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Abstract: New heterodinuclear pivalates (HPiv)6EuTb(Piv)6 (5) and (Phen)2EuTb(Piv)6 (6), where Piv=(CH3)3CCO2 −, the 2,2-dimethylpropanoate anion, and Phen=1,10-phenanthroline, were synthesized. The structures and compositions of the heterodinuclear molecules were determined by X-ray diffraction and based on magnetic measurements, inductively coupled plasma atomic emission spectrometry (ICP-AES) and the results of the research on the thermal decomposition and vaporization of the complexes. Under UV excitation, complex 6 exhibits luminescence and complete intramolecular excitation energy transfer to the Eu3+ ions involving singlet levels of the Phen ligand and f–f levels of the Tb3+ ions. [Copyright &y& Elsevier]

Abstract: The reaction of oxidovanadium sulfate VOSO4·3H2O with 4,4′-di-tert-butyl-2,2′-bipyridine (dtb-bpy) in methanol was found to give the complex (VO)2(μ2-SO4)2(dtb-bpy)2(CH3OH)2·4CH3OH (1). Single crystal X-ray diffraction reveals that molecule 1 is a centrosymmetric dimer consisting of two {VO(μ2-SO4)(dtb-bpy)(CH3OH)} moieties linked by two bridging sulfate anions. Each vanadium atom is in a distorted octahedral environment formed by two nitrogen and four oxygen atoms. The further reaction of an ethanolic solution of compound 1 with sodium pivalate in CH3CN produces the new dinuclear complex [(VO)2(μ2-O)2(μ2-SO4)(dtb-bpy)2]·2CH3CN (2), which does not include pivalate ligands, but contains one bridging sulfate anion and two bridging oxygen atoms. The X-ray study, cyclic voltammetry and magnetic measurements were performed allowing to conclude that both vanadium centers in 2 are in +5 oxidation state. According to ESR studies the dinuclear complex 1 undergoes dissociation upon dissolution in ethanol yielding mononuclear species VO(μ2-SO4)(dtb-bpy)(CH3OH), while solution of 1 in dichloromethane contains “dimers” exhibiting spin–spin exchange interactions between two paramagnetic monomeric fragments. [Copyright &y& Elsevier]

Abstract: Octacarbonyldicobalt reacts with tricyclic 5,8-di(tert-butyl)-2,3-dihydro-1,4-ethanoquinoxaline-6,7-dione and 5,8-di-tert-butyl-2,3-dihydrobenzo[b][1,4]dioxine-6,7-dione to give tris-o-semiquinonato complexes (1 and 2, respectively). X-ray structural study indicate exact trigonal prismatic environment of cobalt in 1 and slightly twisted one in 2. Rigid and flexible steric configurations of N,N′-piperazino- and O,O′-ethane-1,2-diolato-cyclic fragments of ligands are responsible for trigonal prismatic molecular geometry of 1 and twisted one for 2. Magnetic moment temperature dependences have very close shapes for 1 and 2 and correspond to S =1/2 ground state. High temperature limits exceed spin-only value calculated for three noninteracting spins on three semiquinones. Precision calorimetric study of temperature dependence of heat capacity of 1 does not detect significant anomalies. [Copyright &y& Elsevier]

Abstract: New polynuclear heteroligand complexes [(η-HPiv)2(μ2-Hmhp)4Na6Co5(μ6,η2-O3PPh)2(μ3,η2-Piv)2(μ3-Piv)3(μ-Piv)7]·2C10H22 (1·2C10H22) and [(η-H2O)4Na12Co12(μ5,η2-O3PPh)4(μ6-O3PPh)4(μ3,η2-mhp)8(μ2-Piv)4(μ3-Piv)8]·1.25C10H22 (2·1.25C10H22), where Hmhp is 6-methyl-2-pyridone, mhp is the 6-methyl-2-piridonate, and Piv is the pivalate anion, were obtained by the self-assembly of {Co(Piv)2} n , Na2O3PPh, and Hmhp in boiling decane (174°C). The structures of compounds 1·2C10H22 and 2·1.25C10H22 were determined by single-crystal X-ray diffraction. The magnetic properties of these compounds and their thermal decomposition were investigated. The removal of coordinated water molecules from complex 2·1.25C10H22 begins at 470°С. [Copyright &y& Elsevier]

Abstract: New dodecanuclear phenylphosphonate-bridged Co(II) complexes [(μ2-THF)5(η-HPiv)Co12(μ3-OH)4(μ6-O3PPh)4(μ-Piv)12]·THF·2С6Н6 (1·THF·2С6Н6), [(μ2-THF)6Co12(μ3-OH)4(μ6-O3PPh)4(μ-Piv)12]·3THF (2·3THF) and [(μ2-Hmhp)6Co12(μ3-OH)4(μ6-O3PPh)4(μ-Piv)12]·6.5MeCN (3·6.5MeCN) have been synthesized by the reaction of the cobalt(II) pivalate polymer {Co(Piv)2} n (Piv is the pivalate anion), as a source of metal fragments containing cobalt(II) atoms, with potassium phenylphosphonate (K2PO3Ph) in the presence of neutral O-donor additional ligands like molecules of THF or 6-methyl-2-pyridone (Hmhp). The structures of the dodecanuclear complexes 1–3 were determined by using single-crystal X-ray diffraction data. The magnetic properties of the compounds showed that complexes 1 and 3 exhibit antiferromagnetic exchange interactions between the magnetic centers. The stability of compounds 1 and 3 were studied using thermogravimetric analysis. [Copyright &y& Elsevier]

Abstract: Solid heterospin compounds based on Cu(hfac)2 complexes with a new group of nitronyl nitroxides bearing different azine-N-oxide substituents at position 2 of the 2-imidazoline ring (L n ) were studied. The major factor responsible for the change in the magnetic characteristics of the [Cu(hfac)2L1] complex with triazine nitronyl nitroxide with temperature was shown to be the specific pairwise packing of heterospin molecules with the dominant antiferromagnetic exchange between the radical fragments of adjacent molecules. For complexes of Cu(hfac)2 with 1-oxoazin-2-yl-substituted nitronyl nitroxides L2 and L4, 7-membered metallocycles were obtained, although they form rarely. It was shown that polymer chains formed in the solid complex with spin-labeled pyrazine-N-oxide [(Cu(hfac)2)3(L3)2] due to the cross-linking of {(Cu(hfac)2)2(L3)2} binuclear fragments via the bridging [Cu(hfac)2]. [Copyright &y& Elsevier]

