A unified topology approach to dot-, rod-, and sheet-MOFs

Abstract

We offer insights into how network topology influences stability of metal-organic frameworks and suggest the application of rare sheet-MOFs, where metal ions and linkers form infinite 2D units (SBUs) as a strategy for achieving higher stability. We also demonstrate a unified topology approach to MOFs exemplified by the dot-, rod-, and sheet-MOFs reported. These MOFs are based on vicinal dicarboxylates, which we propose as a way to prepare rod-MOFs. Cyclic voltammetry suggests Ce(IV)-MOFs as being more stable than expected with potential electrochemical applications.

Metal–organic frameworks based on infinite secondary building units: recent progress and future outlooks

“…Besides, ISBU MOFs based on transition metals( iii ) have also been prevailingly studied. 21,31,97–100 The recently emerged CAU-50 (ref. 99) [Sc 2 (FcDC) 3 ] was a 1D Sc-MOF constructed by reacting Sc(NO 3 ) 3 ·5H 2 O with H 2 FcDC in a mixture of water and DMF at 95 °C.…”

“…12f). Öhrström et al 21 reported a type of 1D Gd-MOF from the reaction of Gd(NO 3 ) 3 ·6H 2 O with benzene-1,2,4,5-tetracarboxylate (H 4 BTEC), 4,4′-azopyridine in a mixture of DMF and acetic acid. The central Gd 3+ among the obtained CTH-16 [Gd 2 (BTEC) 2 ] was coordinated by nine carboxylate oxygens from six different BTEC ligands (Fig.…”

“…Moreover, the same research group reported the 2D Ce( iii )-MOF by reacting Ce(NO 3 ) 3 ·6H 2 O with H 4 BTEC in a mixture of DMF and acetic acid. 21 The obtained product (denoted as CTH-15 thereafter) had the molecular formula of [Ce 3 (BTEC)(HBTEC)(OAc)(HCO 2 )] and crystallized in the monoclinic crystal system and the P 2 1 / c space group. As shown in Fig.…”

“…7–11 In most cases, the metal ions or metallic secondary building units (SBUs) are considered as discrete zero-dimensional (0D) nodes that are further linked by organic ligands for the construction of frameworks. 12–15 Distinctly, infinite SBUs (ISBUs) like one-dimensional (1D) chains, 16–18 two-dimensional (2D) sheets, 19–21 and even three-dimensional (3D) nets 22–24 have also emerged in MOFs and been rapidly developed recently. Consequently, MOFs can also be categorized into OD, 1D, 2D, and 3D subclasses according to the ISBU types (Scheme 1).…”

“…, excellent stability, high carrier mobility and dense unit package). 21,25–27 To a certain degree, ISBU MOFs can be even considered as special assemblies of metal-oxide/hydroxide nanostructures ( e.g. nanowires, nanosheets and nano-frames) and organic linkers.…”