Azulene‑1‑carboxylate - A new azulene-based building block for coordination polymers

Abstract For the first time, the easily accessible azulene‑1‑carboxylate anion has been employed as building block for the construction of crystalline coordination polymers. Neutralization of azulene‑1‑carboxylic acid ( 3 ) with NaOH in aqueous solution provided the dark purple sodium salt C 10 H 7 CO 2 Na·H 2 O ( 4 ) in 85% isolated yield. Single-crystal X-ray diffraction of 4 revealed a supramolecular layer structure in the crystalline state. Subsequent treatment of 4 with 1 equiv. of Me 3 SnCl afforded a rare organotin derivative of azulene, namely polymeric [C 10 H 7 CO 2 SnMe 3 ] n ( 5 ) as purple crystals (82% yield).