It is shown that SNH approach opens new possibilities in the synthesis of polyfunctional nitronyl and imino nitroxides. It is found that the interaction of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl lithium salt Li1 with 3,6-diaryl-1,2,4-triazines leads to formation of the corresponding triazines bearing nitronyl nitroxide or imino nitroxide substituent at position 5 of the heterocycle. The reaction of Li1 with pyridazine-N-oxide gives rise to nitroxide with buten-3-ynyl substituent 5. Spin-labeled 5 could be readily transformed by the use of 1,3-dipolar and nucleophilic addition reactions, as well as oxidative coupling, that gives a large group of new paramagnets: 2-(1H-pyrazol-5-yl)vinyl-, 2-ethynylcyclopropyl-, 2-(3-(ethoxycarbonyl) isoxazol-5-yl)vinyl-, 1-(pyrrolidin-1-yl)but-3-ynyl-substituted nitronyl nitroxide and a diradical - 2,2'-((1E,7E)-octa-1,7-dien-3,5-diyne-1,8-diyl)bis(4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl). The new nitroxides were characterized by X-ray single crystal data, ESR and static magnetic susceptibility measurements. [ABSTRACT FROM AUTHOR]

Crystals of solid solutions of valence tautomeric (VT) cobalt complex with inert compounds of Zn, Ni and Mn detect VT transition independently on the composition. Temperature of VT transition depends on the nature of inert component. X-ray diffraction indicates superposition of structures of components of solid solutions. [Display omitted] Bis-o-semiquinonato cobalt complex (2,2′-bpy)Co(3,6-DBSQ) 2 (1) is known to be redox-isomeric (valence tautomeric), i. e. undergo reversible ligand–metal electron transfer accompanied with spin crossover of metal ion under external excitation (2,2′-bpy – 2,2′-bipyridine; 3,6-DBSQ – 3,6-di- tert -butyl- o -benzosemiquinone). The using of one pot reaction allowed us to obtain the number of solid solutions of cobalt complex 1 with similar complexes (2,2′-bpy)M(dioxolene) 2 of M = zinc (2), M = nickel (3) and M = manganese (4) in the ratios 1:1 and 1:5 (dioxolene = redox forms of 3,6-di- tert -butyl- o -benzosemiquinone). Composition of solid solutions was established by X-ray spectral microanalysis and confirmed by magnetic measurements. The metals ratio taken into reaction is well reproduced in solid solution. Crystal structures of solid solutions were established by single crystal X-ray diffraction study. X-ray diffraction pattern allows to observe the superpositions of two structures. Variable temperature magnetic susceptibility measurements show that magnetizations of solid solutions are additive and are composed of magnetizations of both complexes. Redox-isomeric transformation occurs in all solid solutions independently of their compositions. The dilution of redox-isomeric compound 1 by inert components 2 and 3 (with zinc and nickel complexes) results in diminishing of transition temperature whereas the dilution by manganese compound does not affect the transition temperature. The reason of this result is proposed to be the maximal difference in molecules volumes (which is determined by ionic radii and charge distributions between metal and ligands) in cobalt/zinc and cobalt/nickel pairs being compared to cobalt/manganese one. [ABSTRACT FROM AUTHOR]

Abstract: It was established that the reactions of pyrazol-3-yl-substituted nitronyl nitroxide (HL 1) and pyrazol-3-yl-substituted imino nitroxide (HL 3) with Cu(II) acetate lead to self-assembly of the Cu4(OH)2(OAc)4(DMF)2(L1)2 tetranuclear and Cu2(OAc)2(H2O)2(L3)2 dinuclear complexes, respectively. The reaction of Cu(II) acetate with 5-ethoxycarbonyl-pyrazol-3-yl-substituted nitronyl nitroxide (HL 2) gave unexpected solid Cu2(H2O)2(L6)2 ·2DMF, in which L 6 is a deprotonated 5-carboxy-pyrazol-3-yl-substituted nitronyl nitroxide, formed as a result of cleavage of an ester bond in the starting HL 2. A similar transformation of the paramagnetic ligand was observed in the reaction of Cu(II) acetate with 5-ethoxycarbonyl-pyrazol-3-yl-substituted imino nitroxide (HL 4). It led to the formation of Cu2(DMF)2(L7)2, where L 7 is deprotonated 2-(5-carboxy-1H-pyrazol-3-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide. An X-ray diffraction study indicated that in Cu4(OH)2(OAc)4(DMF)2(L1)2 and Cu2(OAc)2(H2O)2(L3)2, the L 1 and L 3 paramagnetic ligands perform the bridging cyclic tridentate function, while in Cu2(H2O)2(L6)2 ·2DMF and Cu2(DMF)2(L7)2, the paramagnetic L 6 and diamagnetic L 7 are bridging bicyclic tetradentate ligands. The magnetic behavior of complexes with coordinated nitronyl nitroxide – Cu4(OH)2(OAc)4(DMF)2(L1)2 and Cu2(H2O)2(L6)2 ·2DMF is dictated by the dominant antiferromagnetic exchange interactions, which is confirmed by quantum-chemical data. The magnetic susceptibility of Cu2(OAc)2(H2O)2(L3)2 reflects the competition between the antiferromagnetic and ferromagnetic components, of which the latter is due to electron coupling in the Cu(II)←N=C–N∸O exchange channels. EPR data confirm the results received from static magnetic measurements for multispin solids. [Copyright &y& Elsevier]

• A series of bis(2-phenethyl)dithiophosphinate Ln(III) complexes was synthesized. • The photoluminescence and magnetic properties of all complexes were investigated. • The lowest triplet energy level of bis(2-phenethyl)dithiophosphinate ion was determined. • The impact of chemical composition of the complexes on the luminescent properties was studied. A series of the bis(2-phenethyl)dithiophosphinate-based lanthanide(III) complexes, namely [Ln(phen)L 3 ] (Ln = Sm (1), Eu (2)), Ln(phen)L 2 (NO 3) (Ln = Sm (3), Eu (4), Tb (5)), and Et 4 N[LnL 4 ] (Ln = Sm (6), Eu (7), Gd (8), Tb (9)), where L− = (PhCH 2 CH 2) 2 PS 2 −, and phen = 1,10-phenanthroline, has been designed and synthesized. The magnetic properties of complexes 1 – 9 have been investigated in the temperature range of 2–300 K. The μ eff (T) and 1/ χ (T) dependences of complexes show paramagnetic behavior, which is determined by the Ln3+ ions. For complexes 5 and 9 , significant anisotropy results in nonlinear field dependencies of magnetization at 2 K. Complexes 1 – 7 and 9 exhibit metal-centered luminescence in the solid state at room temperature, whereas complex 8 emits ligand-centered phosphorescence. The maximal quantum efficiency (φ f = 53% at 300 K) is observed for the complex Tb(phen)L 2 (NO 3). [ABSTRACT FROM AUTHOR]

