Recently obtained bis-o-quinone with resorcinol as a bridge was utilized for synthesis of cobalt and nickel homobinuclear complexes. Two bis-o-semiquinonato metal fragments are situated co-facially to each other forming metallomacrocycle. Metals in both fragments bond diethyl ether solvate molecules externally as well as internally in the cell. At 100 K one of two metal atoms in the macrocycle is five-coordinated whereas the other one is six-coordinated due to internal solvent molecule. Heating to room temperature results in disordering of internal solvent molecule in two positions: coordinated to different nickel atoms. Variable temperature magnetic measurements indicate both complexes to be bis-o-semiquinonato anion-radical adducts of high spin metals with magnetic interactions inside of bis-o-semiquinonato units. Sign and energy of interactions depend on the coordination number of metal. Exchange interactions between units are weak. UV-Vis absorption spectrum is determined by ligands centered bands. CV indicates reversible reduction processes involving redox active dioxolene ligands.

A series of o -benzoquinones containing 2,4,4-trimethyl-2-pentyl ( tert -octyl) substituents were synthesized. The stability of the reduced forms of the synthesized o -quinones and the electron density distribution in the corresponding radical anion species were studied by cyclic voltammetry and EPR spectroscopy.

Monomeric and dimeric NHP complexes were prepared by reaction of N-heterocyclic diphospholene with Fe, Co and Ni carbonyls.

The effect of quasi-continuous (QC) equal-channel angular pressing (ECAP) in various pre-aged states on the structure formation and mechanical and functional properties of a hyper-equiatomic titanium nickelide (TiNi) shape memory alloy is studied. QC ECAP with a channel intersection angle of 110° is carried out at a temperature of 450 °C after aging for 1 and 5 h for three passes. To investigate the obtained structure and properties, the following research methods are applied: transmission electron microscopy, XRD analysis, calorimetric study, tension and hardness tests, and a special technique for the determination of functional properties. QC ECAP allows for the considerable refinement of structural elements and results in obtaining a mixed fine-grade structure, with structural elements of average sizes of 92 nm after pre-aging for 1 h and 115 nm after pre-aging for 5 h. Pre-aging for 5 h before QC ECAP, in combination with QC ECAP and post-deformation aging at 430 °C for 1 h, provides the best combination of mechanical and functional properties: a dislocation yield stress of 1410 MPa, ultimate tensile strength of 1562 MPa, and total recoverable strain of 11.6%. These values are comparable with the best results obtained for titanium nickelide and expand opportunities for the application of smart shape memory devices.

The oxidative addition of N , N '-disubstituted phenanthrenediimines to iron carbonyls was studied. The reactions of acceptor phenanthrenediimines with Fe 2 (CO) 9 give iron(I) tricarbonyl complexes with anion-radical forms of the ligands. The synthesized compounds were characterized by NMR and IR spectroscopy. The structures of the complex based on N , N '-bis(3-trifluoromethylphenyl)phenanthrenediimine and imidazol-2-one ligand was established by X-ray diffraction (XRD) (CIF files СCDC nos. 2173471 and 2173472, respectively).

In the present work, the possibility of applying severe torsion deformation (STD) to a bulk near-equiatomic NiTi shape memory alloy in order to accumulate super-high strain and improve mechanical and functional properties was studied. STD was performed using the multidirectional test system “BÄHR MDS-830” at a temperature of 500 °C (the upper border temperature for the development of dynamic polygonization) in 14 and 30 turns with accumulated true strain values of 4.3 and 9.1, respectively. Structural phase state and properties were studied using differential scanning calorimetry, X-ray diffractometry, transmission electron microscopy, hardness measurements, and thermomechanical bending tests. STD at 500 °C allowed for the accumulation of high strain without failure. As a result of STD in 30 turns, a submicrocrystalline structure with an average grain/subgrain size of about 500 nm was formed. This structure ensured the achievement of high maximum completely recoverable strain values of 6.1–6.8%. The results obtained show the prospects of applying severe torsion straining deformation to titanium nickelide in terms of forming an ultrafine-grained structure and high properties.

