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.