New stable polyfluorinated nitroxide radicals for use in cross-coupling reactions, namely, N-tert-butyl-N-oxyamino-2,3,5,6-tetrafluoro-4-iodobenzene and N-tert-butyl-N-oxyamino-2,3,5,6-tetrafluoro-4-ethynylbenzene, were prepared from perfluoroiodobenzene. The reaction of the polyfluoro derivative with tert-butylamine under autoclaving conditions leading to the formation of N-tert-butyl-2,3,5,6-tetrafluoro-4-iodoaniline proved to be the key stage of the whole process. The fluorinated tert-butyl iodophenyl nitroxide was found to form in a solid state via N–O···I halogen bonds, a one-dimensional assembly of the radicals. The acceptor role of the nitroxide group in the halogen bonding changes to a donor role when the nitroxide reacts with Cu(hfac)2. In the last case, zero-dimensional assembly prevails, giving a three-spin complex with axial coordinated nitroxide groups and, as a consequence, causing ferromagnetic intramolecular exchange interactions between Cu(II) and radical spins. [ABSTRACT FROM AUTHOR]

• Four novel bis(dioxolene) 3 d -transition metal complexes have been synthesized. • Nature of metal ion determines charge distribution of the complex. • Cobalt demonstrates redox-isomeric transformation at temperatures above 220 K. Here the synthesis, the molecular structure and the magnetic propertiesof four novel six-coordinated bis-dioxolene nickel and cobalt complexes with various di(pyridyl)imines as ancillary N-donor ligands is discussed. Despite the analogous composition the obtained compounds show different charge distribution dependently on the nature of complexing metal. Bis- o -semiquinonato nickel(II) complexes demonstrate the strong ferromagnetic exchange interaction between unpaired electrons of the high-spin nickel ion and anion-radical ligands. Cobalt complex containing naphtyl-substituted ancillary ligand demonstrates the proceeding of solid-state redox-isomeric transformation at temperatures above 220 K. [ABSTRACT FROM AUTHOR]

Novel coordination compounds of cobalt(II), nickel(II), and copper(II) with 1-(pyrid-2-yl)-1 H -tetrazole have been synthesized. The ligand can be coordinated both monodentally and in a bidentate-cyclic way. The studies on the µ eff (T) for the polynuclear copper(II) have shown antiferromagnetic exchange interactions between copper(II) ions to occur at a low temperature. • Novel complexes of 3d-metals with 1-(pyrid-2-yl)-1 H -tetrazole have been synthesized. • Ligand can be coordinated both monodentally and in a bidentate-cyclic way. • Polynuclear Cu(II) have shown exchange interactions between Cu(II) ions to occur. Coordination compounds of cobalt(II), nickel(II), and copper(II) with a poly nitrogen-containing heterocyclic ligand 1-(pyrid-2-yl)-1 H -tetrazole (1-Pytz) such as [Cu(1-Pytz) 2 Cl 2 ] n , [M(1-Pytz) 2 (H 2 O)Cl 2 ] (M = Co, Ni), [M(1-Pytz) 2 (C 2 N 3) 2 ] n (M = Co , Ni) have been synthesized. The compounds have been studied by means of infrared diffuse reflectance spectroscopy, single-crystal and powder X-ray diffraction, and static magnetic susceptibility. The studies on the µ eff (T) for the [Cu(1-Pytz) 2 Cl 2 ] n , [Co(1-Pytz) 2 (C 2 N 3) 2 ] n and [Ni(1-Pytz) 2 (C 2 N 3) 2 ] n polynuclear complexes in the temperature range of 2–300 K have shown that exchange interactions between spins of metal ions are weak. [ABSTRACT FROM AUTHOR]

Triazol-3-yl-1 H -tetrazole ligands show bridging coordination modes giving coordination polymers under action of copper(II) chloride. The peculiarity of complexation of 1-(1,2,4-triazol-3-yl)-1 H -tetrazole is the transformation of the tetrazole cycle under interaction with CuCl 2 /HCl leading to 3-amino-1,2,4-triazolium complex. 1-(1,2,4-Triazol-3-yl)-1 H -tetrazole (trt) and 1-(1- tert -butyl-1,2,4-triazol-3-yl)-1 H -tetrazole (btrt) were synthesized by heterocyclization of corresponding amines with triethyl orthoformate and sodium azide. The interaction of trt with copper(II) chloride in ethanol in the presence of hydrochloric acid was found to result in 1D coordination polymer [CuCl 2 (trt)(H 2 O)] n · n H 2 O. N - tert -butylated ligand btrt reacts with the copper salt in ethanol giving 2D coordination polymer [CuCl 2 (btrt)] n. Tetrazole ring-opening reaction with the formation of [CuCl 2 (3-amino-1,2,4-triazolium) 2 ][CuCl 4 ]·2H 2 O was observed in the interaction of trt with copper(II) chloride in aqueous hydrochloric acid. The temperature-dependent magnetic susceptibility measurements of [CuCl 2 (btrt)] n revealed that the copper(II) ions were weakly ferromagnetically coupled showing a coupling constant J of 1.2 cm−1. [ABSTRACT FROM AUTHOR]

A series of pyridyl-substituted nitronyl nitroxides was synthesized and structurally characterized. A comprehensive magnetochemical and quantum chemical study of extended raw of the nitroxides with different substituents R in the pyridine fragment was performed. It was shown, that temperature-dependent magnetic properties are determined by the short contacts between nitroxide groups of adjacent molecules as well as between nitroxide group and methyl substituents in the pseudo axial positions of imidazoline fragments. Quantum chemistry allows to select the appropriate model of exchange cluster for analysis of experimental magnetic data and evaluation of the exchange interaction parameters. For NN-Py Cl the "order-disorder" transition was detected by means of low temperature XRD. The difference in the experimental and calculated exchange interaction energies may serve as an indicator of temperature-induced structural rearrangements. For instance, for methyl substituted nitronyl nitroxide NN-Py Me structural transformations and significant changes in exchange interaction energies were observed., (© 2024 Wiley-VCH GmbH.)

