Variable-Temperature Photocyclization Kinetics in a Metal-Organic Framework (MOF): A Comparison of the Johnson-Mehl-Avrami-Kolmogorov and Finke-Watzky Models

Photocyclizationreactions are a useful tool for modulatingtheproperties of metal-organic frameworks (MOFs). Fully characterizingthese structural transitions is an important step in the developmentand deployment of MOF-based photoactive devices and smart materials.At present the quantitative measurement and modeling of photocyclizationreactions in MOF materials has received relatively limited attention.In this work two different solid-state kinetic models are used tocharactrerize a thermally reversible [2 + 2] photocyclization in [Cd-2-(bpdc)(2)-(Py-2-TTF)(2)] (bpdc = biphenyl-4,4 & PRIME;-dicarboxylic acid Py2TTF = 2,6-bis(4 & PRIME;-pyridyl)-tetrathiafulvalene). Significantdifferences in the goodness-of-fit dependent on the reaction ratewere observed between the two models, with the Finke-Watzkymodel providing a more accurate fit for the data. This work monitors the temperature-dependent [2 + 2] photocyclizationobserved in the cofacial TTF ligands of [Cd(bpdc)(2)(Py2TTF)(2)] via Raman spectroscopy and describes thesubsequent treatment of the kinetic data with two different solid-statekinetic models; Finke-Watzky (FW) and Johnson-Mehl-Avrami-Kolmogorov(JMAK).

Automated summary

This work investigates the application of two different solid-state kinetic models in the [2 + 2] photocyclization reaction of MOF materials, and finds that the Finke-Watzky model provides a more accurate fit for the data.