Three new hexanuclear Fe(III) coordination wheels [Fe6Cl6(L1)6]·5(MeCN) (1), [Na0.5Fe6Cl6(L1)6](N3)0.5·4.5(MeCN) (2), and [Fe6Cl6(L2)6]·2(MeCN) (3) have been synthesized with new prepared amino-acetonitrile derivatives 2-[bis(2-hydroxyethyl)amino]acetonitrile hydrochloride (H2L1) and 3-[bis(2-hydroxyethyl)amino]propanenitrile hydrochloride (H2L2). They were structurally characterized by single-crystal X-ray diffraction. Mößbauer spectroscopy and magnetic susceptibility measurements indicate dominant antiferromagnetic behavior between the Fe(III) centers.

Abstract A new μ3-oxo trinuclear chromium(III) propionate cluster, [Cr3(μ3-O)(O2CCH2CH3)6(pyr)3]NO3·0.25(H2O) (1), has been synthesized by reaction of a μ3-oxo trinuclear chromium(III) propionate precursor [Cr3(μ3-O)(O2CCH2CH3)6(H2O)3]NO3 with a pyrazol ligand (pyr) and characterized by IR spectroscopy, single-crystal X-ray structure determination, and thermal analysis. Magnetic susceptibility and magnetization studies revealed antiferromagnetic exchange interactions within the trinuclear Cr(III) cluster (J = −11.9 cm−1) and determined the electronic ground state (S = ½) of the compound.

A benzohydrazone compound N'-(2-hydroxy-5-methoxybenzylidene)-4-dimethylaminobenzohydrazide (H2L) was prepared. Reaction of H2L and acetylhydroxamic acid (HAHA) with VO(acac)(2) in methanol gave complex [VOL(AHA)]. Both H2L and the oxovanadium complex were characterized by elemental analysis, IR and UV-Vis spectra, and single crystal X-ray diffraction. The benzohydrazone ligand, in its dianionic form, coordinates to V atom through the phenolate oxygen, imino nitrogen and enolate oxygen. The acetohydroxamic acid coordintes to V atom through the carbonyl oxygen and deprotonated hydroxyl oxygen. The V atom is in octahedral coordination. H2Lb HAHA and the oxoyanadium(V) complex were tested for their urease inhibitory activities. The inhibition rate at concentration of 100 mu mol.L-1 on Helicobacter pylori urease is 63% for the oxovanadium complex. The IC50 value for the complex is 45 mu mol.L-1. Molecular docking study was performed to study the inhibition. CCDC: 1042493, H2L; 905427, the complex.

A Mott-type semiconductor based on a compactly fused and partially oxidized electron donor-acceptor (D-A) molecule was recently prepared and identified to exhibit a large room-temperature conductivity of 2 S cm(-1) . In a marked contrast to the organic conductors characterized by relatively well decoupled and segregated uniform stacks of D and A moieties, the formally half-oxidized tetrathiafulvalene donors of the actual compound are organized in columnar π stacks only, whereby the coplanar electron-acceptor units, namely benzothiadiazole, are closely annulated along their ridges. Herein, we present a theoretical study that explores the electronic structure of this novel type of organic semiconductor. The highly symmetric-solid state material behaves as a one-dimensional electronic system with strong antiferromagnetic interactions (coupling constant>200 cm(-1) ). The unique shape and local dipole of this redox-active fused electron D-A molecule lays the basis for further investigations of the collective electronic structure, mainly in the function of different counterions embedded in the crystalline lattice.

The title compound, C21H33N3O3, is a tri-substituted cyclohexyloxy triazine. In the crystal, the triazine rings form (C3i-PU) Piedfort units. The inter-centroid distance of the π–π interaction involving the triazine rings is 3.3914 (10) Å. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming ribbons propagating along [1-10]. There are also weak C—H...N and C—H...O contacts present, linking inversion-related ribbons, forming a three-dimensional structure.

A large family of bifunctional 1,2,4-triazole molecular tectons (tr) has been explored for engineering molybdenum(VI) oxide hybrid solids. Specifically, tr ligands bearing auxiliary basic or acidic groups were of the type amine, pyrazole, 1H-tetrazole, and 1,2,4-triazole. The organically templated molybdenum(VI) oxide solids with the general compositions [MoO3(tr)], [Mo2O6(tr)], and [Mo2O6(tr)(H2O)2] were prepared under mild hydrothermal conditions or by refluxing in water. Their crystal structures consist of zigzag chains, ribbons, or helixes of alternating cis-{MoO4N2} or {MoO5N} polyhedra stapled by short [N-N]-tr bridges that for bitriazole ligands convert the motifs into 2D or 3D frameworks. The high thermal (235-350 °C) and chemical stability observed for the materials makes them promising for catalytic applications. The molybdenum(VI) oxide hybrids were successfully explored as versatile oxidation catalysts with tert-butyl hydroperoxide (TBHP) or aqueous H2O2 as an oxygen source, at 70 °C. Catalytic performances were influenced by the different acidic-basic properties and steric hindrances of coordinating organic ligands as well as the structural dimensionality of the hybrid.

