Characterization of a Photoswitching Chelator with Light-Modulated Geometric, Electronic, and Metal-Binding Properties

Abstract

Photoswitching molecules are utilized for a variety of applications where the rapid manipulation of the molecules' chemical properties and spatial orientations allows for new spatiotemporal control over molecular-scale interactions and processes. Here, we present a hydrazone-containing transition metal chelator, HAPI ((E)-N'-[1-(2-hydroxyphenyl)ethyliden]isonicotinoylhydrazide), that displays dual-wavelength photoswitching behavior. Several of its metal complexes, however, are inert to photoreaction and thereby add another layer of control over the photoswitch system. The light-induced twist in HAPI structure is accompanied by a dramatic change in electronic properties as well as chelator strength. This work introduces HAPI as the prototype for a class of molecules with properties that may be optimized for a variety of experimental applications that take advantage of phototriggered molecular changes.

Coordination Structure Conversion of Hydrazone–Palladium(II) Complexes in the Solid State and in Solution

“…9 Photoinduced E-to-Z isomerization of arylhydrazones are well mentioned in the paper and the cited references. (E)-N′-[1-(2-Hydroxyphenyl)ethylidene]isonicotinoylhydrazide was photoisomerized to the Z isomer with UV light (λ = ∼400−315 nm) in solution and reverted to the original E isomer by UV-light irradiation (λ = 254 nm) or heating.…”

Synthesis of spiropyran-containing random copolymer by atom transfer radical polymerization and its complexation with metal ions

“…As described in the literature, [50][51][52] an extremely important factor for changing the equilibrium of SP and MC is the metal chelation modulation, and there is a similarity in those reports that the nitrogen atom can generate interactive force with the positively charged metal ions. The mechanism of complexation behavior is schematically shown in Figure 10.…”

A multifunctional, light-activated prochelator inhibits UVA-induced oxidative stress

“…These changes can be attributed to partial E-Z isomerization of the HAPI hydrazone bond, which we previously reported. 48 The intensity and duration of irradiation in the current experiment is clearly not sufficient to fully photoisomerize the HAPI sample, as the metastable Z isomer has very little absorption at 400 nm. 48 Interestingly, the spectrum of PC-HAPI does not continue to lose absorbance at 400 nm upon longer irradiation times, suggesting that the coumarin chromophore may inhibit HAPI photoisomerization by a filter effect.…”