The practical applicability of thiolated metal–organic frameworks (MOFs) remains challenging due to their low crystallinity and transient stability. Herein, we present a one-pot solvothermal synthesis process using varying ratios of 2,5-dimercaptoterephthalic acid (DMBD) and 1,4-benzene dicarboxylic acid (100/0, 75/25, 50/50, 25/75, and 0/100) to prepare stable mixed-linker UiO-66-(SH)2 MOFs (ML-U66SX). For each variant, the effects of different linker ratios on the crystallinity, defectiveness, porosity, and particle size have been discussed in detail. In addition, the impact of modulator concentration on these features has also been described. The stability of ML-U66SX MOFs was investigated under reductive and oxidative chemical conditions. The mixed-linker MOFs were used as sacrificial catalyst supports to highlight the interplay of template stability on the rate of the gold-catalyzed 4-nitrophenol hydrogenation reaction. The release of catalytically active gold nanoclusters originating from the framework collapse decreased with the controlled DMBD proportion, resulting in a 59% drop in the normalized rate constants (9.11–3.73 s–1 mg–1). In addition, post-synthetic oxidation (PSO) was used to further probe the stability of the mixed-linker thiol MOFs under harsh oxidative conditions. Following oxidation, the UiO-66-(SH)2 MOF underwent immediate structural breakdown, unlike other mixed-linker variants. Along with crystallinity, the microporous surface area of the post-synthetically oxidized UiO-66-(SH)2 MOF could be increased from 0 to 739 m2 g–1. Thus, the present study delineates a mixed-linker strategy to stabilize the UiO-66-(SH)2 MOF under harsh chemical conditions through meticulous thiol decoration.

Synthesis, storage, and characterization of thiol functionalized metal-organic frameworks (MOFs) is highly challenging. However, they continue to be of great interest due to their broad spectrum of applications. In this work, for the first time, a solid solution approach has been adopted to dilute the thiol content in UiO-66-(SH)2 [Universitetet i Oslo] MOF by terephthalic acid linker without influencing its topology. The solid dilution had an overall impact on the crystallinity, defects, porosity and particle size of the UiO-66-(SH)2 framework. This study has the potential to significantly influence the syntheses of nanoscale thiol functionalized MOF materials and their applications in photocatalysis, water purification and drug delivery. This work also incorporates the performance study of the mixed-linker thiol MOFs under reductive and oxidative conditions. The rate of para-nitrophenolate hydrogenation under reductive conditions were mainly governed by the stability of the mixed-linker MOFs as catalyst supports. Whereas, post synthetic oxidation (PSO) was used to produce sulfonic acid tagged mixed-linker UiO-66 frameworks to probe the behavioral pattern in oxidative conditions of the parent mixed-linker thiol MOFs. The mixed-linker strategy was critical in preventing the frameworks from losing their crystallinity and porosity, upon oxidation. Thus, this work also paves the way for a general strategy to impart stability to thiol tagged UiO-66 framework having wide ranging applications.