Spontaneous solvent-controlled solid-state transformations were observed for a series of polymeric chain solvates [Cu(hfac) 2 L Pr ]·0.5Solv (Solv = (CH 3 ) 2 CO, THF, CH 2 Cl 2 , CH 2 Br 2 , CHCl 3 ) with 2-(1-propyl-1 H -imidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1 H -imidazole-3-oxide-1-oxyl (L Pr ) under ambient conditions. The conversion of powdered polymeric chain [Cu(hfac) 2 L Pr ]·0.5THF and [Cu(hfac) 2 L Pr ]·0.5(CH 3 ) 2 CO complexes, accompanied by the loss of solvent molecules, occurs completely to binuclear [Cu(hfac) 2 L Pr ] 2 within a day. On the other hand, in the case of [Cu(hfac) 2 L Pr ]·0.5Solv (Solv = CH 2 Cl 2 , CH 2 Br 2 , CHCl 3 ), the partial transformation into a desolvated 1D polymer [Cu(hfac) 2 L Pr ] or its mixture with [Cu(hfac) 2 L Pr ] 2 takes much longer time. The magnetic behavior of the isostructural solvates is highly sensitive to the included solvent molecules. The complexes with THF, CH 2 Cl 2 , CH 2 Br 2 , and CHCl 3 undergo a transition to a magnetically ordered state below 4 K, a phenomenon reported for the first time for the polymeric chain Cu(II) complexes with a "head-to-tail" motif. [Cu(hfac) 2 L Pr ]·0.5THF and [Cu(hfac) 2 L Pr ]·0.5(CH 3 ) 2 CO undergo a spin transition at 190 K, which is induced by the transformation of the Cu atom environment. In the case of the THF solvate, the increase in the distances between the Cu and oxygen atoms leads to enhanced ferromagnetic exchange interactions, while in the acetone solvate, the nitroxide coordination type changes from axial to equatorial at certain coordination sites, resulting in the emergence of strong antiferromagnetic exchange.

The title radical R⋅, synthesized by reduction of the corresponding cation R + , is thermally stable up to ~380 K in the crystalline state under anaerobic conditions. With SQUID magnetometry, single-crystal and powder XRD, solid-state EPR and TG-DSC, reversible spin-Peierls transition between diamagnetic and paramagnetic states featuring ~10 K hysteretic loop is observed for R⋅ in the temperature range ~310-325 K; ΔH=~2.03 kJ mol -1 and ΔS=~6.23 J mol -1 K -1 . The transition is accompanied by mechanical movement of the crystals, i. e., by thermosalient behavior. The low-temperature diamagnetic P-1 polymorph of R⋅ consists of R⋅ 2 π-dimers arranged in (…R⋅ 2 …) n π-stacks; whereas the high-temperature paramagnetic P2 1 /c polymorph, of uniform (…R⋅…) n π-stacks. With the XRD geometries, CASSCF and broken-symmetry DFT jointly suggest strong antiferromagnetic (AF) interactions within R⋅ 2 and weak between R⋅ 2 for the (…R⋅ 2 …) n stacks; and moderate AF interactions between R⋅ for the (…R⋅…) n stacks. The fully hydrocarbon archetype of R⋅ does not reveal the aforementioned properties. Thus, the fluorinated 1,3,2-benzodithiazolyls pave a new pathway in the design and synthesis of metal-less magnetically-bistable materials., (© 2024 Wiley-VCH GmbH.)

Valence tautomeric complexes (VT) are promising systems for creating molecular devices. From this viewpoint, valence tautomeric complexes with a hysteresis loop on the magnetic curve are of special interest as potential memory elements. The hysteresis loop is a consequence of retarded structural rearrangements which investigation is an actual problem. Recently, we have described a new VT transition taking place in a bis-dioxolene cobalt complex with imino-pyridine having a TEMPO substituent (A. A. Zolotukhin, et al. , Inorg. Chem. , 2017, 56 , 14751-14754). Valence tautomeric transformation occurs with a hysteresis loop and is accompanied by a phase transition. The phase transition taking place during cooling is accompanied by crystal destruction. This fact makes it impossible to monitor the structural changes responsible for the hysteresis loop. The current research attempts to resolve this problem. A nickel compound of the same composition (TEMPO-imino-pyridine)Ni(3,6-DBSQ) 2 was synthesized and characterized. It was established to be isostructural with the cobalt complex. It was used as an inert matrix for the dilution of the VT cobalt complex. The number of solid solutions with Co/Ni ratios of 1 : 1, 1 : 2, 1 : 4, and 1 : 8 was obtained. Variable temperature magnetic susceptibility measurements show that VT transformation with a hysteresis loop takes place in all solid solutions. The hysteresis loop is shifted to low temperatures primarily due to the shifting of its low-temperature boundary with dilution. The hysteresis width does not change significantly with dilution. DSC detected that transformations are accompanied by phase transitions at different temperatures at cooling and heating. The phase transition at the first cooling occurs at slightly lower temperatures compared with subsequent cycles. These temperatures correspond to the transition temperatures detected from the magnetic curves. The phase transition during the first cooling is accompanied by crystal destruction. Physical destruction takes place in the crystals of all solid solutions. X-ray diffraction powder patterns confirm that phase transition is accompanied by considerable reorganization of the crystal structure typical for the first order transitions. The unit cell volume of solid solutions is larger than that of pure complexes. Especially calculated crystal invariom indicated that the "lattice energy" in a solid solution is the lowest compared with that in "pure" nickel and cobalt complexes.

High-spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but examples reported to date exhibit limited stability and processability. In this work, we designed the first tetraradical based on an oxoverdazyl core and nitronyl nitroxide radicals and successfully synthesized it using a palladium-catalyzed cross-coupling reaction of an oxoverdazyl radical bearing three iodo-phenylene moieties with a gold(I) nitronyl nitroxide-2-ide complex in the presence of a recently developed efficient catalytic system. The molecular and crystal structures of the tetraradical were confirmed by single crystal X-ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼125 °C in an inert atmosphere; in a toluene solution upon prolonged heating at 90 °C in air, no decomposition was observed. The resulting unique verdazyl-nitroxide conjugate was thoroughly studied using a range of experimental and theoretical techniques, such as SQUID magnetometry of polycrystalline powders, EPR spectroscopy in various matrices, cyclic voltammetry, and high-level quantum chemical calculations. All collected data confirm the high thermal stability of the resulting tetraradical and quintet multiplicity of its ground state, which makes the synthesis of this important paramagnet a new milestone in the field of creating high-spin systems.

