Clive L. Oliver

Anionic zinc-trimesic acid MOFs with unusual topologies: reversible hydration studies.

The reaction of 1,3,5-benzenetricarboxylic acid (H(3)BTC) with ZnSO(4).6H(2)O in a DMF-water solution afforded two new metal-organic frameworks [Zn(6)(mu(3)-OH)(2)(BTC)(4)(DMF)(2.5)(H(2)O)(2)].[Zn(H(2)O)(3)(DMF)(3)].3.1H(2)O (1) and Zn(2)(HBTC)(BTC)(H(2)O)(3)].DMA.3H(2)O (2). Both compounds are thermally stable and can be prepared reproducibly. Rehydration experiments on compound 2 demonstrate reversible dehydration and rehydration while 1 rehydrates to a different crystalline material. Network analysis revealed a binodal (3,6)-net for 1 and a (3,5)-net for 2, both rare topologies.

A C-shaped p -sulfonatocalix[4]arene-based supermolecule exhibiting mutual-inclusion and bilayer insertion of dipicolinate

A p-sulfonatocalix[4]arene-based supermolecule, [Ce3(PDA)4(C4AS)2·13H2O](NO3)·25H2O 1 was prepared by slow evaporation of a solution of Ce(NO3)3·6H2O, 2,6-pyridinedicarboxylic acid (PDA) and pentasodium p-sulfonatocalix[4]arene salt. The molecular and crystal structure of 1 was determined by single crystal X-ray structural analysis and characterized by thermal methods (TG, DSC and hot-stage microscopy) and Hirshfeld analysis. The supermolecule is C-shaped with alternating calixarene and PDA ligands linked to three Ce(III) cations. The supermolecules exhibit mutual-inclusion via its PDA ligands with the remaining PDA ligands inserted into the calixarene bilayer. The bilayer consists of an “up–down” arrangement of calixarenes, with the inserted PDA ligands effecting a zig-zag propagation of the calixarenes within the bilayer.

In situ variable-temperature single crystal X-ray diffraction studies of the single-crystal-to-single-crystal dehydration and rehydration of a mixed-ligand 2D zinc metal–organic framework using trimesate and 4,4′-bipyridine-N,N′-dioxide as ligands

A mixed-ligand 2D MOF based on ZnSO4, trimesate and 4,4′-bipyridine-N,N′-dioxide was synthesized and characterized by variable-temperature X-ray diffraction, thermal analysis and infrared spectroscopy. It is the first crystal structure, let alone coordination polymer, containing both trimesate (or trimesic acid) and 4,4′-bipyridine-N,N′-dioxide. The 2D layers are arranged in a polar fashion with adjacent layers creating isolated cavities. Single crystal structure analyses of the same crystal at different temperatures confirm that dehydration occurs via a single-crystal-to-single-crystal transformation and yield insight into the order of water release upon dehydration. Rehydration of the 2D MOF occurred when exposed to air which was confirmed by thermogravimetric analysis and single crystal X-ray diffraction. Water vapour sorption experiments show a type I isotherm, typical of microporous materials.

A two-dimensional metal organic network with 1,3,5-benzenetricarboxylate and cobalt (II) ions: synthesis, structure and topology

Abstract We herein report the synthesis and structure of a two dimensional (2D) metal-organic coordination polymer (or metal-organic network) which extends in two dimensions via Co2+ and 1,3,5-benzenetricarboxylate ions. The hydrothermal reaction of (2R,2′R,2″R)-2,2′,2″-(benzenetricarbonyltris(azanediyl))tripropanoic acid (parent ligand) with cobalt nitrate in the presence of pyridine lead to the decomposition of the parent ligand producing 1,3,5-benzenetricarboxylate, which in turn reacted with cobalt ions to afford a 2D network [Co1.5(BTC3–)·(pyridine)3·(H2O)](H2O)0.26·(MeOH) (1). This network was characterized by single crystal X-ray diffraction and IR spectroscopy. The topological study indicated that the framework is a 3,4-connected binodal net.

Topological studies of three related metal-organic frameworks of GdIII and 5-nitroisophthalate.

The reaction of 5-nitroisophthalic acid (H(2)NIA) with Gd(NO(3))(3)·6H(2)O in DMF afforded three new metal-organic frameworks: [Gd(NIA)(1.5)(DMF)(2)]·DMF (I), [Gd(2)(NIA)(3)(DMF)(4)]·xH(2)O (II) and [Gd(4)(NIA)(6)(DMF)(5.5)(H(2)O)(3)]·4DMF·H(2)O (III). These compounds can be prepared through a variety of methods. Compounds (I) and (II) are more reproducibly formed than compound (III). Network analysis revealed (I) to have a (4(12).6(3))-pcu topology, while (II) displays a (4(2).8(4))(4(2).8(4))-pts topology. Compound (III) was found to present the uncommon 4,5,6T11 topological net, which combines aspects of both the pcu and pts topologies. The short symbol of this net is (4(4).6(2))(4(6).6(4))(2)(4(8).6(6).8).

