Two cadmium compounds with adenine and carboxylate ligands: syntheses, structures and photoluminescence

<p>Two cadmium(II) coordination compounds, [Cd<sub>3</sub>(CH<sub>3</sub>CO<sub>2</sub>)<sub>4</sub>(ad)<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub>]<sub>n</sub> (<b>1</b>) and [Cd<sub>3</sub>(5-SIP)<sub>2</sub>(H-ad)<sub>2</sub>(H<sub>2</sub>O)<sub>6</sub>]<sub>n</sub> (<b>2</b>) (H-ad = adenine and 5-SIP = 5-sulfoisophthalate), were synthesized and characterized. Compound <b>1</b> features a two-dimensional (2-D) layered structure based on linear trinuclear [Cd<sub>3</sub>(CH<sub>3</sub>CO<sub>2</sub>)<sub>4</sub>] units bridged by monoanionic adenine ligands. In <b>2</b>, the 5-SIP<sup>3−</sup> ligands link Cd(II) ions to form a one-dimensional (1-D) ladder, which is further linked by neutral adenine ligands to give a 2-D layered structure. In both structures, the carboxylate ligands link Cd(II) ions to form low-dimensional structures, which are further connected by adenine ligands to give high-dimensional structures. Compounds <b>1</b> and <b>2</b> exhibit emissions centered at 382 and 416 nm, respectively, which can be attributed to the ligand centered <i>π</i>–<i>π</i>* transition.</p>