Syntheses, structures and magnetic properties of a family of metal carboxylate polymers viain situ metal–ligand reactions of benzene-1,2,3-tricarboxylic acid

Cocrystals of pyrazine and benzene polycarboxylic acids

The crystal structures of four cocrystals of pyrazine with benzene polycarboxylic acids were determined, namely pyrazine–phthalic (benzene-1,2-dicarboxylic) acid (1/1), C4H4N2·C8H6O4 (1), pyrazine–hemimellitic (benzene-1,2,3-tricarboxylic) acid (1/1), C4H4N2·C9H6O6 (2), pyrazine–hemimellitic acid–water (1/2/2), C4H4N2·2C9H6O6·2H2O (2a), and pyrazine–pyromellitic (benzene-1,2,4,5-tetracarboxylic) acid (3/1), 3C4H4N2·C10H6O8 (3). In all cases, infinite chains of alternating acid and base molecules, bonded by O—H...N hydrogen bonds, are formed. However, the details of the supramolecular structures are different. The additional carboxylic acid groups in the tri- and tetracarboxylic acids participate in hydrogen bonding with neighbouring acid molecules (in 2), water molecules, which makes the structure more complicated (in 2a), or with additional pyrazine molecules (in 3). π–π interactions between aromatic rings help organize the crystal architectures in all cases except for hydrate 2a. In that case, the hydrogen-bond-enriched structure enforces a disposition of the rings in which no stacking is observed. The Hirshfeld surface analysis allows better visualization of the differences between the structures by fingerprint plots in particular.

Tenacic Acids: A New Class of Tenacious Binders to Metal Oxide Surfaces

The backbone of 2-hydroxyisophthalic acid was identified as a potential metal oxide anchor because of the perfect alignment of all three of its donor groups for binding to inorganic surfaces. It can therefore be used in the design of organic linkers for metal oxide based hybrid materials. Optimized and scalable methods for the synthesis of 2-hydroxyisophthalic acid (1) and its 5-substituted derivatives: 5-bromo- (2), 5-sulfooxy- (3), 5-hydroxy- (4), and 5-PEG600 (5) are presented. Dynamic light scattering (DLS) demonstrated that compound 2 inhibits Fe(OH)3 precipitation when FeIII aqueous solutions are titrated with NaOH, while similar titrations in the presence of the structurally-related isophthalic and salicylic acids, both missing the third donor group, show turbidity at pHs as low as 2.3 and 3.5, respectively. The adduct synthesized from 4.5 nm γ-Fe2 O3 nanoparticles and 5 is water-, alcohol- and CH2 Cl2 -soluble, and forms stable aqueous colloids in the pH range of 4.4-8.7. Moreover, at a pH close to neutral these colloids survive at 100 °C, demonstrating the high practicality of 2-hydroxyisophthalic acid for nanoparticulate inorganic/organic hybrid material design.

The crystal structure of poly[tetraaqua-tris(μ2-2,6-di(1H-imidazol-1-yl)naphthalene-κ2 N:N′)-bis(thiophene-2,5-dicarboxylato-κ1 O)]dicobalt(II), C30H24CoN6O6S

C30H24CoN6O6S, monoclinic, P21/c (no. 14), a = 11.892(6) Å, b = 11.206(6) Å, c = 20.694(11) Å, β = 93.558(13)°, V = 2752(3) Å3, Z = 4, R gt(F) = 0.0413, wR ref(F 2) = 0.1030, T = 293(2) K.

Construction of magnet-type coordination polymers using high-spin {Ni4}-citrate cubane as secondary building units

A robust ferromagnetic secondary building unit based on {Ni₄}-citrate cubane is identified to be able to construct diverse structures while retaining the original magnetism.

Observation of allylic rearrangement in water-rich reaction

Allylic rearrangement was first observed in a hydrothermal reaction of cyclic dicarboxylic anhydride with different metal centres, which can be rationalised as an S_E1 mechanism via the isolation of two resonated intermediates and DFT calculations.

Effect of phenylacetic acid coligands on the structures and magnetic properties of azido-bridged copper(ii)-chain compounds

To investigate how the structures and magnetic properties of azido–copper(ii) chain compounds are influenced by substituents on the phenylacetic acid coligands, three new azido-bridged Cu(ii) compounds have been successfully obtained, and structurally and magnetically characterized.

Assembly of 1,2,3-benzenetricarboxylic acid and sliver(I) metal center to a novel 3D supramolecular framework: syntheses, structure and properties

The reaction of AgNO3, pyrazine (pyz) and 1,2,3-benzenetricarboxylic acid (H3btc) leads to a new 3D supramolecular architecture, namely {[Ag(H2btc)(pyz)]·(H2O)2}n (1), which has been characterized by IR spectroscopy, elemental analysis, thermogravimetry, photoluminescent and powder X-ray diffraction (PXRD). Compound 1 displays a 3D supramolecular network, which is built from cationic Ag-pyz chains and anionic [(H2btc)n·2H2O]- layers through the weak Ag⋯O interaction. Complex 1 exhibits photoluminesscence with an emission maximum at ca.391 nm upon excitation at ca. 241 nm.

catena-Poly[(chloridozinc)-μ-5-(1-methyl-1H-benzimidazol-2-yl-κN(3))-1,2,3-triazol-1-ido-κ(2)N(1):N(3)]

In the title complex, [Zn(C(10)H(8)N(5))Cl](n), the Zn(II) ion is four-coordinated by one Cl atom and three N atoms from two in situ-generated deprotonated 5-(1-methyl-1H-benzimidazol-2-yl-κN(3))-1,2,3-triazol-1-ide ligands in a slightly distorted tetra-hedral geometry. The Zn(II) ions are bridged by the ligands, forming a helical chain along [001]. C-H⋯N and C-H⋯Cl hydrogen bonds and π-π inter-actions between the imidazole rings [centroid-centroid distance = 3.4244 (10) Å] assemble the chains into a three-dimensional supra-molecular network.

catena-Poly[hexaaquamagnesium(II) [bis(μ3-5-nitro-2-oxidoisophthalato)dicopper(II)] dihydrate]

In the centrosymmetric dinuclear anions of the title bimetallic complex, {[Mg(H(2)O)(6)][Cu(2)(C(8)H(2)NO(7))(2)]·2H(2)O}(n), each Cu(II) ion is strongly coordinated by four O atoms in a distorted square-planar geometry. Two of these O atoms belong to phenolate groups and the other two to carboxylate groups from 5-nitro-2-oxidoisophthalate (L1) trianions, derived from 5-nitrobenzene-1,2,3-tricarboxylic acid (O(2)N-H(3)L). The phenolate O atoms bridge the two Cu(II) ions in the anion. In addition, each Cu(II) cation interacts weakly with a symmetry-related carboxylate O atom of an adjacent L1 ligand, giving a square-pyramidal coordination geometry. The copper residue forms a ladder-like linear coordination polymer via L1 ligands. The [Mg(H(2)O)(6)](2+) cations sit on centres of inversion. The polymeric anions, cations and free water molecules are self-assembled into a three-dimensional supramolecular network via O-H···O hydrogen bonds.