Thermally induced 1D to 2D polymer conversion accompanied by major packing changes in singlecrystal-to-single-crystal transformation

An unprecedented thermal response is observed in [(4,4'-bpe center dot 2H(+))(HSO4-)(2)] (1), a hydrogen-bonded 1D coordination polymer. While 1 was photostable to irradiation at 365 nm, upon heating at 70 degrees C for 1 h, it transformed into 1ph, a 2D polymer, through single-crystal-to-single-crystal transformation (SCSCT). In this conversion, a series of bonds are broken and re-formed simultaneously, leading to major changes in the packing pattern which is quite rare in SCSCT.