A novel synthetic approach has been employed to synthesize a series of new nitronyl nitroxides: 2-(1-propyl-1H-imidazol-5-yl)- (L n-Pr ), 2-(1-isopropyl-1H-imidazol-5-yl)- (L i-Pr ) and 2-(1-butyl-1H-imidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (L n-Bu ). The reaction of Cu(hfac) 2 with L R in a 1 : 2 ratio yields mononuclear heterospin complexes [Cu(hfac) 2 (L R ) 2 ] (L R =L n-Pr , L i-Pr , L n-Bu ), which have a similar crystal structure to the "jumping" crystals [Cu(hfac) 2 (L Me ) 2 ] that exhibit chemomechanical activity. It was shown that an increase in the alkyl substituent R leads to changes in the crystal packing of the molecules and the absence of chemomechanical activity. Furthermore, it was found that two polymorph modifications of the heterospin complex [Cu(hfac) 2 (L n-Pr ) 2 ] can be obtained, and magnetic properties of [Cu(hfac) 2 (L n-Pr ) 2 ] strongly depend on the angle between the planes of the paramagnetic fragment O•-N-C=N→O and the imidazole ring in L n-Pr ., (© 2023 Wiley-VCH GmbH.)

High-spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but those synthesized to date possess limited stability and processability. In this work, we have designed a tetraradical based on the Blatter's radical and nitronyl nitroxide radical moieties and successfully synthesized it by using the palladium-catalyzed cross-coupling reaction of a triiodo-derivative of the 1,2,4-benzotriazinyl radical with gold(I) nitronyl nitroxide-2-ide complex in the presence of a newly developed efficient catalytic system. The molecular and crystal structure of the tetraradical was confirmed by X-ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼150 °C under an inert atmosphere and exhibits reversible redox waves at -0.54 and 0.45 V versus Ag/AgCl. The magnetic properties of the tetraradical were characterized by SQUID magnetometry of polycrystalline powders and EPR spectroscopy in various matrices. The collected data, analyzed by using high-level quantum chemical calculations, confirmed that the tetraradical has a triplet ground state and a nearby excited quintet state. The unique high stability of the prepared triazinyl-nitronylnitroxide tetraradical is a new milestone in the field of creating high-spin systems., (© 2023 Wiley-VCH GmbH.)

This study explores the antiarrhythmic and hypotensive potential of pyridyl-substituted nitronyl nitroxides derivatives, uncovering the crucial role of a single carbon moiety of the pyridine cycle alongside radical and charged oxygen centers of the imidazoline fragment. Notably, the introduction of fluorine atoms diminished the antiarrhythmic effect, while the most potent derivatives featured the nitronyl nitroxide pattern positioned at the third site of the pyridine cycle. Gender-dependent responses were observed in lead compounds L CF 3 and L Me , with L Me inducing temporary bradycardia and hypotension specifically in female rats, and L CF3 causing significant blood pressure reduction followed by rebound in females compared to milder effects in males. Mechanistic insights point towards β 1 adrenoceptor blockade as an underlying mechanism, supported by experiments on isolated rat atria. This research underscores the interplay between structure, cardiovascular effects and gender-specific responses, offering insights for therapeutic strategies for treating free radical-associated cardiovascular disorders., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

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.

Copper(II)-nitroxide based Cu(hfac) 2 L R compounds exhibit unusual magnetic behavior that can be induced by various stimuli. In many aspects, the magnetic phenomena observed in Cu(hfac) 2 L R are similar to classical spin-crossover behavior. However, these phenomena originate from polynuclear exchange-coupled spin clusters Cu 2+ -O˙-N< or >N-˙O-Cu 2+ -O˙-N<. Such peculiarities may result in additional multifunctionality of Cu(hfac) 2 L R compounds, making them promising materials for spintronic applications. Herein, we investigate the Cu(hfac) 2 L MeMe material, which demonstrates a three-step temperature-induced magnetostructural transition between high-temperature, low-temperature, and intermediate states, as revealed by magnetometry. Two main steps were resolved using variable-temperature Fourier-transform infrared and Q-band electron paramagnetic resonance (EPR) spectroscopies. The intermediate-temperature states (∼40-90 K) are characterized by the coexistence of two types of copper(II)-nitroxide clusters, corresponding to the low-temperature and high-temperature phases. High-field EPR experiments revealed the effect of partial alignment of Cu(hfac) 2 L MeMe microcrystals in a strong (>20 T) magnetic field. This effect was used to unveil the structural features of the low-temperature phase of Cu(hfac) 2 L MeMe , which were inaccessible using single-crystal X-ray diffraction (XRD) technique. In particular, high-field EPR allowed us to determine the relative direction of the Jahn-Teller axes in CuO 6 and CuO 4 N 2 units.

A new bifunctional N 4 -ligand was obtained via the condensation reaction of acenaphthenequinone and 2-picolylamine. A peculiarity of this synthesis is the formation of a new intramolecular C-C bond during the reaction. The structure and redox properties of the ligand were studied. The anion-radical form of the ligand was prepared via the chemical reduction of the latter with metallic sodium as well as in situ via its electrochemical reduction in a solution. The sodium salt prepared was structurally characterized using single-crystal X-ray diffraction (XRD). New cobalt complexes with the ligand in neutral and anion-radical forms were synthesized and further studied. As a result, three new homo- and heteroleptic cobalt(II) complexes were obtained, in which the cobalt atom demonstrates different modes of coordination with the ligand. Cobalt(II) complex CoL 2 with two monoanionic ligands was prepared by the electrochemical reduction of a related L 2 CoBr 2 complex or by treating cobalt(II) bromide with the sodium salt. XRD was used to study the structures of all cobalt complexes prepared. Magnetic and electron paramagnetic resonance studies were performed: Co II ion states with S = 3/2 and S = 1/2 were found for the complexes. A quantum-chemical study confirmed that the spin density is mainly located at the cobalt center.

