Isoreticular Metal-organic Framework-3 Research Articles

Designing Near‐Infrared and Visible Light Emitters by Postsynthetic Modification of Ln+3–IRMOF‐3

AbstractThe postsynthetic modification of metal–organic frameworks is a promising new route for engineering optical centres and tuning the light emission properties of materials. Here, the postsynthetic modification of isoreticular metal–organic framework‐3 (IRMOF‐3) with ethyl oxalyl monochloride and ethyl acetoacetate followed by the chelation of trivalent lanthanide ions afforded efficient near‐infrared (Nd3+) and visible (Eu3+ and Tb3+) light emitters. IRMOF‐3 was used as an example owing to its highly porous crystalline structure and the presence of non‐coordinating amino groups on the benzenedicarboxylate (bdc) linker, which are amenable to modification. The conversion of the amino groups was 100 and 65 % for ethyl oxalyl monochloride and ethyl acetoacetate, respectively. The materials were characterised by elemental analysis, powder X‐ray diffraction, optical and scanning electron microscopy, Fourier transform infrared spectroscopy, and solution (1H) and (13C) solid‐state nuclear magnetic resonance spectroscopy. The solid‐state luminescence properties of Ln‐modified IRMOF‐3 were investigated at room temperature. The presence of the bdc aromatic ring, β‐diketonates and oxamate enhanced the Ln3+ sensitization through ligand‐to‐metal energy transfer. The magnetic behaviour of all compounds was further analysed. The spin–orbit coupling and zero‐field splitting parameters were evaluated by fitting the experimental magnetic susceptibility to the analytical expressions for the free Ln3+ ions.

A MOF-supported chromium catalyst for ethylene polymerization through post-synthetic modification

Isoreticular metal-organic framework-3 (IRMOF-3) has been post-synthetically modified to generate a Cr(III)-based heterogeneous catalyst (IRMOF-3-SI-Cr) for ethylene polymerization, which has been characterized by a variety of physical methods. The XRD analysis indicated that the structure integrity of the final solid was preserved after the functionalization with the imine and the subsequent coordination to chromium. The BET surface area of the final solid was slightly reduced as determined by N2 adsorption–desorption experiments. The material exhibited a unique behavior for ethylene polymerization upon activation with various alkylaluminium co-catalysts, and the polyethylenes formed featured high molecular weights and broad molecular weight distributions.

Fine tuning of gold electronic structure by IRMOF post-synthetic modification

In this communication, we present a strategy to fine-tune the electronic structure of gold atoms by means of post-synthetic modification of IRMOF-3 (iso-reticular metal organic framework-3) with salicylaldehyde derivatives. Changes in the electronic structure of gold were predicted by theoretical calculations and determined by resonant inelastic X-ray scattering (RIXS) at the gold L3 edge. Modification of the coordinating group affected the relative HOMO and LUMO energy levels, resulting in a change of the HOMO–LUMO gap. The ability to fine tune electronic structure may lead to tailoring of the catalytic performance and material electronics states.

Functionalized IRMOF-3 as efficient heterogeneous catalyst for the synthesis of cyclic carbonates

Functionalized isoreticular metal–organic framework-3 (IRMOF-3) was developed as a novel heterogeneous catalyst for the solventless synthesis of cyclic carbonates without any co-catalyst. The results showed that functionalized IRMOF-3 performed excellent activity, selectivity and reusability. The effects of reaction temperature, pressure, and time on the yield of propylene carbonate were tested. And the reaction mechanism was also discussed.

Systematic Functionalization of a Metal−Organic Framework via a Postsynthetic Modification Approach

The pendant amino groups in isoreticular metal-organic framework-3 (IRMOF-3) were subjected to postsynthetic modification with 10 linear alkyl anhydrides (O(CO(CH2)nCH3)2 (where n = 1 to 18) and the extent of conversion, thermal and structural stability, and Brunauer-Emmett-Teller (BET) surface areas of the resulting materials were probed. (1)H NMR of digested samples showed that longer alkyl chain anhydrides resulted in lower conversions of IRMOF-3 to the corresponding amide framework (designated as IRMOF-3-AM2 to IRMOF-3-AM19). Percent conversions ranged from essentially quantitative (approximately 99%, -AM2) to approximately 7% (-AM19) with IRMOF-3 samples. Modified samples were thermally stable up to approximately 430 degrees C and remained crystalline based on powder X-ray diffraction (PXRD) measurements. Under specific reaction conditions, significant conversions were obtained with complete retention of crystallinity, as verified by single-crystal X-ray diffraction experiments. Single crystals of modified IRMOF-3 samples all showed that the F-centered cubic framework was preserved. All single crystals used for X-ray diffraction were analyzed by electrospray ionization mass spectrometry (ESI-MS) to confirm that these frameworks contained the modified 1,4-benzenedicarboxylate ligand. Single crystals of each modified IRMOF-3 were further characterized by measuring the dinitrogen gas sorption of each framework to determine the effects of modification on the porosity of the MOF. BET surface areas (m(2)/g) confirmed that all modified IRMOF-3 samples maintained microporosity regardless of the extent of modification. The surface area of modified MOFs was found to correlate to the size and number of substituents added to the framework.

Covalent modification of a metal–organic framework with isocyanates: probing substrate scope and reactivity

Isoreticular metal-organic framework-3 (IRMOF-3) has been postsynthetically modified with isocyanates to generate unprecedented, microporous urea-functionalized frameworks.