A one-dimensional chloride-bridged Pt^II/Pt^IV mixed-valence complex with a 4-[(4-hy­droxy­phenyl)diazen­yl]benzene­sulfonate counter-ion

In a linear chain structure composed of square-planar [Pt(en)₂]²⁺ (en is ethyl­ene­di­amine) and elongated octa­hedral trans-[PtCl₂(en)₂]²⁺ cations, the components are stacked alternately, bridged by Cl atoms, along the b axis. The structural parameter indicating the mixed-valence state of the Pt atom, expressed by δ = (Pt^IV—Cl)/(Pt^II⋯Cl), is 0.643.

A new route for the synthesis of phosphate esters: 2,2′-[benzene-1,2-diylbis(­oxy)]bis­(5,5-di­methyl-1,3,2-dioxaphosphinane) 2,2′-dioxide

A new route for the synthesis of phosphate esters with a retained six-membered ring produced 2,2′-[benzene-1,2-diylbis(­oxy)]bis­(5,5-dimethyl-1,3,2-dioxaphosphinane) 2,2′-dioxide in which two 1,3,2-dioxaphosphinane groups are linked through a catechol group. The conformations about the two catechol O atoms are quite different.

Synthon preference in a hydrated β-resorcylic acid structure and its cocrystal with thymine

The crystal structure determinations of β-resorcylic acid hydrate and thymine–β–resorcylic acid hydrate were undertaken in order to study the synthon preference. In the former, an acid–acid homosynthon and in the latter an amide–acid heterosynthon are observed.

A novel crystal structure of {tris­[4-(1H-pyrazol-3-yl-κN²)-3-aza­but-3-en­yl]amine-κN}iron(II) bis­(tetra­fluorido­borate) methanol monosolvate featuring a low-spin configuration

The cocrystallized solvent has a marked influence on the spin-transition properties of {tris­[4-(1H-pyrazol-3-yl)-3-aza­but-3-en­yl]amine}­iron(II) bis­(tetra­fluorido­borate) in the solid state. In contrast to previously published structures showing only a high-spin configuration, the methanol solvate features a strictly low-spin configuration at 100 K.

Bis(2-{1-[(2,4,6-tri­methyl­phen­yl)imino]­eth­yl}pyrrol-1-ido-κ²N,N′)nickel(II): a supra­molecular structure formed by C—H⋯π(arene) hydrogen bonds

Molecules of a new nickel(II) complex of 2-[(2,4,6-tri­meth­ylphen­yl)­imino­eth­yl]­pyrrol-1-ide are linked into an extensive network by means of inter­molecular C—H⋯π(arene) hydrogen bonds in which every mol­ecule acts both as a hydrogen-bond donor and acceptor. The supra­molecular assembly takes the form of an infinite two-dimensional sheet.

A novel one-dimensional metal–organic framework with a μ-cyanido-argentate group: catena-poly[[(5,5′-di­methyl-2,2′-bi­pyridyl-κ²N,N′)silver(I)]-μ-cyanido-κ²N:C]

[Ag(CN)(5,5′-dmbpy)]_n (5,5′-dmbpy is 5,5′-dimethyl-2,2′-bipyridine) crystallizes in the monoclinic space group C2/c with the Ag^I cation on an inversion centre. Each Ag^I cation exhibits a distorted tetra­hedral geometry, generating a one-dimensional zigzag chain. These chains are linked together via weak nonclassical inter­molecular inter­actions, generating a two-dimensional supra­molecular network.

Five closely related 4-chloro-6,11-di­hydro-5H-benzo[b]pyrimido[5,4-f]azepines: similar mol­ecular structures but different supra­molecular assemblies

Five related benzo[b]pyrimido[5,4-f]azepine derivatives all exhibit similar mol­ecular structures containing a boat conformation for the azepine ring, but all five structures show a different range of direction-specific inter­molecular inter­actions and hence different patterns of supra­molecular assembly.

A new two-dimensional extended adenine and thio­phene­carboxyl­ate mixed-ligand zinc(II) complex: synthesis, structure, thermostability and luminescent properties

The structure of a new adenine-based Zn^II two-dimensional coordination polymer incorporating thio­phene-2,5-di­carboxyl­ate ligands exhibits in its packing two-dimensional (4,4) grid sheets parallel to the ab plane, featuring two distinct square cavities delimited by the two types of ligands and the Zn^II ions. The complex shows enhanced photoluminescence intensity compared to the free ligands.

