl Pyrazolates

A series of thienyl pyrazole proligands and gold­(I) thienyl pyrazolate cyclic trinuclear complexes (CTCs) have been synthesized. The relationship between the structure and emission properties of bridging thienyl pyrazolates within gold­(I) cyclic trinuclear complexes suggests that the nature of dual emission is sensitive to ligand conjugation length. Density functional theory has been used to support the assignment of metal-sensitized, ligand-localized phosphorescence from monothienyl complexes, while low-lying, ligand-localized LUMOs present in bithienyl systems prohibit metal-sensitized phosphorescence. Soluble n-hexyl derivatives have been synthesized to explore the electrochemical properties of gold­(I) thienyl pyrazolates CTCs, and conductive electropolymerized thin films were realized.