Structural comparison of group 7 tri­carbonyl complexes of 2-{[2-(1H-imidazol-4-yl)eth­yl]imino­meth­yl}-5-methyl­phenolate

Two tricarbonyl complexes of rhenium(I) and manganese(I) coordinated by the tridentate ligand 2-{[2-(1H-imidazol-4-yl)eth­yl]imino­meth­yl}-5-methyl­phenolate in a distorted octa­hedral environment are reported with inter­esting structural similarities. Hydrogen-bond inter­actions result in two-dimensional networks and π–π stacking for both structures.

Partial conversion of thio­amide into nitrile in a copper(II) complex of 2,6-di­acetyl­pyridine bis­(thio­semicarbazone), a drug prototype for Alzheimer's disease

The crystal structure of a copper(II) complex of 2,6-di­acetyl­pyridine bis­(thio­semicarbazone) displays partial conversion of a thio­amide group to nitrile. The compound formation is correlated to its potential as a therapeutic tool for Alzheimer's disease and other neurodegenerative diseases.

The crystal structure, luminescence and nitro­benzene-sensing properties of a two-dimensional Mn^II coordination polymer based on 2,6-bis­(imidazol-1-yl)pyridine

A two-dimensional Mn^II coordination polymer, obtained by the self-assembly reaction of Mn(ClO₄)₂·6H₂O, NH₄SCN and bent 2,6-bis­(imidazol-1-yl)pyridine, features a unique two-dimensional (4,4) network with one-dimensional channels. The compound shows a strong luminescence emission and is highly sensitive for nitro­benzene detection.

Polymorphism of NaVO₂F₂: a P2₁/c superstructure with pseudosymmetry of P2₁/m in the subcell

The determination of space groups remains problematic in some special cases. A systematic investigation reveals that NaVO₂F₂ exists in at least four polymorphs, i.e. P2₁, P2₁/m, P2₁/c and one or more low-temperature ones. Subtle changes (e.g. atomic shifts and the ordered or partially ordered distribution of atoms) in crystals may lead to different space groups. These subtle changes are often not detectable with the popular computer programs when they fall within the default distance tolerances.

The first example of a two-coordinated Au^I atom bonded to an Fe^II atom and an N-heterocyclic carbene (NHC) ligand

A binuclear iron–gold complex was prepared by the reaction of K[CpFe(CO)₂] (Cp is cyclo­penta­dien­yl) with (NHC)AuCl [NHC = 1,3-bis­(2,6-diiso­propyl­phen­yl)imidazol-2-yl­idene]. This is the first example of a two-coordinated Au atom bonded to an Fe and a C atom of an N-heterocyclic carbene.

Synthesis of di­thia­fulvene–quinone donor–acceptor systems: isolation of a Michael adduct

The reaction between p-benzo­quinone and a 1,3-di­thiole phospho­nium salt, deprotonated by lithium hexa­methyl­disilazide (LiHMDS), gave a product mixture from which the Michael adduct was isolated.

The structure of the first stable monosubstituted sulfur di­imide

The detailed structure of the first stable monosubstituted sulfur diimide, namely 4-(4-methylphenyl)-1,3-diaza-2,4-dithiabuta-1,2-diene, is reported. This structure is compared with the only other example of a monosubstituted sulfur diimide crystal structure published to date, and differences in bonding, conformation and packing are observed.

The exopolyhedral ligand orientation (ELO) in 3-(nitrato-κO)-3,3-bis­(tri­phenyl­phosphane-κP)-3-rhoda-1,2-dicarba-closo-dodeca­borane(11) di­chloro­methane 2.2-solvate

In 3-nitrato-3,3-bis­(tri­phenyl­phosphane)-3-rhoda-1,2-dicarba-closo-dodeca­borane(11), the nitrate ligand lies cis with respect to both cage C atoms. Accordingly, the compound displays a pronounced preferred exopolyhedral ligand orientation (ELO) which is traced to both the greater trans influence of the cage B over the cage C atoms and the greater trans influence of the tri­phenyl­phosphane ligands over the nitrate ligand.

One-dimensional deca­vanadate chains in the crystal structure of Rb₄[Na(H₂O)₆][HV₁₀O₂₈]·4H₂O

The crystal structure of an alkaline monoprotonated deca­vanadate hydrate was determined from single-crystal X-ray diffraction data. Structural relationships among protonated and deprotonated deca­vanadates with inorganic cations, including minerals of the pascoite group, are discussed.

