UV and X-ray dual photochromic properties of three CPs based on a new viologen ligand.

A new viologen ligand 1-(1-cyclohexylmethane)-4,4′-bipyridinium bromide (CMbpyBr) in the presence of benzenecarboxylates and metal ions affords three coordination polymers [Zn(CMbpy)(HBTC)Br] n (1), [Cd(CMbpy)(m -BTC)(H 2 O)] n (2) and {[Cd(CMbpy)(m -BDC)(H 2 O) 2 [Cd(m -BDC)(m -HBDC)(H 2 O)]} n (3) (H 3 BTC = 1,3,5-benzenetricarboxylic acid, m -H 3 BTC = 1,2,4-benzenetricarboxylic acid, m -H 2 BDC = 1,3-benzenedicarboxylic acid). Compounds 1 and 3 both have 1D structures, while compound 2 is 3D structure. More importantly, three compounds exhibit excellent photochromic behaviors in response to UV and X-ray dual light due to the formation of viologen radicals. However, the decolorization of the photochromic products for the three compounds is very different. The reason for their different photochromic behaviors has been explored. Image 1 • A new viologen ligand has been used to construct CPs. • Their crystal structures and photochromic properties have been studied. • Three CPs exhibit excellent photochromic behaviors in response to UV and X-ray dual light. [ABSTRACT FROM AUTHOR]