Two new cobalt bis -o- semiquinonato complexes, (Pyz-Phen)Co(3,6-DBSQ) 2 ( I ) and (Bpyz)Co(3,6-DBSQ) 2 ( II ) (Pyz-Phen = pyrazino[2,3-f][1,10]phenanthroline, Bpyz = bipyrazine, 3,6-DBSQ = 3,6-di- tert -butyl- o -benzoquinone radical anion), were synthesized. According to X-ray diffraction data, both complexes have a trigonal-prismatic geometry of the inner coordination sphere. The distribution of C–O and Co–O bond lengths, which reflects the valence state of the metal and the ligands, indicates that the complexes are formed by cobalt(II) surrounded by two semiquinone radical anions. The results of magnetochemical measurements show that the pyrazino[2,3-f][1,10]phenanthroline complex is a derivative of low-spin divalent cobalt, whereas its bipyrazine structural analogue is a high-spin cobalt(II) derivative.

Molecules with an extended conjugated π-electron system and a flat rigid topology have traditionally been considered as appropriate candidates for organic (semi-)conductors. With their potential for intramolecular charge transfer, these molecules can have bright prospects in optoelectronic device manufacturing. In this work we describe a novel bis-semiquinone complex of nickel and о-quinone annulated with a 1,3-dithiol-2-thiocarbonyl fragment and the peculiarities of thin-film deposition of this compound on different substrates. It is shown that a thin film can maintain the crystal structure of the original complex. A photovoltaic effect is detected in sandwich structures with an aluminum cathode. It is anticipated that further optimization of the structure of such sulfur-rich molecules will prodive solid-state ensembles with promising photovoltaic and/or photodetecting properties.

Ditopic di-o-quinone with a resorcinol bridge exhibits the ability to self-assemble in a reaction with copper, giving a cage-like binuclear complex that, due to the cofacially placed metal ions, is capable of encapsulation of different solvent molecules as guest ligands. Notably, the geometry of the internal cavity of this complex adjusts depending on the coordinating properties of the encapsulated molecule (mono- or bidentate). A feature of this species is that the cage-forming units are copper(II) bis-semiquinonate moieties, capable of undergoing ligand-centered redox transformations. Electrochemical and EPR spectroscopy studies showed that there is a channel for intramolecular electronic exchange interactions between the redox centres of the molecule.

In the present work, the possibility of manufacturing long-length TiNiHf rods with a lowered Hf content and a high-temperature shape memory effect in the range of 120–160 °C was studied. Initial ingots with 1.5, 3.0 and 5.0 at.% Hf were obtained by electron beam melting in a copper water-cooled stream-type mold. The obtained ingots were rotary forged at the temperature of 950 °C, with the relative strain from 5 to 10% per one pass. The obtained results revealed that the ingots with 3.0 and 5.0 at.% Hf demonstrated insufficient technological plasticity, presumably because of the excess precipitation of (Ti,Hf)2Ni-type particles. The premature destruction of ingots during the deformation process does not allow obtaining high-quality long-length rods. A long-length rod with a diameter of 3.5 mm and a length of 870 mm was produced by rotary forging from the ingot with 1.5 at.% Hf. The obtained TiNiHf rod had relatively high values of mechanical properties (a dislocation yield stress σy of 800 MPa, ultimate tensile strength σB of 1000 MPa, and elongation to fracture δ of 24%), functional properties (a completely recoverable strain of 5%), and a required finishing temperature of shape recovery of 125 °C in the as-forged state and of 155 °C after post-deformation annealing at 550 °C for 2 h.

The effect of a promising method of performing a thermomechanical treatment which provides the nanocrystalline structure formation in bulk NiTi shape memory alloy samples and a corresponding improvement to their properties was studied in the present work. The bi-axial severe plastic deformation of Ti-50.7at.%Ni alloy was carried out on the MaxStrain module of the Gleeble system at 350 and 330 °C with accumulated true strains of e = 6.6–9.5. The obtained structure and its mechanical and functional properties and martensitic transformations were studied using DSC, X-ray diffractometry, and TEM. A nanocrystalline structure with a grain/subgrain size of below 80 nm was formed in bulk nickel-enriched NiTi alloy after the MaxStrain deformation at 330 °C with e = 9.5. The application of MaxStrain leads to the formation of a nanocrystalline structure that is characterized by the appearance of a nano-sized grains and subgrains with equiaxed and elongated shapes and a high free dislocation density. After the MaxStrain deformation at 330 °C with e = 9.5 was performed, the completely nanocrystalline structure with the grain/subgrain size of below 80 nm was formed in bulk nickel-enriched NiTi alloy for the first time. The resulting structure provides a total recoverable strain of 12%, which exceeds the highest values that have been reported for bulk nickel-enriched NiTi samples.

