Coordination polymers utilizing N-oxide functionalised host ligands

Pyridyl functionalized host molecules are oxidized to their N-oxide analogues and form a series of coordination polymers and discrete complexes with transition metal cations. Complex {[Ag3(NMP)6(L1)2]·3(ClO4)}∞ where L1 = tris(isonicotinoyl-N-oxide)cyclotriguaiacylene, NMP = N-methylpyrrolidone, is a three-dimensional (3-D) 3,6-connected coordination polymer of pyrite-like (pyr) topology and features ligand unsupported argentophilic interactions, while two-dimensional (2-D) 3,6-connected coordination polymers with the rarely reported kagome dual (kgd) topology are found for [M(L1)2]2+ where M = Zn, Cd, Cu. Ligand L2 = tris(nicotinoyl-N-oxide)cyclotriguaiacylene forms a 2-D coordination polymer with 44 (sql) grid topology in complexes {[M(L2)2(DMF)2]·2ClO4·8(DMF)}∞ M = Cd or Cu, DMF = N,N′-dimethylformamide, and a double-linked chain structure in {[Co(L2)2(DMF)2]·2NO3·4(DMF)·H2O}∞, and both types of structure feature hand-shake self-inclusion motifs either within or between the polymers. 2-D coordination networks with 63 (hcb) topologies are found in complexes {[M(L3)(NO3)2]·2(DMF)}∞ (M = Cd, Zn) and {[Cu5(L3)2Cl10(NMP)4]}∞ where L3 = tris(2-pyridylmethyl)cyclotriguaiacylene, while [Ag2(L3)2(NMP)4]·2(BF4)·2(NMP) has a discrete dimeric structure which again shows hand-shake host–guest interactions supported by π–π stacking

Copper-Linked Rotaxanes for the Building of Photoresponsive Metal Organic Frameworks with Controlled Cargo Delivery

©2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted version of a Published Work that appeared in final form in Journal of the American Chemical Society. To access the final edited and published work see https://doi.org/10.1021/jacs.0c04477We have prepared a photoresponsive metal–organic framework by using an amide-based [2]rotaxane as linker and copper(II) ions as metal nodes. The interlocked linker was obtained by the hydrogen bond-directed approach employing a fumaramide thread as template of the macrocyclic component, this latter incorporating two carboxyl groups. Single crystal X-ray diffraction analysis of the metal–organic framework, prepared under solvothermal conditions, showed the formation of stacked 2D rhombohedral grids forming channels decorated with the interlocked alkenyl threads. A series of metal–organic frameworks differing in the E/Z olefin ratio were prepared either by the previous isomerization of the linker or by postirradiation of the reticulated materials. By dynamic solid state 2H NMR measurements, using deuterium-labeled materials, we proved that the geometry of the olefinic axis of the interlocked struts determined the obtention of materials with different independent local dynamics as a result of the strength of the intercomponent noncovalent interactions. Moreover, the usefulness of these novel copper-rotaxane materials as molecular dosing containers has also been assayed by the diffusion and photorelease of p-benzoquinone, evaluated in different solvents and temperatures

Remote Photoregulated Ring Gliding in a [2]Rotaxane via a Molecular Effector

A molecular barbiturate messenger, which is reversibly released/captured by a photoswitchable artificial molecular receptor, is shown to act as an effector to control ring gliding on a distant hydrogen-bonding [2]­rotaxane. Thus, light-driven chemical communication governing the operation of a remote molecular machine is demonstrated using an information-rich neutral molecule