The global zero-field splitting (ZFS) parameters of three, ferromagnetically coupled, (3)-(3)-[XO4](-) (X = Cl, Re) capped, manganese(III) oximate single-molecule magnets, [Mn3O(R-sao)(3)(2,4-bipyridine)(3)XO4] [X = Cl, R = Me, Et; X = Re, R = Me; Me-sao = 2-hydroxyphenylethanone oximate(2-)], with crystallographic trigonal symmetry were determined by use of inelastic neutron scattering and high-field/high-frequency electron paramagnetic resonance spectroscopy. ReO4- (OO ca. 1.7 angstrom) is larger than ClO4- (OO ca. 1.4 angstrom), which allows more parallel alignment of the local ZFS tensors. However, this chemical modification results in concomitant distortions in the equatorial ligand plane. Consistent parametrization of all spectroscopic data was achieved, and effective spin-reversal barriers determined from alternating current susceptibility data were shown to be in good accordance with the energy barriers deduced from spectroscopy.

Three new organic semiconductors, in which either two methoxy units are directly linked to a dibenzotetrathiafulvalene (DB-TTF) central core and a 2,1,3-chalcogendiazole is fused on the one side, or four methoxy groups are linked to the DB-TTF, have been synthesised as active materials for organic field-effect transistors (OFETs). Their electrochemical behaviour, electronic absorption and fluorescence emission as well as photoinduced intramolecular charge transfer were studied. The electron-withdrawing 2,1,3-chalcogendiazole unit significantly affects the electronic properties of these semiconductors, lowering both the HOMO and LUMO energy levels and hence increasing the stability of the semiconducting material. The solution-processed single-crystal transistors exhibit high performance with a hole mobility up to 0.04 cm(2)  V(-1)  s(-1) as well as good ambient stability.

Two new magnetic cluster-based 3D coordination polymers consisting of mu(3)-oxo-centered cationic homometallic [(Fe3O)-O-III-(O2CCMe3)(6)](+) or neutral heterometallic [(Fe2CoO)-Co-III-O-II(O2CCMe3)(6)] coordination clusters bridged by different N,N'-donor ligands into three-dimensional networks of {[Fe3O(O2CCMe3)(6)(4,4'-bpy)(1.5)](OH)center dot 0.75(CH2Cl2)center dot x(H2O)}(n) (1, x approximate to 8) and {[Fe2CoO-(O2CCMe3)(6)(bpe)(0.5)(pyz)]}(n) (2) (where 4,4'-bpy = 4,4'-bipyridine; bpe = 1,2'-bis(4-pyridyl)ethylene; pyz = pyrazine) have been prepared under solvothermal conditions. Single-crystal X-ray diffraction studies reveal the existence of a 6-fold interpenetrated network with rare (8,3)-c (etc) topology for 1 and a 3-fold interpenetrated network with (10,3)-b (ths) topology for 2. The interpenetration effectively results in very low BET surface areas, and the compounds have to be regarded as nonporous. Magnetic studies of 1 and 2 point to both ferro- and antiferromagnetic intra- and intercluster exchange interactions between the isotropic Fe-III and the strongly anisotropic Co-II spin centers. Fe-57 Mossbauer spectroscopy confirms the uniform ferric (+III) valence state in both 1 and 2, and low-temperature data for 1 point toward distinct hyperfine fields for the Fe sites.

A tetrathiafulvalene (TTF)-fused piazselenole as a novel redox-active and fluorescent probe for highly sensitive determination of physiological thiols is presented.

A compact and planar donor-acceptor molecule 1 comprising tetrathiafulvalene (TTF) and benzothiadiazole (BTD) units has been synthesised and experimentally characterised by structural, optical, and electrochemical methods. Solution-processed and thermally evaporated thin films of 1 have also been explored as active materials in organic field-effect transistors (OFETs). For these devices, hole field-effect mobilities of μFE = (1.3±0.5)×10(-3) and (2.7±0.4)×10(-3)  cm(2)  V s(-1) were determined for the solution-processed and thermally evaporated thin films, respectively. An intense intramolecular charge-transfer (ICT) transition at around 495 nm dominates the optical absorption spectrum of the neutral dyad, which also shows a weak emission from its ICT state. The iodine-induced oxidation of 1 leads to a partially oxidised crystalline charge-transfer (CT) salt {(1)2I3}, and eventually also to a fully oxidised compound {1I3}⋅1/2I2. Single crystals of the former CT compound, exhibiting a highly symmetrical crystal structure, reveal a fairly good room temperature electrical conductivity of the order of 2 S cm(-1). The one-dimensional spin system bears compactly bonded BTD acceptors (spatial localisation of the LUMO) along its ridge.

