Novel One- and Two-Dimensional Ag(I) Networks Generated from Double Schiff Base Ligands with Disubstituted Quinoxaline Diazenes as the Terminal Binding Sites

Abstract

The new double Schiff base ligand L7 (2,5-bis(2-benzodiazine)-3,4-diaza-2,4-hexadiene) with disubstituted quinoxaline diazenes was synthesized. Four new polymeric Ag(I) complexes based on L7, namely {Ag3(L7)3(BF4)3(CH2Cl2)3(H2O)}n (1), {Ag2.5(L7)1.5(ClO4)2.5(H2O)2}n (2), {Ag4(L7)3(PF6)4}n (3), and {Ag4(L7)3(SbF6)4}n (4), have been synthesized successfully. They were fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. In compound 1, two Ag(I) atoms are held together by two L7 ligands through the inside middle chelating N donors to generate a binuclear “X-shaped” helical secondary building block. In compounds 2−4, three Ag(I) atoms are held together by three L7 ligands through the inside middle chelating N donors to afford a trinuclear crownlike secondary building block. These spontaneous self-organized supramolecular secondary building blocks were further linked together into the higher extended hierarchy through outside N−Ag(I) coordination interactions. Compound 1 features a two-dimensional net containing a molecular cage, and compounds 2−4 feature two- (2 and 3) and one-dimensional (4) molecular crown-containing polymeric complexes in the solid state, respectively.