An acyl­amide metal–organic framework with an unprecedented four-connecting trinodal topology and amide oxygen coordination

A three-dimensional Zn^II coordination polymer with bridging benzene-1,4-di­carboxyl­ate and N¹,N³,N⁵-tris­[(pyridin-3-yl)meth­yl]benzene-1,3,5-tricarboxamide ligands is characterized by a rare (4,4,4)-connected (4.6².7².8)(4.6².7³)(4².6².7²) topology. The tricarboxamide ligand adopts an unprecedented tetra­dentate coordination mode, with one carboxamide O atom participating in the coordination.

The three-dimensional hydrogen-bonded structures in the ammonium and sodium salt hydrates of 4-amino­phenyl­arsonic acid

In the hydrated ammonium salt of 4-amino­phenyl­arsonic acid (p-arsanilic acid), the ammonium cations, arsonate anions and water mol­ecules inter­act through inter-species N—H⋯O hydrogen bonds to arsonate and water, and water O—H⋯O hydrogen bonds, giving the common two-dimensional layers lying parallel to (010), which are expanded into three-dimensions through the amine group. The sodium salt is a one-dimensional coordination polymer with water bridges generating chains extending along c and extensive inter-chain O—H⋯O and N—H⋯O hydrogen-bonding inter­actions linking these chains, giving an overall three-dimensional structure.

Crystal chemistry of anion-excess ReO₃-related phases. III.

The crystal structure of the high-pressure form of zirconium tetra­fluoride, γ-ZrF₄, is described. It is compared with other ionic MX₄ structure types.

Bis(pyrene)metal complexes of vanadium, niobium and titanium: isolable homoleptic pyrene complexes of transition metals

The first isolable homoleptic pyrene transition metal complexes are presented. In each case, the pyrene ligands are parallel and sandwich the transition metals in one of two possible inversion-related sites.

A candidate for a single-chain magnet: [Mn₃(OAc)₆(py)₂(H₂O)₂]_n (OAc is acetate and py is pyridine)

[Mn₃(OAc)₆(py)₂(H₂O)₂]_n (OAc is acetate and py is pyridine), a candidate for a single-chain magnet, is a true one-dimensional coordination polymer, in which the Mn^II centres form a zigzag chain along [010], based on trinuclear repeat units (Mn1⋯Mn2⋯Mn2′). The structural features are compatible with a single-chain magnet behaviour, as confirmed by preliminary magnetic studies.

Niclosamide methanol solvate and niclosamide hydrate: structure, solvent inclusion mode and implications for properties

The crystal structure of niclosamide methanol solvate has continuous channels along the crystallographic a axis, providing a pathway for the removal of the solvent mol­ecules.

Two Zn^II coordination complexes assembled by tri­thio­cyanuric acid and two different N-donor auxiliary ligands

The assemblies of two Zn^II coordination complexes, one mononuclear and the other a one-dimensional chain polymer, based on trithiocyanuric acid and two different N-donor auxiliary ligands are reported. Three-dimensional supra­molecular networks arise through inter­molecular N—H⋯S and N—H⋯N hydrogen bonds.

The two-dimensional coordination polymer poly[di­aqua­(μ₂-1H-imid­azo[4,5-f][1,10]phenanthroline)-μ₄-sulfato-μ₃-sulfato-dicadmium(II)]

In the Cd^II coordination polymer formed by 1H-imidazo[4,5-f][1,10]phenanthroline (IP), sulfate and water ligands, there are two crystallographically independent Cd^II centres with different coordination geometries. The Cd^II ions are alternately bridged by O atoms from two sulfate ligands, forming one-dimensional chains, which are bridged by the IP ligands to form two-dimensional layers. These layers are linked by inter­molecular hydrogen bonds, leading to the formation of a three-dimensional supra­molecular network.

The low-temperature form of calcium gold stannide, CaAuSn

The low-temperature form of CaAuSn has an EuAuGe-type structure (space group Imm2), with a = 4.5261 (7) Å, b = 7.1356 (11) Å and c = 7.8147 (11) Å. This structure is one of the two parent structures of its high-temperature polymorph (ca 873 K), which is an inter­growth structure of the EuAuGe- and SrMgSi-type structures in a 2:3 ratio.

An unusual conformation of gabapentin (Gpn) in Pyr-Gpn-NH-NH-Pyr stabilized by weak inter­actions

An unusual trans–gauche (tg⁻) conformation of the gabapentin residue is stabilized by weak intra­molecular inter­actions in the crystal structure of Pyr-Gpn-NH-NH-Pyr monohydrate.

Packing forces in di­chlorido­bis­(3,5-di­phenyl-1H-pyrazole-κN²)cobalt(II) di­chloro­methane hemisolvate

In a cobalt(II) complex incorporating 3,5-diphenyl-1H-pyrazole and chloride ligands, the supra­molecular structure is supported by complementary hydrogen bonding between the pyrazole NH group and the chloride ligand of an adjacent mol­ecule, yielding a ten-membered hydrogen-bonded ring. Density functional theory (DFT) simulations suggest that the chelate undergoes a degree of conformational distortion from the lowest-energy geometry to allow for optimal hydrogen bonding in the solid state.

