Generating Reactive MILs: Isocyanate‐ and Isothiocyanate‐Bearing MILs through Postsynthetic Modification

Volkringer, Christophe; Cohen, Seth M.

doi:10.1002/anie.201001527

Cited by 118 publications

(94 citation statements)

References 42 publications

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“…Before measurements all samples were digested in HF/DMSO-d6. 22 Filled circles refer to amino signals, empty circles to azide species and filled squares to isocyanate groups. 1 H-NMR was used to follow the modification of the ligand 70 substitution due to the strong shift of its aromatic protons and to quantify the degree of conversion of azide into isocyanate groups.…”

Section: Scheme 1 Possible Synthetic Routes To Mof With Pendent Isocmentioning

confidence: 99%

“…On the contrary, strongly electrophilic groups such as isocyanates have been shown to be highly versatile in this respect, allowing the introduction of 30 various carbamate and urea functional groups. 22 The direct synthesis of MOFs possessing such functional groups is difficult, however, so in general these groups are introduced by postsynthetic means. Interestingly, it is possible to transform amino into isocyanate groups in MOFs, but the present method requires 35 the use of diphosgene (route 1 in Scheme 1).…”

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confidence: 99%

“…In fact, the treatment of MIL-53(Al)-NH 2 (MIL: Materials from Institut Lavoisier, Al(OH)(2-amino-1,4-benzenedicarboxylate)) leads to the corresponding MIL-53(Al)-NCO. 22,23 This method cannot, however, be applied to most MOFs, because the diphosgene 40 treatment involves HCl formation, which in turn leads to the solubilisation of the solid.…”

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confidence: 99%

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Soft synthesis of isocyanate-functionalised metal–organic frameworks

et al. 2012

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Section: Scheme 1 Possible Synthetic Routes To Mof With Pendent Isocmentioning

confidence: 99%

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Soft synthesis of isocyanate-functionalised metal–organic frameworks

et al. 2012

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“…As described in our earlier studies, modification was confirmed by nuclear magnetic resonance (NMR) spectroscopy. 20,24 …”

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Isoreticular synthesis and modification of frameworks with the UiO-66 topology

2010

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“…Despite significant advances, the majority of PSM reactions have been confined to MOFs bearing a limited variety of functional group ‘handles’ including amines, aldehydes, alkynes, and a few others 17,18. For example, amino-containing MOFs have been converted to amides,4 iso(thio)cyanates,6 ureas,19 imines,10,11 and azides 13. Novel PSM reactions, which originate from alternative functional group handles, is of great value for advancing the utility of PSM and creating MOF materials that are otherwise inaccessible by conventional synthetic approaches.…”

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Microwave-Assisted Cyanation of an Aryl Bromide Directly on a Metal−Organic Framework

2011

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A microwave-assisted postsynthetic modification (PSM) reaction on a metal-organic framework (MOF) has been realized. Cyanation of the Zr 4+ -based UiO-66-Br was achieved with CuCN and microwave irradiation to produce UiO-66-CN. This protocol represents a significant example of PSM modification on an aryl halide MOF producing a cyano-functionalized MOF.Metal-organic frameworks (MOFs) are porous materials that are constructed from inorganic metal ion clusters and tunable organic linkers. 1 An immense range of MOF materials have been developed to date, mostly under solvothermal reaction conditions.2 In the last decade, MOFs have emerged as an exciting area in inorganic and materials chemistry for use in gas adsorption, separation, catalysis, and drug delivery.3Recently, we4 -7 and others8 -15 have described postsynthetic modification (PSM) as method for manipulating the organic linkers in MOFs. PSM is versatile with regard to the scope of MOF substrates to which it can be applied, and new physical and chemical properties can be realized in MOFs via this approach. 7, 16 Despite significant advances, the majority of PSM reactions have been confined to MOFs bearing a limited variety of functional group 'handles' including amines, aldehydes, alkynes, and a few others.17 , 18 For example, amino-containing MOFs have been converted to amides, 4 iso(thio)cyanates, 6 ureas,19 imines,10 , 11 and azides. 13 Novel PSM reactions, which originate from alternative functional group handles, is of great value for advancing the utility of PSM and creating MOF materials that are otherwise inaccessible by conventional synthetic approaches. Our first attempts at PSM on UiO-66-Br utilized CuCN (1.3 equiv) in a N,Ndimethylformamide (DMF) suspension of UiO-66-Br for 24 h at 140 °C (Scheme 1). 27 After removal of excess copper (Table S1) by washing with DMF, an aqueous KCN solution, and methanol, the bromo groups of UiO-66-Br were found to be ca. 43% converted to nitrile groups. The percent conversion from bromo to nitrile was determined by 1 H NMR upon digestion of the MOF in HF in CD 3 OD, 23 a method now commonly used for characterization of PSM on MOFs. In the 1 H NMR spectra, the 2-cyano-1,4-benzenedicarboxylate (CN-BDC) resonances generated from the UiO-66-CN product (Figure 1, Figure S1) are shifted downfield relative to the Br-BDC starting material.Encouraged by these preliminary results, we sought to improve the cyanation PSM reaction conditions. The high chemical and thermal stability of UiO-66-Br led us to attempt microwave-assisted cyanation. 28 UiO-66-Br was suspended in N-methyl-2-pyrrolidone (NMP) and subjected to microwave irradiation (170 °C, 10 min) producing UiO-66-CN in ca. 90% yield (as determined by 1 H NMR analysis, Figure 1, Figure S2). Electrospray ionization mass spectrometry (ESI-MS) and infrared spectroscopy (ATR-FTIR) also confirmed conversion to the modified CN-BDC ligand ( Figures S3, S4). To the best of our knowledge this is the first time microwave irradiation has been utilized in the PSM of a MOF. ...

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Generating Reactive MILs: Isocyanate‐ and Isothiocyanate‐Bearing MILs through Postsynthetic Modification

Abstract: MILs hold up: Robust aluminum‐based metal–organic frameworks (MIL‐53(Al)‐NH2) can undergo postsynthetic modification with phosgene reagents to produce highly reactive, porous materials bearing isocyanate or isothiocyanate groups (see scheme).

Cited by 118 publications

References 42 publications

Soft synthesis of isocyanate-functionalised metal–organic frameworks

Soft synthesis of isocyanate-functionalised metal–organic frameworks

Isoreticular synthesis and modification of frameworks with the UiO-66 topology

Microwave-Assisted Cyanation of an Aryl Bromide Directly on a Metal−Organic Framework

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