High Temperature Postsynthetic Rearrangement of Dimethylthiocarbamate-Functionalized Metal–Organic Frameworks

Abstract

. (2016). High temperature postsynthetic rearrangement of dimethylthiocarbamate-functionalized metal-organic frameworks. Crystal Growth and Design, 16 (12),[7067][7068][7069][7070][7071][7072][7073] High temperature postsynthetic rearrangement of dimethylthiocarbamatefunctionalized metal-organic frameworks AbstractA thermally promoted postsynthetic rearrangement has been performed on a zinc IRMOF-9-type framework bearing dimethylthiocarbamate tag groups. The rearrangement was accomplished via conventional heating at 285 °C. Crucially, despite the high temperature, the MOF maintains its high accessible surface area and pore space following thermal treatment. The structures and physical properties of the frameworks were characterized by a combination of single-crystal X-ray diffraction, powder X-ray diffraction, differential thermal-thermogravimetric analysis, and gas sorption analysis. The rearrangement results in a slightly higher level of CO 2 adsorption for the modified MOF but with equivalent heat of adsorption. This work offers new perspectives on postsynthetic rearrangements in MOFs and demonstrates that rearrangements that occur at relatively high temperatures are still compatible with the need to retain the structural integrity and porosity of the framework. A thermally-promoted post-synthetic rearrangement has been performed on a zinc IRMOF-9 type framework bearing dimethylthiocarbamate tag groups. The rearrangement was accomplished via conventional heating at 285 °C. Crucially, despite the high temperature, the MOF maintains its high accessible surface area and pore space following thermal treatment. The structures and physical properties of the frameworks were characterized by a combination of single X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), differential thermalthermogravimetric analysis (DT-TGA), and gas sorption analysis. The rearrangement results in a slightly higher level of CO 2 adsorption for the modified MOF but with equivalent heat of 2 adsorption. This work offers new perspectives on post-synthetic rearrangements in MOFs, and demonstrates that rearrangements that occur at relatively high temperatures are still compatible with the need to retain the structural integrity and porosity of the framework.

The photothermal effect in MOFs: covalent post-synthetic modification of MOFs mediated by UV-Vis light under solvent-free conditions

“…28 Similarly, Richardson et al demonstrated that a Newman-Kwart rearrangement on a dimethylthiocarbamate-functionalized IRMOF-9 occurs by direct heating it at 285 °C. 29 In the study reported here, we extended our previous work on localised photothermal activation of MOFs to perform CPSMs of MOFs under solvent-free conditions. We show that MOFs, once mixed with another reagent and irradiated by a UV-Vis lamp, can simultaneously act as both heater and host for CPSMs.…”

High temperature expulsion of thermolabile groups for pore-space expansion in metal–organic frameworks

“…We have found this to be a common space group for a functionalised IRMOF-9-type compounds. 1,4,[20][21][22] A full description of the asymmetric unit of this structure can be found in the ESI. At their closet point, the frameworks are only 3.5 Å apart but reticulate into a structure with pore sizes of ~5 and ~10 Å (Fig.…”

“…In our experience, gas adsorption isotherms are a more sensitive measure of framework integrity after postsynthetic modifications than PXRD. [1][2][3][4] With this in mind, we recorded N 2 isotherms at 77 K for WUF-18, WUF-19 and WUF-19PSM to ascertain the effects of the modification on surface areas and pore volumes. Fig.…”

“…We are involved in a programme of thermally-promoted post-synthetic modification of MOFs. [1][2][3][4] Provided that the requisite chemical functionality can be incorporated in the framework, thermally-promoted modifications are straightforward to implement as they simply require heating. Most modifications are eliminations and include thermolysis of tert-butoxycarbamates, [5][6][7] hemiaminals, 8 carboxylic acids, 9 and azides.…”

Understanding the Solid-State Assembly of Pharmaceutically-Relevant N,N-Dimethyl-O-Thiocarbamates in the Absence of Labile Hydrogen Bonds

“…This might explain the propensity of O-thiocarbamates to undergo isomerization, where the S and O atom exchange positions to form S-thiocarbamates under catalytic conditions or at elevated temperatures. [33][34] Our initial attempts to grow diffraction quality crystals of 1 were not successful, yielding only oils or thin opaque films. Fortunately, SCXRD data were obtained for compounds 2-15, and preliminary analyses of their crystal structures revealed four distinct types of packing interactions, namely, (i) thiocarbamate-thiocarbamate stacking in an anti-fashion, (ii) thiocarbamate-aryl stacking, (iii) CH-π interaction, and (iv) π-π stacking (Figure 3b).…”