One‐, Two‐ and Three‐Periodic Metal–Organic Rotaxane Frameworks (MORFs): Linking Cationic Transition‐Metal Nodes with an Anionic Rotaxane Ligand

Abstract

A new singly charged pyridinium axle was prepared and combined with disulfonated dibenzo[24]crown-8 ether to form a [2]pseudorotaxane. The reaction of this new, anionic ligand with Zn(II) ions, under various crystallization conditions, resulted in the formation of three metal-organic rotaxane framework (MORF) solids; a one-periodic ML coordination polymer and two, two-periodic ML(2) square grid frameworks. The layers of square grids can be pillared to create full three-periodic MORF structures, which have completely neutral frameworks and are porous. These three-periodic materials represent the first examples of neutral porous MOFs in which one (or more) of the linkers is a mechanically interlocked molecule (MIM).

An Unprecedented Two‐Fold Nested Super‐Polyrotaxane: Sulfate‐Directed Hierarchical Polythreading Assembly of Uranyl Polyrotaxane Moieties

“…As a typical O‐donor anion, the coordination capacity of the sulfate ion is comparable to other O‐donor ligands, such as the carboxylate group. Loeb et al . reported previously a similar phenomenon of controlling the structure of Zn‐based MORFs by the sulfate ion.…”

“…As atypical O-donor anion,t he coordinationc apacity of the sulfate ion is comparablet oo ther O-donorl igands, such as the carboxylate group. Loeb et al [23] reported previously as imilar phenomenon of controlling the structure of Zn-based MORFs by the sulfatei on. Our group recently afforded another two cases involvingt he uranyl center, [17a, b] which demonstrated its moderate binding affinity to the uranyl ion.…”

Metal–Organic Frameworks Incorporating Copper‐Complexed Rotaxanes

“…In addition, [2]rotaxanes, wherein the dumbbell components function as struts in the frameworks, have also been incorporated4 into MOFs. While this strategy has been applied4a–f to the preparation of a number of 2D and 3D frameworks from [2]pseudorotaxanate subunits, it remains a challenge to locate switchable rotaxanes and catenanes inside extended frameworks. Metal‐containing MIMs—particularly those based on the well‐known5 copper(I)‐templated systems—offer the opportunity to locate switches within MOFs.…”

New Silver(I) Coordination Polymer with Fe4 Single-Molecule Magnets as Long Spacer

“…Following Scheme 1, the cross-coupling reaction between 2-(4-bromophenyl)ethanol and pyridin-4-ylboronic acid was performed on the basis of a procedure reported in the literature [28] by means of Pd(PPh 3 ) 4 as catalyst. The presence of the pyridyl group gave us the opportunity to separate the product 1 from N,N-dimethylformamide (DMF) by precipitating it as hydrochloride salt, avoiding the use of column chromatography and still guaranteeing good yield and optimal purity as detectable with GC-MS and 1 H NMR analyses.…”

“…This compound was obtained with a modification of a published procedure [28], especially in the final purification step. 2-(4-bromophenyl)ethanol (1.00 g, 4.97 mmol), pyridin-4-ylboronic acid (0.552 g, 4.49 mmol), and Na 2 CO 3 (0.526 g, 4.97 mmol) were introduced in a Schlenk tube under Ar.…”