Controlled assembly of zero-, one- and two-dimensional metal-organic frameworks involving in situ ligand synthesis under different reaction pH

Five cadmium(II) metal-organic frameworks, namely [Cd(BIPA)(daf)(H2O)3] · 2H2O (1), Cd2(BDC)2(pdon)2(H2O)2 (2), Cd(BIPA)(pdon) (3), Cd(BIPA)(daf) (4) and [Cd2(BIPA)2(pdon)2] · H2O (5) (H2BIPA = 5-bromoisophthalic acid, H2BDC = terephthalic acid, pdon = 1,10-phenanthroline-5,6-dione, daf = 4,5-diaza-fluoren-9-one), have been constructed from cadmium(II) salts with multi-carboxylate ligands and pdon ligands under different reaction pH. The framework structures of these polymeric complexes have been determined by the X-ray single crystal diffraction technique. The differences of the five metal-organic frameworks demonstrate that the reaction pH has an important effect on the structure of these complexes. The thermal analyses of these five complexes have been measured and discussed. Additionally, four complexes show strong fluorescence in the solid state at room temperature.

Graphical abstractA series of novel metal-organic frameworks have been fabricated by cadmium(II) salts with multi-carboxylate ligands and pdon ligands under different reaction pH. The differences of five metal-organic frameworks demonstrate that the reaction pH has an important effect on the structures of these complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide