Anion Dependent Structures of Luminescent Silver(I) Complexes

The reaction of AgX, where X = trifluoroacetate (CF3CO2-, tfa), nitrate (NO3-), trifluoromethanesulfonate (triflate,
CF3SO3-, OTf), hexafluorophosphate (PF6-), or perchlorate (ClO4-), with 2,2‘,3‘ ‘-tripyridylamine (tpa) yields five
novel silver(I) complexes, which have been structurally characterized. The five complexes have the same 1:1
stoichiometry of Ag/tpa but exhibit different modes of coordination, depending upon the counterion present in the
compound. Compound 1, [Ag(tpa)(tfa)]n, forms a 1D coordination polymer of [Ag(tpa)(tfa)]2 dimer units linked through
bridging tfa counterions. Compound 2, [Ag(tpa)(CH3CN)(NO3)]n, forms a zigzag chain 1D coordination polymer
exclusively through Ag−N bonds. In compounds 1 and 2, each tpa ligand is bound to two Ag(I) ions via a 2-py and
a 3-py group. Compound 3, [Ag(tpa)(OTf)]n, forms a ribbonlike 1D coordination polymer, in which each tpa ligand
binds to three different silver centers via all three pyridyl groups, and the counterion remains coordinated to the
Ag(I) center. Compounds 4, [Ag(tpa)(CH3CN)]n(PF6)n, and 5, [Ag(tpa)(CH3CN)]n (ClO4)n, display ribbonlike structures
resembling that of 3, except that the counterions are not coordinated. All complexes are luminescent in acetonitrile
solution, with emission maxima in the near-UV region (λmax = 366, 368, 367, 367, and 368 nm for 1−5, respectively).
At 77 K, the emission maxima are red-shifted to λmax = 452, 453, 450, 450, and 454 nm for 1−5, respectively.