Tuning the flexibility in MOFs by SBU functionalization

Abstract

A new approach for the fine tuning of flexibility in MOFs, involving functionalization of the secondary building unit, is presented. The "gate pressure" MOF [Zn3(bpydc)2(HCOO)2] was used as a model material and SBU functionalization was performed by using monocarboxylic acids such as acetic, benzoic or cinnamic acids instead of formic acid in the synthesis. The resulting materials are isomorphous to [Zn3(bpydc)2(HCOO)2] in the "as made" form, but show different structural dynamics during the guest removal. The activated materials have entirely different properties in the nitrogen physisorption experiments clearly showing the tunability of the gate pressure, at which the structural transformation occurs, by using monocarboxylic acids with varying backbone structure in the synthesis. Thus, increasing the number of carbon atoms in the backbone leads to the decreasing gate pressure required to initiate the structural transition. Moreover, in situ adsorption/PXRD data suggest differences in the mechanism of the structural transformations: from "gate opening" in the case of formic acid to "breathing" if benzoic acid is used.

Fulleretic Well‐Defined Scaffolds: Donor–Fullerene Alignment Through Metal Coordination and Its Effect on Photophysics

“…[12][13][14][15] Furthermore,n one of these studies explore the concept demonstrated herein, which tackles the development of an ovel crystalline metal-donor-acceptor framework, in which control of the mutual orientation of the donor and fullerenebased acceptor was achieved through chemical bond formation, that is,m etal coordination. Despite the tremendous interest in self-assemblies (in particular,c oordination polymers such as covalent or metal-organic frameworks;COFs or MOFs) [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and fullerene chemistry,t ot he best of our knowledge the prepared metal-organic fullerene-containing framework is the first example of ac rystalline hybridextended structure,inw hich control over mutual orientation of both donor and fullerene-based acceptor is achieved through metal coordination (Scheme 1). Scheme 1.…”

Breathing 3D Frameworks with T-Shaped Connecting Ligand Exhibiting Solvent Induction, Metal Ions Effect and Luminescent Properties

“…Besides that, auxiliary ligands were also introduced to tune the flexibility of the frameworks [24]. It is interesting that there are relatively fewer reports on the flexible PCPs that are constructed with homometallic ions and pure H2bpdc ligand as T-shaped connecting modes, especially in type a [25].…”

“…To construct 3D flexible PCPs, although type a (T-shaped connecting mode) is reported more frequently, type c (linear bridging mode) is the most favorable option because the bpdc 2− ligands in the former type often act essentially as rigid spacers [20][21][22][23]. Besides that, auxiliary ligands were also introduced to tune the flexibility of the frameworks [24]. It is interesting that there are relatively fewer reports on the flexible PCPs that are constructed with homometallic ions and pure H 2 bpdc ligand as T-shaped connecting modes, especially in type a [25].…”

“…The multidentate ligand 2,2 -bipyridine-5,5 -dicarboxylic acid (H 2 bpdc) is a good candidate because it contains two types of coordination groups-carboxylate groups and chelating position N-donors-which can act in linear bridging mode and/or T-shaped connecting mode [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. To date, there are 20 different coordination modes for H 2 bpdc ligand observed in the structures retrieved from the Cambridge Structural Database (CSD version 5.38, February 2017) [38] (Figure 1, Scheme S1).…”

Fulleretic Well‐Defined Scaffolds: Donor–Fullerene Alignment Through Metal Coordination and Its Effect on Photophysics

“…[12][13][14][15] Furthermore,n one of these studies explore the concept demonstrated herein, which tackles the development of an ovel crystalline metal-donor-acceptor framework, in which control of the mutual orientation of the donor and fullerenebased acceptor was achieved through chemical bond formation, that is,m etal coordination. Despite the tremendous interest in self-assemblies (in particular,c oordination polymers such as covalent or metal-organic frameworks;COFs or MOFs) [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and fullerene chemistry,t ot he best of our knowledge the prepared metal-organic fullerene-containing framework is the first example of ac rystalline hybridextended structure,inw hich control over mutual orientation of both donor and fullerene-based acceptor is achieved through metal coordination (Scheme 1). Scheme 1.…”