Novel mixed 1D–2D lanthanide coordination polymers based on p -sulfonatocalix[4]arene and 4,4′-bipyridine- N , N ′-dioxide where p -sulfonatocalix[4]arene acts as a guest

Two novel mixed 1D–2D coordination polymers based on 2D [Ln(4,4′-bpdo)2(NO3)2(H2O)2]n+ sheets and 1D [Ln2(4,4′-bpdo)2(C4AS)(NO3)(H2O)9]n chains (Ln = Sm for 1 and Ln = Nd for 2) sustained by π⋯π interactions and lattice water facilitated hydrogen bonds have been established. The chains are arranged such that the p-sulfonatocalix[4]arene anions occupy the cavities of the 2D coordination polymer, and so act as guests rather than as hosts, which is their more usual role.

A Cd mixed-ligand MOF showing ligand-disorder induced breathing behaviour at high temperature and stepwise, selective carbon dioxide adsorption at low temperature

A mixed-ligand MOF [Cd(bpe)1.5(nbdc)]n·nDMF0.84 (1) has been synthesized where bpe = 1,2-bis(4-pyridyl)ethane, nbdc = 5-nitro-1,3-benzenedicarboxylate and DMF = N,N′-dimethylformamide. Single crystal X-ray diffraction studies reveal that the structure consists of 2-periodic, 3D nets which exhibit a square lattice motif and are catenated throughout the crystal structure. Variable-temperature single crystal X-ray diffraction studies show that the desolvation of the crystal upon heating is a single-crystal-to-single-crystal (SCSC) process accompanied by a change in the lattice constants, crystal system and space group. Disorder of the axial bpe ligands provide useful insight into the path of desolvation and also indicates that the relative void space at high temperature changes dynamically by nearly 600%, indicating a temperature-induced ‘breathing’ effect. Compound 1 shows appreciable sorption of carbon dioxide at 273 K and shows significantly increased sorption at 195 K with an associated change in the sorption profile, indicative of structural changes. The compound also adsorbed water vapour (298 K) to an appreciable amount.

Solid-state isolation of a unique, small-molecule, supra-heterodimer of large hexameric assemblies of C-methylcalix[4]resorcinarene

The well-known host molecule C-methylcalix[4]resorcinarene is shown to exist in two unique hexameric arrangements within the same crystal. These two hexameric assemblies are linked via a water molecule into a supra-heterodimer.

Crystal structures and hydrogen bond analysis of five amino acid conjugates of terephthalic and benzene-1,2,3-tricarboxylic acids

Four linear connecting amino acid derived ligands, 1–4, and one potentially three connecting, 5, were prepared by the reaction of the appropriate terephthaloyl dichloride or benzene-1,3,5-tricarbonyl trichloride with the methyl ester protected amino acid. Amino acids used here were alanine (1, 5), isoleucine (2), leucine (3) and valine (4). Crystalline forms of four amino acid substituted terephthalamides (2,2′-(terephthaloylbis(azanediyl))dipropanoic acid dihydrate 1; 2,2′-(terephthaloylbis(azanediyl))bis(3-methylpentanoic acid) monohydrate 2; 2,2′-(terephthaloylbis(azanediyl))bis(4-methylpentanoic acid) dihydrate 3; 2,2′-(terephthaloylbis(azanediyl))bis(3-methylbutanoic acid) dihydrate 4) and one benzene-1,3,5-tricarboxamide molecule (2,2′,2′′-((benzene-1,3,5-tricarbonyl)tris(azanediyl))tripropionic acid hemihydrate 5) were characterised and the single crystal structures were solved. All the compounds form hydrogen bonded 2D and 3D nets. Linear connecting amino acid derivatives can be categorised into three groups depending on the hydrogen bond patterns and final structures. Compounds 1 and 2 form 3D structures but the final structure is different due to the different hydrogen bond synthons. Compounds 3 and 4 are isostructural and form 2D hydrogen bonded structures while 5 forms a hydrogen bonded pcu-net. Intermolecular interactions have been analysed with Hirshfeld surfaces and graph set symbols.

Single-crystal-to-single-crystal transformation of the desolvation of a cyclotriveratrylene–acetonitrile inclusion complex via a gating mechanism with subsequent polymorphism

A cyclotriveratrelyne–acetonitrile inclusion complex is shown to undergo a single-crystal-to-single-crystal transformation upon desolvation to an intermediate phase and it is furthermore demonstrated that the preparation conditions may introduce polymorphism of the apohost. We characterised the as-synthesized and desolvated polymorphs using single crystal (polymorph 1) and powder X-ray diffraction, thermal analysis and gas sorption. Successive data collections on the as-synthesized crystal at 50 °C show that the rotation of a single, unique methoxy group of the host molecule may allow evacuation of solvent molecules from the seemingly non-porous crystal.