Electron paramagnetic resonance (EPR) was applied to study rotational disorder of bis(mesitylene)vanadium (VBM, S = 1/2) in channels of 2,4,6-tris(4-Br-phenoxy)-1,3,5-triazine. To ensure a magnetically dilute system, decamethylbis(cyclopentadienyl) ruthenium was used as a main guest to fill the channels. X-ray diffraction confirmed inclusion formation, resulting in an incommensurate host-guest system. EPR spectra were measured using prismatic single crystals oriented to have B-o either parallel to the channel axis c or at any angle in between c and the perpendicular direction. Temperature-dependent spectra were recorded down to 80 K. The analysis revealed two types of paramagnetic guest entities, i.e. VBM (I) and VBM (II). Both showed dynamical effects due to a reorientational motion. VBM (I) is confined to show a molecular axis z distributed around c by a small angle (+/- 1.25 degrees), whereas for VBM (II) the distribution is completely disordered. The reorientational motions are frozen at low temperature giving for VBM (II) a powder-like EPR spectrum. Analysing EPR intensities allowed us to conclude that the ratio of (I)/(II) species is of the order of 1.5.

A tandem directed metalation has been successfully applied to the preparation of thieno[2,3-f]benzofuran-4,8-dione, providing an efficient and facile approach to symmetrically and unsymmetrically functionalize the thieno[2,3-f]benzofuran core at the 2,6 positions as well as to introduce the electron-withdrawing or -donating groups (EWG or EDG) at its 4,8 positions. The presence of various functional groups makes late-stage derivatization attainable.

Electronic tuning effects of substituents at the 4- and 8-positions of benzothiadiazole (BTD) within the fused tetrathiafulvalene-BTD donor-acceptor dyad have been studied. The electron acceptor strength of BTD is greatly increased by replacing Br with CN groups, extending the optical absorption of the small dyad into the near-IR region and importantly, the charge transport can be switched from p-type to ambipolar behaviour.

A quinoxaline-fused tetrathiafulvalene (TTF) derivative 1 has been synthesized to form a compact and planar π-conjugated donor–acceptor (D–π–A) ensemble, and its single crystal structure has been determined by X-ray diffraction.

A molecular, porous crystalline material constructed from neutral helical coordination polymers incorporating manganese(II) ions and two types of bridging ligands, namely the deprotonated form of 2-hydroxy-5-methoxy-3-nitrobenzaldehyde (HL) and isobutyrate (iB(-)), has been obtained and structurally characterized. Structural analysis reveals that within the coordination polymer each benzaldehyde derivative ligates two manganese ions in 6-membered chelating rings, and the isobutyrate ligands cooperatively chelate either two or three manganese ions. The solid state assembly of the resulting polymeric chains of formula [Mn-4(L)(2)(iB)(6)](n) (1), described in the polar space group R3c, is associated with tubular channels occupied by MeCN solvent molecules (1 center dot xMeCN; x <= 9). TGA profiles and PXRD measurements demonstrate that the crystallinity of the solid remains intact in its fully desolvated form, and its stability and crystallinity are ensured up to a temperature of 190 degrees C. Gas adsorption properties of desolvated crystals were probed, but no remarkable sorption capacity of N-2 and only a limited one for CO2 could be observed. Magnetic susceptibility data reveal an antiferromagnetic type of coupling between adjacent manganese(II) ions along the helical chains with energy parameters J(1) = -5.9(6) cm(-1) and J(2) = 1.8(9) cm(-1).

The explorative lanthanide coordination chemistry of 4′,5′-bis-(propylthio)tetrathiafulvenyl[i]dipyrido[3,2-a:2′,3′-c]phenazine (TTF-dppz) is described. Thereby, four new Ln(III) complexes, [Ln(NO3)3(TTF-dppz)2] with Ln(III)=Nd (1), Eu (2), Gd (3), Tb (4), have been prepared and characterized. An X-ray crystallographic study of [Gd(NO3)3(TTF-dppz)2] (3) shows that the Gd(III) ion is coordinated to six oxygen atoms from three bidentate nitrate ligands and four nitrogen atoms from two bidentate TTF-dppz molecules forming a distorted bicapped square antiprism coordination geometry. The UV-vis spectra of the four Ln(III) complexes show very strong absorption bands in the UV region consistent with ligand centred electronic π-π* transitions and an intense broad absorption band in the visible region corresponding to a spin-allowed electronic π-π* 1ILCT transition from the TTF-dppz ligand. Upon coordination, the 1ILCT band of the free TTF-dppz ligand is bathochromically shifted. The electrochemical studies reveal that all complexes undergo two reversible oxidation and one (quasi)reversible reduction processes, ascribed to the successive oxidations of the TTF moiety and the reduction of the dppz unit, respectively. Moreover, the magnetic properties of complexes 3 and 4 are discussed.