Synthesis of a tetratopic bisphosphine ligand derived from pyrimidine and its incorporation into gold and silver coordination polymers

Abstract

Herein we present the synthesis of a tetratopic bisphosphine ligand derived from 4,6-disubstituted pyrimidine scaffold. This new ligand (2) was doubly alkylated using iodomethane to give bisphosphonium dication (3) as an iodide salt, and was also coordinated to both gold(I) chloride to give the metal complex (4) and to silver(I) triflate to give a coordination polymer (5), respectively. All compounds have been fully characterized using multinuclear NMR spectroscopy as well as single crystal X-ray diffraction. Gold complex 4 was also found to exhibit weak emission at λmax = 530 nm due to Au(I)–Au(I) aurophilic interactions. Additionally we demonstrated that bisphosphine ligand 2 can be used as a tetratopic ligand, as evidenced by the formation of the coordination polymer 5 in which both phosphine → silver and nitrogen → silver interactions were observed.