A two-dimensional layered Cd^II coordination polymer with a three-dimensional supra­molecular architecture incorporating mixed multidentate N- and O-donor ligands

The coordination polymer formed from the reaction of Cd(Ac)₂ with succinic acid and 1-[(1H-benzimidazol-2-yl)meth­yl]-1H-tetra­zole in water–methanol solution displays a two-dimensional structure and inter­molecular hydrogen-bonding inter­actions play an important role in the formation of the polymer structure. In addition, the polymer exhibits a strong fluorescence emission in the solid state at room temperature.

A sterically congested cis-stilbene and its phospho­nium salt precursor

When crystallized in the presence of air, anhydrous triphenyl(2,4,5-trimeth­oxybenzyl)phospho­nium chloride forms a stoichiometric monohydrate, in which the components are linked into sheets by a combination of O—H⋯Cl and C—H⋯O hydrogen bonds. The Wittig reaction of the anhydrous salt with substituted benzaldehydes gives a series of stilbenes and the mol­ecular geometry of (Z)-2,2′,4,4′,5,5′-hexa­meth­oxy­stilbene provides evidence for steric congestion, leading to a nonplanar central alkene unit.

Synthesis, structure and properties of a new three-dimensional inter­penetrated metal–organic framework with 3,3′-azodi­benzoic acid (H₂azdc) and 1,4-bis­(1H-imidazol-1-yl)butane (bimb): {[Cd(azdc)(bimb)₂]·H₂O}_n

A threefold inter­penetrated three-dimensional framework with α-Po topology composed of cadmium(II) and 3,3′-(diazenedi­yl)di­ben­zoate and 1,4-bis­(1H-imidazol-1-yl)butane ligands was synthesized and characterized. The complex was found to exhibit a blue fluorescence in the solid state.

A structural study of (1RS,2SR,3RS,4SR,5RS)-2,4-di­benzoyl-1,3,5-tri­phenyl­cyclo­hexan-1-ol chloro­form hemisolvate and (1RS,2SR,3RS,4SR,5RS)-2,4-di­benzoyl-1-phenyl-3,5-bis­(2-meth­oxy­phen­yl)cyclo­hexan-1-ol

The crystal structures of two 1,3,5-tri­aryl-2,4-dibenzoyl­cyclo­hexan-1-ols have been confirmed by NMR studies. One diastereomer of one of the cyclo­hexa­nols possesses the same configuration as the other cyclo­hexa­nol. In both cyclo­hexa­nols, the cyclo­hexane ring adopts a chair conformation with all bulky groups (benzoyl, phenyl and 2-meth­oxy­phen­yl) in equatorial positions.

The structures of the isomorphous potassium and rubidium salts of 4-nitro­benzoic acid and an overview of the metal complex stereochemistries of the alkali metal salt series with this ligand

The structures of the isomorphous K and Rb coordination complexes with 4-nitro­benzoic acid have been determined and they are included in a brief review of the overall metal stereochemical features among the alkali metal complex series with this acid.

Grown from lithium flux, the ErCo₅Si_3.17 silicide is a combination of disordered derivatives of the UCo₅Si₃ and Yb₆Co₃₀P₁₉ structure types

A ternary hexa­erbium triacontacobalt enneakaideca­silicide, ErCo₅Si_3.17, crystallizes as a combination of disordered variants of the hexa­gonal UCo₅Si₃ (P6₃/m) and Yb₆Co₃₀P₁₉ (P) structure types and is closely related to the Sc₆Co₃₀Si₁₉ and Ce₆Rh₃₀Si₁₉ types. Crystallochemistry analysis and the data from electronic structure calculations (TB–LMTO–ASA) suggest that the Er atoms form positively charged cations which compensate the negative charge of the [Co₁₂Si₉]^m− polyanions.

Two reversible enanti­otropic phase transitions in a penta­coordinate silicon complex with an O,N,O′-tridentate valinate ligand

Chiral dimeth­yl[N-(4-oxidopent-3-en-2-yl­idene)valinato-κ³O,N,O′]silicon(IV) undergoes two sharp enanti­otropic phase transitions upon cooling. Both phase transitions are fully reversible and correspond to order–disorder transitions of the isopropyl group of the valine unit in the ligand backbone. The phase transitions presented here raise questions, since they do not fit into the rules of group–subgroup relationships.