Synthesis of metal–organic frameworks in water at room temperature: salts as linker sources

Abstract

Salts as linker sources allow the preparation of high-quality carboxylate-based MOFs under unprecedented sustainable conditions: room temperature and water as the sole solvent.

An in situ investigation of the water-induced phase transformation of UTSA-74 to MOF-74(Zn)

“…22,23 However, most syntheses are based on the originally reported solvothermal synthesis, 8 where H4dobc and Zn(NO3)2·6H2O are dissolved in N,N-dimethylformamide (DMF) together with a small amount of water, presumably for solubility reasons, and allowed to react at 105 °C.…”

Synthesis, Structure, and Selected Properties of Aluminum-, Gallium-, and Indium-Based Metal-Organic Frameworks

“…Electrochemistry, mechanochemistry, spray drying [57], and ultrasonic methods [58] have also been employed. For the G13-MOFs mainly solvothermal syntheses in autoclaves under conventional heating have been reported but recently, albeit only for the formation of Al-MOFs, room temperature syntheses in water [59,60], and continuous synthesis were described (see Section 5.6.1) [61][62][63]. The solvothermal route has two significant advantages compared to other synthesis methods: (i) It is relatively simple and cost-effective to employ on the lab scale, (ii) it allows for the usage of poorly soluble starting materials, and (iii) variation of chemical and process parameters often leads to new crystalline compounds.…”

“…Hence synthesis methods compatible with industrial needs, that is, low reaction temperatures, low-cost and non-corrosive starting materials, and appropriate metal sources, have been developed [2,63]. Importantly, the use of alkaline metal salts of the linker molecules have been shown to allow the room temperature synthesis of Al-MIL-53 [60] and aluminum fumarate [59].…”

“…Due to the virtually instantaneous precipitation of Al-fumarate, space-time yields up to 15 000 kg m −3 d can be achieved. Al-MIL-53 can be as well synthesized under mild reaction conditions using sodium terephthalates instead of terephthalic acids [60]. Under ambient conditions the three analogues Al-MIL-53-X (with X = -H, -NH 2 , or -NO 2 ) could be isolated.…”

One‐Step Synthesis of MIL‐53(Al)/Boehmite Composites

“…They found, that the synthesis of MIL-53(Al) in DMF at 220°C results in a material with a gradual, slight breathing behavior, while a sample synthesized in DMF at only 120°C does not show a contraction of the structure at all and is stabilized in the ht-form. Another innovative route for the preparation of MIL-53(Al) was recently reported by Sán-chez-Sánchez et al [23]. In this approach the sodium salt of terephthalic acid Na 2 (bdc) is applied as the linker source, leading to a drastically enhanced availability of fully deprotonated terephthalate anions in the synthesis solution and, thereby, a reduction of the synthesis temperature.…”