Combining valproate and bipyridyl ligands to construct a 0D core‐shell Zn5(μ3‐OH)2 cluster and a 2D layered coordination network with a [Zn3(μ3‐OH)]2 SBU. Issue 9 (21st August 2020)

• Record Type: Journal Article
• Authors: Abu Ali, Hijazi; Darawsheh, Mohanad
• Is Part Of: Acta crystallographica. Volume 76:Issue 9(2020)
• Page Start: 897
• Page End: 906
• Publication Date: 2020-08-21
• Subjects: zinc cluster -- crystal structure -- 2D network -- core‐shell complex -- valproic acid -- metal‐organic; Crystallography -- Periodicals; Crystals -- Periodicals; 548.3
• DOI: 10.1107/S2053229620011262
• Languages: English
• ISSNs: 2053-2296

Abstract

Abstract : The self‐assembly of a branched short‐chain fatty acid (valproic acid) and Zn ions in the presence of bipyridine ligands generates a core‐shell‐like 0D Zn5 (μ3 ‐OH)2 cluster and a 2D layered coordination network with a [Zn3 (μ3 ‐OH)]2 secondary building unit. The branched alkyl chain of the acid serves as protection for the cores or layers of metal atoms. Abstract : Starting from the proposed zinc carboxylate cluster tetrakis(μ‐2‐propylpentanoato)dizinc(II), Zn2 (μ2 ‐valp)4 (I ), of valproic acid, a branched short‐chain fatty acid, and bipyridine ligands, two new mixed‐ligand coordination compounds, namely, bis(2, 2′‐bipyridine)di‐μ3 ‐hydroxido‐hexakis(μ‐2‐propylpentanoato)bis(2‐propylpentanoato)pentazinc(II), [Zn5 (C8 H15 O2 )8 (OH)2 (C10 H8 N2 )2 ] (II ), and poly[[bis(μ‐4, 4′‐bipyridine)di‐μ3 ‐hydroxido‐octakis(μ‐2‐propylpentanoato)bis(2‐propylpentanoato)hexazinc(II)] dimethylformamide disolvate], {[Zn6 (C8 H15 O2 )10 (OH)2 (C10 H8 N2 )2 ]·2C3 H7 NO} n (III ), were synthesized. Compound II is a core‐shell‐type zero‐dimensional discrete Zn5 (μ3 ‐OH)2 metal–organic cluster with Zn ions in double‐triangle arrangements that share one Zn ion coincident with an inversion centre. The cluster contains three crystallographically non‐equivalent Zn ions exhibiting three different coordination geometries (tetrahedral, square pyramidal and octahedral). The cluster cores are well separated and embedded in a protective shell of the aliphatic branched short chains of valproate. As a result, there is no specific interaction between the discrete clusters. Conversely, compound III, a 2D layered coordination network with a secondary building unit (SBU), is formed by Zn6 (μ3 ‐OH)2 clusters exhibiting a chair‐like hexagonal arrangement. This SBU is formed from two Zn3 (μ3 ‐OH) trimers related by inversion symmetry and connected by two syn–anti bridging carboxylate groups. Each SBU is connected by four 4, 4′‐bipyridine ligands producing a 6 3 ‐hcb net topology. 2D coordination layers are sandwiched within layers of dimethylformamide molecules that do not interact strongly with the network due to the hydrophobic protection provided by the valproate ligands.