Paving the Way to the First Functional Fulgide@MOF Hybrid Materials

Abstract

The demand for new materials for data storage devices has increased significantly in recent years. In particular, photoswitchable systems will have an essential impact on the construction of new memory devices. In this respect, thermally stable materials are desired to be implemented as device components. Here, hybrid systems consisting of a porous host and a photochromic molecule form the foundation for such composites. In this work, we present the first hybrid materials consisting of the photoswitchable fulgide Aberchrome 670 and porous metal–organic frameworks (MOFs) of varying polarity exhibiting P-type photochromism upon light irradiation. From a fundamental point of view, this MOF embedment further enabled to trace the IR signatures of both the initial and irradiated state of Aberchrome 670 under ambient conditions, which are in correspondence with the results obtained via quantum-chemical calculations. It is precisely in these points that the interface between basic and applied research demonstrates the importance of the switch@MOF research field.

Fundamental Study of the Optical and Vibrational Properties of Fx-AZB@MOF systems as Functions of Dye Substitution and the Loading Amount

“…The composition of the obtained F8-AZB x @DMOF-1 systems was performed via liquid-state NMR spectroscopy following the procedure previously described for diarylethenes, 11 , 12 spirooxazines, 17 spiropyrans, 16 F4-AZB, 9 and fulgides 18 inside different MOF hosts. For this, the respective compound was digested in DMSO- d 6 and DCl.…”

“…The conclusions drawn from the DFTB MD simulations are further emphasized by the analysis of the experimental vibrational difference spectra, which were compared to their theoretically calculated counterparts. In a previous study on fulgide@MOF, 18 a similar analysis enabled the discrimination of the photoswitching mechanism by comparing the differences in the vibrational spectra obtained for the initial state prior to irradiation with those obtained for two potential reaction products. Figure 9 depicts a comparison of the theoretically determined vibrational difference spectra obtained for the E → Z transition of F8- and F10-AZB in comparison to the experimental results determined as the difference in the initial state and measurements obtained after irradiation at 405 and 535 nm, respectively ( Figure 3 , top and bottom, and Figures S20 and S21 , Supporting Information).…”

“… 62 To approximate the influence of the surrounding material, the SMD method (solvation model density) was employed using a permittivity of 28.735 corresponding to ethanol as successfully applied in a previous study. 18 The calculated vibrational frequencies ν calc have been scaled by the procedure reported by Katari and co-workers, 63 which, instead of a constant scaling factor, employs a linear equation of the form Parameters a and b were set to 1.0726 and −63.0 cm –1 , respectively, as recommended for the B3LYP/6-31G(d,p) level of theory. The respective equilibrium geometries and the unscaled vibrational frequencies ν calc are listed in the Supporting Information, Tables S1–S8 .…”

“…62 To approximate the influence of the surrounding material, the SMD method (solvation model density) was employed using a permittivity of 28.735 corresponding to ethanol as successfully applied in a previous study. 18 The calculated vibrational frequencies ν calc have been scaled by the procedure reported by Katari and co-workers, 63 which, instead of a constant scaling factor, employs a linear equation of the form b a…”

A photoprogrammable electronic nose with switchable selectivity for VOCs using MOF films

“… 23,24,78,79 While the focus of our work has been on azobenzenes, the concept can also be applied to MOF films with other photoresponsive groups such as spiropyrans, 80,81 diarylethenes 82,83 or fulgides. 84 In addition to reversible photoisomerization, irreversible light-induced processes in MOFs can also be used. 85,86 Moreover, by using photoresponsive chiral MOF films, the realization of photoprogrammable enantioselective e-noses should be possible.…”