Reversible Transformation between Cubane and Stairstep Cu₄I₄ Clusters Using Heat or Solvent Vapor

Abstract

The controlled self-assembly of CuI and an asymmetric ligand with mixed N/S donors, 2-(tert-butylthio)-N-(pyridin-3-yl)acetamide (L), afforded three Cu(I) coordination polymers (CPs), [Cu4I4L2(MeCN)2]n (1), [Cu4I4L2]n (2), and {[Cu4I4L2]⋅MeOH}n (3). X-ray analyses showed that CPs 1-3 are supramolecular isomers with 1, 2, and 3D structures, respectively. CP 1 adopts a stairstep Cu4I4 cluster, whereas CPs 2 and 3 are composed of cubane-like Cu4I4 clusters. Crystal-to-crystal transformations of 1 to 2 and 3 showed reversible transformations between different Cu4I4 clusters using heat or solvent (acetonitrile or methanol) vapor. CP 2 was reversibly transformed to 3 by the addition of methanol and heat. Therefore, the transformations between supramolecular isomers 1, 2, and 3 are completely reversible.

Designs of 3-Dimensional Networks and MOFs Using Mono- and Polymetallic Copper(I) Secondary Building Units and Mono- and Polythioethers: Materials Based on the Cu–S Coordination Bond

“…Despite MOF's are being investigated, none of the studies alluded to catalytic properties, one of the driving forces in designing such materials. The reason clearly stems from the fragility of these frameworks as some reports have shown that exchanging solvent crystallization molecules can induced a change in dimensionality [46], or simply decompose at low temperature (see [Cs[Cu 5 I 6 (L13) 2 ] n ), 169°C) [56]. Therefore, the mono-and dithioether assembling ligands are not appropriate for such endeavour.…”

“…When L5 is reacted with CuI in a MeOH/MeCN mixture, a 3D CP of formula [(Cu 4 I 4 )(L5) 2 •MeOH] n is obtained [46]. X-ray crystallography (CSD KOXMAN) reveals the presence of the strongly luminescent Cu 4 I 4 cubane as SBU's and one MeOH crystallization molecule (Fig.…”

A two-dimensional copper(I) coordination polymer based on 1-[2-(cyclohexylsulfanyl)ethyl]pyridin-2(1H)-one

“…In addition, the arrangement of donor atoms in the ligands may affect both the structures of the complexes and their physical properties. Copper(I) complexes of flexible ligands with N/S donor atoms have been studied (Jeon et al, 2014;Cho et al, 2015). Mechanochromism, vapochromism and solvatochromism of such complexes have also been reported (Kwon et al, 2017;Kang et al, 2015;Kim et al, 2013).…”

Crystal structure ofN-[2-(cyclohexylsulfanyl)ethyl]quinolinic acid imide

“…In addition, it is expected that various metal complexes may be formed because they are composed of N/S-donor atoms. In particular, our group reported copper(I) coordination polymers with N/S-donor-atom ligands, which showed their various luminescence and reversible/irreversible structural transformations (Jeon et al, 2014;Cho et al, 2015). As part of our ongoing studies in this area, we designed and synthesized a new N/S-donor ligand, namely N-[2-(cyclohexylsulfanyl)ethyl]quinolinic acid imide, which was prepared from the reaction of quinolinic anhydride with 2-(cyclohexylsulfanyl)ethylamine.…”