Functionalized perfluoroalkyl lithium β-diketonates (LiL) react with lanthanide(III) salts (Ln = Eu, Gd, Tb, Dy) in methanol to give heterobimetallic Ln-Li complexes of general formula [(LnL 3 )(LiL)(MeOH)]. The length of fluoroalkyl substituent in ligand was found to affect the crystal packing of complexes. Photoluminescent and magnetic properties of heterobimetallic β-diketonates in the solid state are reported. The effect of the geometry of the [LnO 8 ] coordination environment of heterometallic β-diketonates on the luminescent properties (quantum yields, phosphorescence lifetimes for Eu, Tb, Dy complexes) and single-ion magnet behavior ( U eff for Dy complexes) is revealed.

Fast crystallization of the monoclathrochelate cobalt(II) intracomplex [Co(Cl 2 Gm) 3 (BAd) 2 ] (where Cl 2 Gm 2- is a dichloroglyoxime dianion and BAd is an adamantylboron capping group, 1), initially obtained by the direct template condensation of the corresponding chelating α-dioximate and cross-linking ligand synthons on the Co 2+ ion as a matrix, from benzene or dichloromethane afforded its structural triclinic and hexagonal polymorphs. Its prolonged recrystallization from dichloromethane under air atmosphere and sunlight irradiation unexpectedly gave the crystals of the Co III Co II Co III -trinuclear dodecachloro-bis-clathrochelate intracomplex [[Co III (Cl 2 Gm) 3 (BAd)] 2 Co II ] (2), the molecule of which consists of two macrobicyclic frameworks with encapsulated low-spin (LS) Co 3+ ions, which are cross-linked by a μ 3 -bridging Co 2+ ion as a bifunctional Lewis-acidic center. The most plausible pathway of such a 1 → 2 transformation is based on the photoinitiated radical oxidation of dichloromethane with air oxygen giving the reactive species. Cobalt(II) monoclathrochelate 1 was found to undergo a temperature-induced spin crossover (SCO) both in its solutions and in the solid state. In spite of the conformational rigidity of the corresponding quasiaromatic diboron-capped tris-α-dioximate framework, the main parameters of this SCO transition ( i.e. , its completeness and gradual character) are strongly affected by the nature of the used solvent (in the case of its solutions) and by the structural polymorphism of its crystals (in the solid state). In the latter case, the LS state ( S = 1/2) of this complex is more thermally stable and, therefore, the cobalt(II)-centered 1/2 → 3/2 SCO is more gradual than that in solutions.

Magnetic topological insulators (MTIs) have recently become a subject of poignant interest; among them, Z 2 topological insulators with magnetic moment ordering caused by embedded magnetic atoms attract special attention. In such systems, the case of magnetic anisotropy perpendicular to the surface that holds a topologically nontrivial surface state is the most intriguing one. Such materials demonstrate the quantum anomalous Hall effect, which manifests itself as chiral edge conduction channels that can be manipulated by switching the polarization of magnetic domains. In the present paper, we uncover the atomic structure of the bulk and the surface of Mn 0.06 Sb 1.22 Bi 0.78 Te 3.06 in conjunction with its electronic and magnetic properties; this material is characterized by naturally formed ferromagnetic layers inside the insulating matrix, where the Fermi level is tuned to the bulk band gap. We found that in such mixed crystals septuple layers (SLs) of Mn(Bi,Sb) 2 Te 4 form structures that feature three SLs, each of which is separated by two or three (Bi,Sb) 2 Te 3 quintuple layers (QLs); such a structure possesses ferromagnetic properties. The surface obtained by cleavage includes terraces with different terminations. Manganese atoms preferentially occupy the central positions in the SLs and in a very small proportion can appear in the QLs, as indirectly indicated by a reshaped Dirac cone.

A series of new charge transfer (CT) chromophores of "α-diimine-M II -catecholate" type (where M is 3d-row transition metals-Cu, Ni, Co) were derived from 4,4'-di- tert -butyl-2,2'-bipyridyl and 3,6-di- tert -butyl- o -benzoquinone ( 3,6-DTBQ ) in accordance with three modified synthetic approaches, which provide high yields of products. A square-planar molecular structure is inherent for monomeric [Cu II (3,6-Cat)(bipy t Bu )]∙THF ( 1 ) and Ni II (3,6-Cat)(bipy t Bu ) ( 2 ) chromophores, while dimeric complex [Co II (3,6-Cat)(bipy t Bu )] 2 ∙toluene ( 3 ) units two substantially distorted heteroleptic D-M II -A (where D, M, A are donor, metal and acceptor, respectively) parts through a donation of oxygen atoms from catecholate dianions. Chromophores 1 - 3 undergo an effective photoinduced intramolecular charge transfer (λ = 500-715 nm, extinction coefficient up to 10 4 M -1 ·cm -1 ) with a concomitant generation of a less polar excited species, the energy of which is a finely sensitive towards solvent polarity, ensuring a pronounced negative solvatochromic effect. Special attention was paid to energetic characteristics for CT and interacting HOMO/LUMO orbitals that were explored by a synergy of UV-vis-NIR spectroscopy, cyclic voltammetry, and DFT study. The current work sheds light on the dependence of CT peculiarities on the nature of metal centers from various groups of the periodic law. Moreover, the "α-diimine-M II -catecholate" CT chromophores on the base of "late" transition elements with differences in d-level's electronic structure were compared for the first time.

Thermally resistant air-stable organic triradicals with a quartet ground state and a large energy gap between spin states are still unique compounds. In this work, we succeeded to design and prepare the first highly stable triradical, consisting of oxoverdazyl and nitronyl nitroxide radical fragments, with a quartet ground state. The triradical and its diradical precursor were synthesized via a palladium-catalyzed cross-coupling reaction of diiodoverdazyl with nitronyl nitroxide-2-ide gold(I) complex. Both paramagnetic compounds were fully characterized by single-crystal X-ray diffraction analysis, superconducting quantum interference device magnetometry, EPR spectroscopy in various matrices, and cyclic voltammetry. In the diradical, the verdazyl and nitronyl nitroxide centers demonstrated full reversibility of redox process, while for the triradical, the electrochemical reduction and oxidation proceed at practically the same redox potentials, but become quasi-reversible. A series of high-level CASSCF/NEVPT2 calculations was performed to predict inter- and intramolecular exchange interactions in crystals of di- and triradicals and to establish their magnetic motifs. Based on the predicted magnetic motifs, the temperature dependences of the magnetic susceptibility were analyzed, and the singlet-triplet (135 ± 10 cm -1 ) and doublet-quartet (17 ± 2 and 152 ± 19 cm -1 ) splitting was found to be moderate. Unique high stability of synthesized verdazyl-nitronylnitroxide triradical opens new perspectives for further functionalization and design of high-spin systems with four or more spins.