Structural characterization of the aqua­porin inhibitor 2-nicotinamido-1,3,4-thia­diazole

Structural characterization of 2-nicotinamido-1,3,4-thia­diazole (TGN-020) was completed using X-ray crystallographic techniques and ¹H and ¹³C NMR spectroscopic assignments were made using 1D and 2D NMR methods. Parameters for blood–brain barrier permeability were also determined using computation methods.

Mometasone furoate revisited, or how did the hydrate get in the bottle?

A crystal harvested directly from a bottle of nasal spray, in which the active ingredient is delivered in the solid state and is stated to be crystals of the orthorhombic anhydride of mometasone furoate suspended in aqueous solution. Determination of the unit cell revealed that the crystal found in the bottle was, in fact, not the polymorph described in the product monograph, but rather the triclinic monohydrate.

A zwitterion produced by a strong intra­molecular N→B inter­action in 1-hy­droxy-2-(pyridin-2-yl­carbon­yl)benzo[d][1,2,3]di­aza­borinine

2-Acyl­ated 2,3,1-benzodi­aza­borines can display unusual structures and reactivities. The crystal structure analysis of the boron heterocycle obtained by condensing 2-formyl­phenyl­boronic acid and picolinohydrazide reveals it to be an N→B-chelated zwitterionic tetra­cycle. A favored yet reversible chelation equilibrium provides an explanation for the slow D₂O exchange observed for the OH resonance in the ¹H NMR spectrum.

Novel one- and two-dimensional Zn^II coordination polymers based on a versatile 3,6-bis­(pyridin-4-yl)phenanthrene-9,10-dione ligand

Two new Zn^II coordination polymers based on 3,6-bis­(pyridin-4-yl)phenanthrene-9,10-dione displaying different coordination modes feature one-dimensional zigzag chains connected by weak C—H⋯π and π–π inter­actions to form a two-dimensional network in one polymer, and a wave-like two-dimensional layered structure with helical chains in the other.

Oxidative degradation of the organometallic iron(II) complex [Fe{bis­[3-(pyridin-2-yl)-1H-imidazol-1-yl]methane}(MeCN)(PMe₃)](PF₆)₂: structure of the ligand decomposition product trapped via coordination to iron(II)

The structure of an iron(II) complex features coordination by an organic decomposition product, i.e. 1,1′-bis­(pyridin-2-yl)-2,2-bi(1H-imidazole), of a tetra­dentate N-heterocyclic carbene (NHC) ligand in an axial position. The decomposition product, a C—C-coupled bi­imidazole, is trapped by coordination to still-intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.

Structures and packing of ferrocenylmethyl methacrylate and ferrocene-1,1′-diylbis(methyl­ene) dimethacrylate

The mol­ecular and crystal structures of ferrocenyl derivatives with methyl methacrylate substituents in one and both of the cyclo­penta­diene rings are reported. C—H⋯O and C—H⋯π(ring) contacts stabilize both structures and the bis­(methyl methacrylate) compound displays unusual C—H⋯π(alkene) contacts.

Structural aspects of two α-dihydrazones displaying a complete survey of inter­molecular inter­actions

Two puzzling α-dihydrazones were obtained unexpectedly through an otherwise firmly established synthetic procedure aimed at the preparation of substituted pyrazoles. Possible reasons for this anomalous behaviour are analyzed. Weak inter­molecular inter­actions are responsible for the crystal stability, from which some unusual O⋯O contacts representing a special case of `electron donor–acceptor' (EDA) inter­actions stand out.

The first N-terminal unprotected (Gly-Aib)_n peptide: H-Gly-Aib-Gly-Aib-OtBu

The achiral N-terminal unprotected tetra­peptide H-Gly-Aib-Gly-Aib-OtBu forms no intra­molecular hydrogen bonds but does form eight inter­molecular hydrogen bonds with six symmetry-related mol­ecules. The backbone conformation starts in the right-handed helical region (and the left-handed helical region for the inverted mol­ecule) and reverses the screw sense in the last two residues.