Distinguishing tautomerism in the crystal structure of (Z)-N-(5-ethyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl­idene)-4-methyl­benzene­sulfonamide using DFT-D calculations and ¹³C solid-state NMR

The crystal structure of (Z)-N-(5-ethyl-2,3-di­hydro-1,3,4-thia­diazol-2-yl­idene)-4-methyl­benzene­sulfonamide contains an imine tautomer, rather than the previously reported amine tautomer. The tautomers can be distinguished using dispersion-corrected density functional theory calculations and by comparison of calculated and measured ¹³C solid-state NMR spectra.

The effect of bromine scanning around the phenyl group of 4-phenyl­quinolone derivatives

In three quinolone compounds, the 1,4-di­hydro­pyridine (1,4-DHP) rings adopt flat-boat conformations which are bisected by the plane of the pseudo-axial brominated aryl ring. The cyclo­hexanone rings adopt an envelope conformation. In all three compounds, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into extended chains. Inter­molecular halogen bonding between Br and the ester carbonyl O atom is observed in two of the compounds.

Polymorphism of 2,5-[(di­phenyl­phosphan­yl)meth­yl]-1,1,2,4,4,5-hexa­phenyl-1,4-diphospha-2,5-dibora­cyclo­hexa­ne

In two polymorphs of the tetra­hydro­furan disolvate of 2,5-[(di­phenyl­phosphan­yl)meth­yl]-1,1,2,4,4,5-hexa­phenyl-1,4-diphospha-2,5-dibora­cyclo­hexane and a pseudo-polymorph of the toluene solvate, the crystal packings are significantly different, but, surprisingly, their mol­ecular conformations are the same.

A three-dimensional zinc-based coordination polymer built from 5-carboxyl­ato-1-carboxyl­ato­methyl-2-oxidopyridinium with a 4-connected sra topology

In a novel three-dimensional Zn^II coordination polymer prepared by the hydro­thermal assembly of Zn(CH₃COO)₂·2H₂O and 5-carb­oxy-1-(carb­oxy­methyl)pyridin-1-ium-2-olate (H₂ccop), the Zn^II atom adopts a five-coordinated distorted trigonal biyramidal geometry. The ccop²⁻ ligands adopt the same μ₄-bridging mode linking four Zn^II cations and giving rise to a three-dimensional framework with a 4-connected sra topology.

Three-dimensional hydrogen-bonded framework structures in flunarizinium nicotinate and flunarizinediium bis­(4-toluene­sulfonate) dihydrate

Hydrogen bonding in flunarizinium nicotinate and flunarizinediium bis­(4-toluene­sulfonate) dihydrate forms different three-dimensional framework structures.

Heterocyclic tautomerism: reassignment of two crystal structures of 2-amino-1,3-thia­zolidin-4-one derivatives

Two structures of 2-amino-1,3-thia­zolidin-4-one derivatives, deposited in the Cambridge Strutural Database (refcodes GACXOZ and HEGLUC), that undergo the phenomenon of proton amine–imine tautomerism are shown to exist in their crystal structures as the tautomer with the carbonyl–imine group in the five-membered heterocyclic ring and an exocyclic amine N atom, rather than the previously reported tautomer with a secondary amide group and an exocyclic imine N atom.

Electronic structure, novel synthesis, and O—H⋯O and C—H⋯O inter­actions in two 6-oxo­piperidine-2-carb­oxy­lic acid derivatives

Two compounds containing heterocyclic piperidine rings have been prepared via a novel synthesis and characterized. Both structures have similar piperidine ring conformations, i.e. close to a half-chair.

Topological analysis of the three-dimensional coordination polymer poly[(μ₄-azido)[μ₄-5-(pyridin-4-yl)tetra­zolido]disilver(I)]

A topological analysis of a new three-dimensional pyridinyl­tetra­zolide silver complex indicates that its three-dimensional network can be described as a new kind of 4,4,4,4-connected network with the Schläfli symbol (4.8⁵)(4².8⁴)(4³.8³)₂.

Homoleptic 2,2′-bi­pyridine metal­ates(–I) of iron and cobalt, one cocrystallized with an anthracene radical anion and the other with neutral anthracene

The first structures of homoleptic 2,2′-bi­pyridine metalates(–I) of iron and cobalt are shown to have reduced bi­pyridine ligands. One structure is cocrystallized with an anthracene radical anion, while the other is cocrystallized with neutral anthracene.

Response to Heterocyclic tautomerism: reassignment of two crystal structures of 2-amino-1,3-thiazolidin-4-one derivatives by Gzella et al. (2014)

Response to Gzella et al. (2014). Acta Cryst. C70, 812–816.