Sterically hindered o-quinones functionalized with additional chelating groups were synthesized by the reaction of 3,6-di-tert-butyl-4,5-dichloro-o-benzoquinone with geminal dithiolates. The spin density distribution in reduced anion-radical derivatives of the new compounds was studied by EPR spectroscopy in order to reveal the possibilities of electronic communication between the coordination sites of the ditopic ligand. o-Quinones bearing the annulated thiete ring were synthesized and characterized.

The synthesis of four heteroligand o-semiquinonate cobalt complexes of bidentate 3-cyano- and 3-nitroformazans is described. All complexes are characterized by single-crystal X-ray diffraction and magnetic susceptibility measurements. The square-planar mono-o-semiquinonato-formazanate cobalt(II) complexes demonstrate diamagnetic properties due to strong intramolecular antiferromagnetic metal-ligand exchange. Magnetic properties of the six-coordinated bis-o-semiquinonato-formazanate cobalt(III) complexes indicate the domination of antiferromagnetic exchange interactions between unpaired electrons of o-semiquinonato ligands, and the inclusion of electron-withdrawing cyano and nitro groups at R-3 position of formazanate ligand leads to an increase of the energy of this exchange interaction.

A procedure has been developed for the annulation of a 2-(thi)oxo-1,3-dithiole-4,5-dithiolate fragment to 3,6-di-tert-butyl-o-benzoquinone. The resulting o-quinones have a significant asymmetry with respect to the plane of the chelate dioxolene site, which can be used in the targeted design of the coordination environment of metal ions in complexes. Isomeric manganese adducts containing dioxolene, carbonyl, and phosphine ligands, which differ in the location of the asymmetric o-quinone ligand, have been characterized by EPR spectroscopy.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The possibility of the application of nitronyl-nitroxide ligand (NIT) as a spin label for the study of the composition of transition metals complexes with M-NIT bonds by EPR spectroscopy was explored using PCP-pincer complexes of Pd and Ni as examples.

A series of novel dioxolene cobalt complexes with general formula (N-N)Co(3,6-diox)2 (where N-N = 2,2'- dipyridine (bpy) and 1,10-phenanthroline (phen), diox - mono-and dianionic forms of 3,6-di-isopropyl-o-ben-zoquinone (3,6-iPr-Q) and 3,6-di-cyclohexyl-o-benzoquinone (3,6-cHex-Q)) has been synthesized and charac-terized. The molecular structures of dipyridine adducts have been established by single crystal X-Ray structural analysis. Magnetic susceptibility measurements detect solid-state valence-tautomeric transformation occurring for complexes (phen)Co(3,6-iPr-SQ)(2) and (bpy)Co(3,6-cHex-SQ)(2). The phase transitions that accompany valence tautomeric transformation have been investigated by differential scanning calorimetry (DSC).

New heteroligand cobalt(III) bis-3,6-di- tert -butyl- o -benzosemiquinone complexes with p- tolyl-substituted formazan ligands Co(3,6-SQ) 2 L n (L 1 H is 1,5-diphenyl-3- p -tolylformazan ( I ), L 2 H is 1,3,5-tri- p -tolylformazan ( II ), and L 3 H is 3-nitro-1,5-di- p -tolylformazan ( III )) are synthesized and characterized. The molecular structures of compounds I , II , and III in the crystalline state are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2161722 ( I ), 2167094 ( II ), and 2167095 ( III )). According to the XRD results and magnetic and spectral measurement data, compounds I – III are complexes of low-spin cobalt(III) bound to two radical anion o- semiquinone ligands and one formazan anion. The magnetic behavior of the complexes in a temperature range of 2–300 K is characterized by intramolecular antiferromagnetic exchange interactions between the o- semiquinone ligands. The replacement of the phenyl substituents by p- tolyl groups in positions 1 and 5 of the diamagnetic formazanate ligand results in a significant enhancement of the exchange between the radical centers.

New triphenylantimony(V) catecholates 1–3 based on 3-formyl-substituted catechols L1-L3 have been synthesized and characterized (L1 is 2,3-dihydroxy-4,6-di‑tert‑butyl‑benzaldehyde, L2 is 2,3-dihydroxy-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene-1-carbaldehyde, and L3 is 2,3-dihydroxy-4,5,5,8,8-pentamethyl-5,6,7,8-tetrahydronaphthalene-1-carbaldehyde). The crystal structures of complexes 1, 2 have been determined by single-crystal X-ray analysis. It was found that the coordination sphere of the antimony atom is supplemented to 6 due to the intermolecular donor-acceptor bond of Sb…O with the formyl oxygen of the neighboring catecholate molecule. As a result, the formation of 1D-polymer structures for 1, 2 is observed.