A one-dimensional linear samarium-containing Dawson-type phosphotungstate with photochromic behavior

A one-dimensional linear chainlike phosphotungstate based on Dawson-type [P 2 W 17 O 61 ] 10- building unit was synthesized, which exhibits reversible photochromic behavior. • A one-dimensional linear chainlike phosphotungstate was synthesized. • Constructed by monolacunary Dawson-type [α 2 -P 2 W 17 O 61 ] 10- unit. • Shows reversible photochromic property. A one-dimensional linear chainlike phosphotungstate based on Dawson-type [P 2 W 17 O 61 ] 10- building unit [H 2 N(CH 3 ) 2 ]{Sm 2 (H 2 O) 15 [Sm(H 2 O) 3 (α 2 -P 2 W 17 O 61 )]}⋅21H 2 O ( 1 ) was prepared under routine aqueous condition, which was further characterized by IR spectroscopy, elemental analysis, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and UV–vis diffuse reflectance spectra. Single-crystal X-ray diffraction result illustrated that compound 1 displays a one-dimensional infinite chainlike architecture constructed by monolacunary Dawson-type [α 2 -P 2 W 17 O 61 ] 10- building unit and Sm 3+ connectors. The reversible photochromic property of 1 was tested under UV radiation, which was able to change from white to visible saturated blue in 2 min and recover the natural state after dark treatment for about 10 h.