The reactions of monomeric [(dpp-Bian)M(thf) 4 ] (M = Ca ( 1a ), Sr ( 1b ); dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with 4,4'-bipyridyl (4,4'-bipy) proceed with electron transfer from dpp-Bian 2- to 4,4'-bipy 0 to afford calcium and strontium complexes containing simultaneously radical-anionic dpp-Bian - and 4,4'-bipy - ligands. In tetrahydrofuran (thf) the reactions result in 1D coordination polymers [{(dpp-Bian)M(4,4'-bipy)(thf) 2 }·4thf] n (M = Ca ( 2a ), Sr ( 2b )), while in a thf/benzene mixture the reaction between 1a and 4,4'-bipy affords the 2D metal-organic framework [{(dpp-Bian)Ca(4,4'-bipy) 2 }·2thf·2C 6 H 6 ] n ( 3 ). The structures of compounds 2a , b and 3 have been determined by single-crystal X-ray analyses. The presence of the ligand-localized unpaired electrons allows the use of ESR spectroscopy for characterization of the compounds 2a , b and 3 . DFT calculations of model calcium complexes with the dpp-Bian, 4,4'-bipy, and thf ligands confirm the energetically favorable open-shell configurations of the molecules bearing the 4,4'-bipy fragments. The magnetic susceptibility measurements confirm the presence of two unpaired electrons per monomeric unit in 2a , b and 3 . The thermal stability of compounds 2a , b and 3 was studied by thermogravimetric analysis (TGA). To the best of our knowledge, 3 is the first MOF simultaneously containing two different paramagnetic bridging ligands inside the framework.

Thermally stable organic diradicals with a triplet ground state along with large singlet-triplet energy gap have significant potential for advanced technological applications. A series of phenylene-bridged diradicals with oxoverdazyl and nitronyl nitroxide units were synthesized via a palladium-catalyzed cross-coupling reaction of iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields. The diradicals exhibit high stability and do not decompose in an inert atmosphere up to 180 °C. For the diradicals, both substantial AF (ΔE ST ≈-64 cm -1 ) and FM (ΔE ST ≥25 and 100 cm -1 ) intramolecular exchange interactions were observed. The sign of the exchange interaction is determined both by the bridging moiety (para- or meta-phenylene) and by the type of oxoverdazyl block (C-linked or N-linked). Upon crystallization, diradicals with the triplet ground state form unique one-dimensional exchange-coupled chains with strong intra- and weak inter-diradical ferromagnetic coupling., (© 2020 Wiley-VCH GmbH.)

Five trans-1,4-cyclohexanedicarboxylate (chdc 2- ) metal-organic frameworks of transition metals were synthesized in aqueous systems. A careful control of pH, reaction temperature and solvent composition were shown to direct the crystallization of a particular compound. Isostructural [Co(H 2 O) 4 (chdc)] n ( 1 ) and [Fe(H 2 O) 4 (chdc)] n ( 2 ) consist of one-dimensional hydrogen-bonded chains. Compounds [Cd(H 2 O)(chdc)] n ∙0.5nCH 3 CN ( 3 ), [Mn 4 (H 2 O) 3 (chdc) 4 ] n ( 4 ) and [Mn 2 (Hchdc) 2 (chdc)] n ( 5 ) possess three-dimensional framework structures. The compounds 1 , 4 and 5 were further characterized by magnetochemical analysis, which reveals paramagnetic nature of these compounds. A presence of antiferromagnetic exchange at low temperatures is observed for 5 while the antiferromagnetic coupling in 4 is rather strong, even at ambient conditions. The thermal decompositions of 1 , 4 and 5 were investigated and the obtained metal oxide (cubic Co 3 O 4 and MnO) samples were analyzed by X-ray diffraction and scanning electron microscopy., Competing Interests: The authors declare no conflict of interest.

The tetracoordinated square-planar CoIII complex (imSQC(O)Ph)CoIII(APC(O)Ph) (1) bearing a radical anion and the closed-shell o-amidophenolate forms of the functionalized o-aminophenol H2LC(O)Ph were synthesized. The intermediate spin state (SCo = 1) CoIII center was found for compound 1. The cyclic voltammogram of derivative 1 contains two oxidative processes and one reductive redox process as well as an additional multi-electron wave at high negative potentials above -2 V, which can involve both the ligand and metal center. One-electron oxidation of 1 by silver triflate produces the [(imSQC(O)Ph)CoII(imQC(O)Ph)]OTf·2toluene (2) derivative with the trigonal prismatic coordination environment of the metal arising from the additional coordination of -C(O)Ph hemilabile groups. This is a first example of a trigonal prismatic coordination polyhedron in cobalt-based complexes featuring o-iminobenzoquinone ligands. The trigonal prismatic geometry achieved by the unique flexibility of the ligand allows metal-to-ligand redox-induced electron transfer (RIET). Chemical oxidation of complex 1 promotes the reduction of CoIII to CoII in compound 2 due to the redox-active nature of o-iminobenzoquinonate ligands. Remarkably, this is the first example of RIET in cobalt-based derivatives with this type of ligand. The oxidative states of the ligands and cobalt ion in both complexes were unequivocally established according to the X-ray data collection by using the utility of "metric oxidation state" (MOS). The spin states of the metal centers were unambiguously determined by density functional theory. The strong antiferromagnetic exchange via metal-ligand interactions is dominant in compounds 1 and 2, giving the doublet (S = 1/2) and triplet (S = 1) ground spin state, respectively.

