Unique topological motifs in two Cd(ii)-coordination polymers: mutual-embedded 2D bilayers, 3D polythreaded structures, self-penetrated networks and 2D → 2D interpenetrated homochiral bilayers

Abstract

Two unique entangled Cd(ii) coordination polymers have been modulated by flexible/semi-rigid mixed-ligand systems.

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

“…56,72,460,463 Some recent examples featuring 2D to 2D parallel interpenetration are illustrated here. 496 Similarly, [Mn(NCS) 2 L 2 ] (L = bis(4pyridyl) substituted hydrazone derivatives) with triply interpenetrating corrugated 2D sheets are reported by Batten and co-workers. 497 Nagaraja et al also reported two 2D MOFs with sql net, [Zn 2 (muco) 2 (azopy) 2 ]•3DMF•2H 2 O and [Cd(muco)-(4bpdh)(H 2 O)], based on trans,trans-muconate dianion (muco) and different linkers 4,4′-bisazobipyridine (azopy) and 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4bpdh), respectively.…”

“…Three identical helical chains with the same chirality entangle with the triple-stranded helix of opposite chirality from the adjoining layers. Another 2D sql MOF [Cd­( m -pdoa)­(bpp)­(H 2 O)]·2H 2 O] ( m -H 2 pdoa = 1,3-phenylenedioxy diacetic acid) with unusual homochiral bilayers also display similar interpenetration . Similarly, [Mn­(NCS) 2 L 2 ] (L = bis­(4-pyridyl) substituted hydrazone derivatives) with triply interpenetrating corrugated 2D sheets are reported by Batten and co-workers …”

“…Li and co-workers reported an interesting 2D sql layered framework in [Cd 2 ( m -pdoa) 2 (dpa) 3 (H 2 O)] ( m -H 2 pdoa = 1,3-phenylenedioxy diacetic acid; dpa = 4,4′-dipyridylamine) anchored with alternating side arms. Such two oppositely oriented adjacent layers are mutually embedded to form a 2D embraced bilayer which further stack parallelly in ABABAB staggered fashion with dangling dpa groups projecting out from each sides of the sheet and generate a 3D polypseudorotaxane MOF . A similar 2D to 2D polypseudorotaxane MOF is noted in [Co­(CH 3 O-H 2 Ip)­(Bip)] (CH 3 O-H 2 Ip = 5-methoxylisophthalic acid; Bip = 3,5-bis­(imidazole-1-yl)­pyridine) .…”

Poly[(μ3-5-hydroxyisophthalato)[μ2-1,1′-(1,4-phenylene)bis(1H-imidazole)]copper]

“…A variety of metal-organic frameworks with intertesting structures have been reported based on 5-hydroxyisophthalic acid as this kind of carboxylate ligand offers six kinds of intricate connection models (Xu & Li, 2014). Supermolecules constructed by mixed ligands including carboxylate ligands and other N-donor molecules often show interesting networks compared with those compounds constructed by a single ligand (Xu et al, 2015). However, there are only a few examples reported which are based on OH-BDC and bib molecules (Wang et al, 2014;Liu & Guo., 2012;Su et al, 2015;Li et al 2015;Guo et al, 2013).…”

A new CdII coordination polymer with a self-penetrating architecture induced by the molecular conformation of a rigid bithiophene ligand

“…1) due to their structural complexity and functional properties (Martins et al, 2017;Gong et al, 2016;Shi et al, 2014;Yang et al, 2009Yang et al, , 2014Wu et al, 2011;Wang et al, 2007Wang et al, , 2008Liao et al, 2006). The favourite strategy for this issue is the use of conformationally kinked flexible ligands (Xu et al, 2015;Kim et al, 2014;Zhou et al, 2012;Wang et al, 2011;Hou et al, 2010). However, most of the designed entanglements fall into the interpenetrating category and only a few target nets were obtained unexpectedly.…”