Dynamic ring-opening polymerization of silver(I) complexes with bis(amidopyridine) ligands.

The factors which influence the formation of chelate, macrocycle or polymer in the reaction of silver(i) salts with bis(pyridine) ligands have been probed by studying structures in the solid state and cold spray ionization mass spectra in solution, with the ligands C(6)H(4)-1,3-CONR(CH(2))(n)-3-C(5)H(4)N, 1 (R = Me, n = 0) or (R = H, n = 1) or 5-t-Bu-C(6)H(3)-1,3-CONR(CH(2))(n)-4-C(5)H(4)N, 2 (R = Me, n = 0) or 4 (R = H, n = 1). In both the solid state and solution, the complex [Ag12)]BF(4) exists as a chelate complex 5. The ligands NN = 2-4 form complexes in the solid state with either macrocyclic structures [Ag(2)(mu-NN)(2)]X(2) [6, NN =2, X = BF(4); 9, NN = 3, X = NO(3)] or polymeric structures [7, NN = 2, X = NO(3); 8, NN = 3, X = CF(3)CO(2); 10, NN = 4, X = CF(3)CO(2)]. The ligands 2 and 3 gave both macrocyclic and polymeric complexes, depending on the anion. In solution, these complexes existed as mixtures of macrocycles and ring-opened oligomers. In the crystalline state, the complexes 6-10 underwent supramolecular association through combinations of hydrogen bonding, secondary bonding of the type Ag...X to anions, or argentophilic bonding of the type Ag...Ag.