2-(3,5-Di- tert -butyl-4-hydroxyphenyl)-5-(4-iodophenyl)-4,4-dimethyl-4 H -imidazole 3-oxide reacts with phenylboronic acid and its substituted derivatives in a cross-coupling reaction of the Suzuki-Miyaura type to form 5-biphenyl derivatives of 4 H -imidazole- N -oxide. Interaction of the same compound with B 2 (pin) 2 in the presence of PdCl 2 (PPh 3 ) 2 proceeds through the formation of intermediate 1,3,2-dioxoborolane and leads to the product of homocoupling: biphenyl-bis(imidazole). Oxidation of the resultant imidazoles with lead dioxide quantitatively yields stable conjugated phenoxyl-nitroxyl mono- and diradicals, which are of interest as electroactive paramagnetic materials. The crystal structure of the monoradical, 2,6-di- tert -butyl-4-[1-oxido-4-(biphenyl-4-yl)-5,5-dimethyl-1 H -imidazole-2(5 H )-ylidene]cyclohex-2,5-dienone, its magnetic susceptibility, EPR spectra of the obtained hybrid radicals in solution, and cyclic voltammetry characteristics of 4 H -imidazoles were studied., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

An unexpected substitution of the anionic chelating ligands at the M II centre by a neutral tripodal ligand has been observed in the reaction of Mn II , Co II , Ni II and Cu II hexafluoroacetylacetonates (hfac) with tris(2-pyridyl)phosphine (Py 3 P) or its oxide (Py 3 P = O). The nature of the metal ion in M(hfac) 2 and the M/L ratio determine the degree of substitution of hfac-anions (partial vs. total) and therefore, the structure of the complex formed (scorpionate vs. bis-scorpionate ones, respectively). Hence, the reaction of the ligands with [Cu(hfac) 2 (H 2 O) 2 ] in an equimolar ratio affords scorpionate [Cu(N,N',N''-Py 3 P = X)(O,O'-hfac)(O-hfac)], wherein one hfac-ligand chelates metal, while the other hfac acts as an O-monodentate one. Using the two equivalents of Py 3 P in this reaction leads to [Cu(N,N',N''-Py 3 P) 2 ](hfac) 2 , which contains a bis-scorpionate cation [Cu(Py 3 P) 2 ] 2+ and two noncoordinated hfac-anions. [Co(hfac) 2 (H 2 O) 2 ] and [Ni(hfac) 2 (H 2 O) 2 ], regardless of the M/L molar ratio, react with Py 3 P = O to give cationic scorpionates [M(N,N',N''-Py 3 P = O)(O,O'-hfac)(H 2 O)](hfac), in which one hfac-anion is noncoordinated. In contrast, [Mn(hfac) 2 (H 2 O) 2 ], on interaction with Py 3 P, results in the cationic complex [Mn(N,N',N''-Py 3 P) 2 ][Mn(hfac) 3 ] 2 bearing a bis-scorpionate cation [Mn(Py 3 P) 2 ] 2+ and two [Mn(hfac) 3 ] 2 - counterions. The synthesized scorpionates have been characterized by X-ray diffractometry, cyclic voltammetry, SQUID magnetometry, FT-IR and UV-Vis techniques.

Low-temperature interaction of [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazole (1) with MoMes2 (Mes = mesitylene/1,3,5-trimethylbenzene) in tetrahydrofuran gave the heterospin (S1 = S2 = (1)/2) radical-ion salt [MoMes2](+)[1](-) (2) whose structure was confirmed by single-crystal X-ray diffraction (XRD). The structure revealed alternating layers of the cations and anions with the Mes ligands perpendicular, and the anions tilted by 45°, to the layer plane. At 300 K the effective magnetic moment of 2 is equal to 2.40 μB (theoretically expected 2.45 μB) and monotonically decreases with lowering of the temperature. In the temperature range 2-300 K, the molar magnetic susceptibility of 2 is well-described by the Curie-Weiss law with parameters C and θ equal to 0.78 cm(3) K mol(-1) and -31.2 K, respectively. Overall, the magnetic behavior of 2 is similar to that of [CrTol2](+)[1](-) and [CrCp*2](+)[1](-), i.e., changing the cation [MAr2](+) 3d atom M = Cr (Z = 24) with weak spin-orbit coupling (SOC) to a 4d atom M = Mo (Z = 42) with stronger SOC does not affect macroscopic magnetic properties of the salts. For the XRD structure of salt 2, parameters of the Heisenberg spin-Hamiltonian were calculated using the broken-symmetry DFT and CASSCF approaches, and the complex 3D magnetic structure with both the ferromagnetic (FM) and antiferromagnetic (AF) exchange interactions was revealed with the latter as dominating. Salt 2 is thermally unstable and slowly loses the Mes ligands upon storage at ambient temperature. Under the same reaction conditions, interaction of 1 with MoTol2 (Tol = toluene) proceeded with partial loss of the Tol ligands to afford diamagnetic product.

Bis(toluene)chromium(0), Cr(0)(η(6)-C7H8)2 (3), readily reduced [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazole (1) and [1,2,5]thiadiazolo[3,4-b]pyrazine (2) in a tetrahydrofuran solvent with the formation of heterospin, S1 = S2 = ½, radical-ion salts [3](+)[1](-) (4) and [3](+)[2](-) (5) isolated in high yields. The salts 4 and 5 were characterized by single-crystal X-ray diffraction (XRD), solution and solid-state electron paramagnetic resonance, and magnetic susceptibility measurements in the temperature range 2-300 K. Despite the formal similarity of the salts, their crystal structures were very different and, in contrast to 4, in 5 anions were disordered. For the XRD structures of the salts, parameters of the Heisenberg spin Hamiltonian were calculated using the CASSCF/NEVPT2 and broken-symmetry density functional theory approaches, and the complex magnetic motifs featuring the dominance of antiferromagnetic (AF) interactions were revealed. The experimental χT temperature dependences of the salts were simulated using the Van Vleck formula and a diagonalization of the matrix of the Heisenberg spin Hamiltonian for the clusters of 12 paramagnetic species with periodic boundary conditions. According to the calculations and χT temperature dependence simulation, a simplified magnetic model can be suggested for the salt 4 with AF interactions between the anions ([1](-)···[1](-), J1 = -5.77 cm(-1)) and anions and cations ([1](-)···[3](+), J2 = -0.84 cm(-1)). The magnetic structure of the salt 5 is much more complex and can be characterized by AF interactions between the anions, [2](-)···[2](-), and by both AF and ferromagnetic (FM) interactions between the anions and cations, [2](-)···[3](+). The contribution from FM interactions to the magnetic properties of the salt 5 is in qualitative agreement with the positive value of the Weiss constant Θ (0.4 K), whereas for salt 4, the constant is negative (-7.1 K).