Tunable photochromic properties of hybrid solids controlled by the conjugated length of non-photochromic units

Abstract

Coordinative bonding of the inorganic zincophosphite layer and organic linear bipyridine unit generates two hybrid photochromic frames [Zn(HPO₃)(L)_0.5] (L = 4,4′-bipy for 1, 1,4-dpb for 2). Distinct from the familiar hybrid photochromic materials based on photochromically active moieties, the photochromism in the resultant crystalline hybrid materials is driven by the metal-assisted charge transfer between the phosphite and its corresponding non-photochromic bipyridine units. Interestingly, the photochromic performance of the final products could be modulated via enlarging the conjugated length of the non-photochromic bipyridine units, which provides new insight into the design of superior photochromic materials via tailoring the organic moieties of the parent compound.