Di- and polynuclear silver(I) derivatives with a new multitopic pyrimidine-base tri-thioether ligand

Four novel silver(I) derivatives containing a new flexible multitopic ligand L, incorporating both the pyrimidine and the thioether linkages, have been synthesized and characterized. The X-ray crystal structure of the ligand L shows that two of the three arms of the free ligand adopt an anti geometry about the CH2-S bonds, while the third one is in a distorted gauche conformation. [(L)Ag(BF4)] and [(L)Ag(PF6)] are insoluble likely polymeric species, with a cationic network and uncoordinated anions. However, soluble derivatives are obtained with AgNO3 and AgCF3SO3, where the counter-ions in the solid state are coordinated to the Ag(I) ion. The X-ray crystal structure of derivative [(L)Ag(NO3)] is composed by dinuclear molecules in which each L bridges two silver ions through the coordination of the nitrogen atoms of two pyrimidine rings. All silver(I) derivatives emits bluish-green light with a maximum emission at 517 nm, when excited at 370 nm source. The quite low emission increases by five times for derivative [(L)Ag(CF3SO3)] on cooling to 50 K.