Architectures and DFT calculations of polyrotaxane MOFs with nanoscale macrocycles

Abstract

Polyrotaxane metal-organic frameworks (PMOFs) have attracted considerable attention due to their aesthetic topologies and potential biological applications. In this paper, we synthesized two kinds of hcb networks with nanoscale macrocycles. The hcb networks interlocked with each other in inclined and parallel interlocking modes respectively, giving rise to two new PMOFs, {[Ni(DPDBT)(bdc)]·(H2O)2}n (1) and {[Zn(DPDBT)(fuma)]}n (2). DFT calculations are used to elucidate why the inclined interlocking mode is preferential for 1 while the parallel interlocking mode is preferential for 2. The networks of 1 with a parallel interlocking mode, as well as 2 with an inclined interlocking mode, were simulated. The total energies of the parallel and inclined structures proved that the as-synthesized interlocking modes of 1and 2 are more stable. Moreover, photophysical properties and thermal analyses of related ligands and complexes are investigated and discussed in detail.

Synthesis, structures and magnetic properties of isoreticular polyrotaxane-type two-dimensional coordination polymers

“…This polyrotaxane entanglement has been observed in several 2D structures before. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] By virtue of X-ray crystallographic symmetry, bpy ligand is at the centre of this square cavity. The total potential solvent accessible area volume as calculated by PLATON in 1 is 288.3Å 3 which is 7.6% of the unit cell volume 3809.5Å 3 despite two-fold interpenetration.…”

“…[8][9][10][11][12][13][14][15][16][17][18] For instance, the two-dimensional (2D) CPs containing polyrotaxane structures can be designed and constructed from bent dipyridyl ligands and linear dicarboxylates or vice versa. [19][20][21][22][23][24][25] Recently, we reported several supramolecular isomers in polyrotaxane-type CPs of Zn(II) and Co(II) using a bent ligand, 4,4 0 -sulfonyldibenzoate (sdb, Scheme 1) and a long linear spacer ligand, 1,4-bis[2-(4 0 -pyridyl)ethenyl]benzene (bpeb). 26,27 The polyrotaxane-type Co(II) CPs show typically antiferromagnetic behaviour due to the long spacer ligand bpeb which prevents the neighbouring paddlewheel Co(II) coming closer in the solid state structures.…”

Two-Dimensional Metal-Organic Framework Materials: Synthesis, Structures, Properties and Applications

“…also revealed a 2D honeycomb sheet with same polyrotaxane structure in which tetrahedral Zn­(II) centers coordinated to bmimbp in syn -conformation and rigid tbtpa with both syn – syn and anti – anti modes . Similar relevant examples displaying identical entangled form are provided in the literature. ,,− …”

“…As depicted in Figure d, two rods from inclined sheets (red and orange) passes through the highlighted blue loop on opposite sides, whereas rods of blue net on the other sides participate in rotaxane interactions with loops from green and pink inclined sheets. The MOFs [Cd 2 (L) 2 (1,4-bdc)­(NO 3 ) 2 ]·2DMF (L = 4-amino-3,5-bis­(4-imidazol-1-ylphenyl)-1,2,4-triazole); [Cd 4 (1,4-bix) 4 (bpea) 4 ]·4H 2 O and [Ni­(DPDBT)­(1,4-bdc)]·(H 2 O) 2 (DPDBT = 2,8-di­(pyridin-4-yl)­dibenzo­[b,d]­thiophene) feature this type of polythreading network in which bpea/1,4-bdc act as rods and 1,4-bix/L/DPDBT with curved geometries bridge Cd­(II) to form loops. ,, Additionally, Vittal et al . demonstrated parallel/diagonal inclined entanglement in polyrotaxane-based rectangular 2D sheet to form 3D structure in [Zn 2 (bpeb)­(sdb) 2 ] and [Co 2 (bpeb)­(sdb) 2 ]·0.5DMA·2H 2 O. , …”

Supramolecular Isomerism and Polyrotaxane-Based Two-Dimensional Coordination Polymers

“…Wheel-shaped cyclodextrins have been used to construct a variety of mechanically interlocked architectures including rotaxanes. , Correspondingly, wheels formed by two bent spacer ligands with two metal ions and axles made by linear spacer coligands have been used to assemble a variety of entangled structures including polyrotaxanes. − The two-dimensional (2D) coordination polymers (CPs) containing polyrotaxane structures can be designed and constructed from bent dipyridyl ligands and linear dicarboxylates or vice versa. − …”