Diamagnetic π-Dimers of the [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl Radical Anion in the Crystalline State: Preparation and X-ray Crystal Structure of a [(Me2N)2CC(NMe2)2]2+[(C2N4S2)2]2– Salt

A Sterically Hindered Derivative of 2,1,3-Benzotelluradiazole: A Way to the First Structurally Characterised Monomeric Tellurium-Nitrogen Radical Anion

Interaction of the tetradentate redox-active 6,6'-[1,2-phenylenebis(azanediyl)]bis(2,4-di-tert-butylphenol) (H₄ L) with TeCl₄ leads to neutral diamagnetic compound TeL (1) in high yield. The molecule of 1 has a nearly planar TeN₂ O₂ fragment, which suggests the formulation of 1 as Te^II L^2- , in agreement with the results of DFT calculations and QTAIM and NBO analyses. Reduction of 1 with one equivalent of [CoCp₂ ] leads to quantitative formation of the paramagnetic salt [CoCp₂ ]⁺ [1]^.- , which was characterised by single-crystal XRD. The solution EPR spectrum of [CoCp₂ ]⁺ [1]^.- at room temperature features a quintet due to splitting on two equivalent ¹⁴ N nuclei. Below 150 K it turns into a broad singlet line with two weak satellites due to the splitting on the ¹²⁵ Te nucleus. Two-component relativistic DFT calculations perfectly reproduce the a(¹⁴ N) HFI constants and A_∥ (¹²⁵ Te) value responsible for the low-temperature satellite splitting. Calculations predict that the additional electron in 1^.- is localised mainly on L, while the spin density is delocalised over the whole molecule with significant localisation on the Te atom (≥30 %). All these data suggest that 1^.- can be regarded as the first example of a structurally characterised monomeric tellurium-nitrogen radical anion.

Design, synthesis and isolation of a new 1,2,5-selenadiazolidyl and structural and magnetic characterization of its alkali-metal salts

A new electron acceptor is synthesized and reduced into its radical-anion isolated in the form of two salts with different structures and magnetic properties.

Breathing some new life into an old topic: chalcogen-nitrogen π-heterocycles as electron acceptors

Recent progress in the design, synthesis and characterization of chalcogen-nitrogen π-heterocycles, mostly 1,2,5-chalcogenadiazoles (chalcogen: S, Se and Te) and their fused derivatives, possessing positive electron affinity is discussed together with their use in preparation of charge-transfer complexes and radical-anion salts-candidate building blocks of molecule-based electrical and magnetic functional materials.

Antituberculosis, Antifungal and Photoluminescence Studies on a Mn(II)–Neocuproine Complex

The complex [Mn(Me2phen)(H2O)3(MeOH)][NO3]2, (Me2phen = 2,9-dimethyl-1,10-phenanthroline, neocuproine) has been prepared. Structural studies show that the [Mn (Me2phen) (H2O)3(MeOH)] cation is a six coordinate octahedral species with bidentate Me2phen and monodentate water and methanol ligands. The water molecules are hydrogen bonded to a Me2phen free ligand, which is co-crystallised in a position adjacent to the Mn complex. Face-to-face π···π stacking interactions between coordinated and free Me2phen ligand molecules generate an efficient parallel packing system in the complex, which also shows antituberculosis and antifungal activity. Photoluminescence properties are also reported.