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As a result of the electrochemical oxidation process, the [FeIII(5Cl‐thsa)2]− spin‐crossover (SCO) anion with N2S2O2 coordination sphere transforms into N4O2‐coordinated FeIII SCO neutral binuclear complex 2 with twist of two disulfide bridges. Each dimeric complex is a binuclear double‐stranded helicate with similar chirality of both Fe centers. The crystal structure of the complex 2 ⋅ 3H2O at 100 K has a monoclinic C2/c space group and contains large cavities (about 21.5 % of the unit cell volume) half‐filled by 3 water molecules per one dimer. The N4O2 coordination of iron(III) with two oxygen atoms (−O−) of phenoxy groups, two imine‐type (−Nim=) nitrogen atoms of azomethine groups, one amidrazone‐type (=NamidH) nitrogen atom and one ionized terminal group (−NionizH) of nitrogen has not been observed in CCDC so far. The oxidation state of the iron atoms in the dimeric complex was confirmed by 57Fe Mössbauer spectroscopy on 90 % enriched 57Fe sample. Mössbauer spectra and dc magnetic measurements demonstrated the partial HS‐HS→LS‐LS SCO in the 185–225 K temperature range. The details of the structure of complex 2 and the features of its magnetic properties were refined by theoretical analysis based on DFT calculations. The B3LYP* functional correctly predicting the energy of the spin‐crossover process was revealed. [ABSTRACT FROM AUTHOR]

We report crystal growth and characterization of 4 new ternary layered bismuthides with compositions KZn2Bi2 (I), RbZn2Bi2 (II), RbCd2Bi2 (III), and CsCd2Bi2 (IV) that belong to the vast 122 family of compounds. Single crystals were grown by self‐flux technique and characterized by a combination of powder X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and single crystal X‐ray diffraction. All new compounds crystallize in the layered ThCr2Si2 structure type and exhibit the plate‐like morphology with weak bonding between layers. A significant structural difference between ACd2Bi2 and AZn2Bi2 is found and discussed. [ABSTRACT FROM AUTHOR]

The iron(III) anionic complex based on a pyruvic acid thiosemicarbazone ligand with the lithium cation Li[FeIII(thpy)2]·3H2O (1) has been synthesized and characterized by FTIR spectroscopy, powder and single crystal X-ray diffraction, direct current magnetic susceptibility measurements, and 57Fe Mössbauer spectroscopy. Moreover, the molecular structure of the [Fe(thpy)2]− anion has been determined for the first time. The [Fe(thpy)2]− units in the triclinic P1¯ lattice of 1 are assembled into layers parallel to the bc plane. The Li+ cations and water molecules are located between the layers and the structure is stabilized by hydrogen bonding. The [Fe(thpy)2]− anions form interconnected dimer pairs through hydrogen bonds and short contacts with Fe⋯Fe separation of 6.7861(4) Å. According to dc magnetic measurements, compound 1 demonstrates an incipient spin-crossover transition from the LS (S = 1/2) to the HS (S = 5/2) state above 250 K. The Bleaney–Bowers equation for a model of an isolated LS dimer with a mean-field correction was applied to fit the experimental data of magnetic susceptibility dependence on temperature in the temperature range of 2–250 K. The intra-dimer J1 = −1.79(1) K and inter-dimer J2 = −0.24(3) K antiferromagnetic coupling constants were defined. The analysis of the 57Fe Mössbauer spectra at 80 K and 296 K confirms the presence of the shortened distances between the iron nuclei. Moreover, the influence of the lithium cation on the stabilization of the LS state was shown for the [Fe(thpy)2]− anion. BS-DFT calculations for the optimized structure of two isolated [Fe(thpy)2]− anions also correctly predict a weak exchange J1(calc) = −0.92 K. DFT calculations revealed the OPBE (GGA-type) functional that correctly predicts the spin-crossover transition for the iron(III) thpy compounds. Besides, the effect of the N2O4, N2S2O2, and N2Se2O2 coordination environments on the energy stabilization of the LS state of iron(III) anionic thpy complexes was noted as well. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of a first salt‐inclusion aluminophosphate oxocuprate, (Na,Li)3(Cl,OH)[Cu3OAl(PO4)3], obtained as single crystals, is reported. A novel phase, with a strongly pseudo‐orthorhombic structure, is described as a monoclinic crystal structure established by the study of a pseudomerohedric microtwin. It was investigated using scanning electron microscopy, microprobe analysis and low‐temperature X‐ray diffraction. The composite crystal structure represents an original framework assembled from Cu‐centered polyhedra, AlO6 octahedra and PO4 tetrahedra with channels, which incorporate the Na/Li salt component [(Na,Li)3(Cl,OH)]2+ that ensures electroneutrality of the compound. Layers of strongly corrugated chains of Cu‐centered octahedra with shared edges and linked by PO4 tetrahedra are shown to be topologically identical with the layers also built from Cu‐centered polyhedra and AsO4/VO4 tetrahedra forming the crystal structure of a fumarolic mineral aleutite, (M0.5Cl)[Cu5O2(AsO4)(VO4)] [Siidra et al. (2019). MinMag, 83, 847–853]. 'Sawtooth chains' and pairs of Cu‐centered octahedra inherent in the title structure may be of interest in solid‐state physics, engaging studies in the field of low‐dimensional and frustrated magnetism. [ABSTRACT FROM AUTHOR]

Four new heterometallic complexes combining [MII(H2dapsc)]2+ cations with the chelating H2dapsc {2,6-diacetylpyridine-bis(semicarbazone)} Schiff base ligand and [Cr(CN)6]3− anion were synthesized: {[MII(H2dapsc)]CrIII(CN)6K(H2O)2.5(EtOH)0.5}n·1.2n(H2O), M = Mn (1) and Co (2), {[Mn(H2dapsc)]2Cr(CN)6(H2O)2}Cl·H2O (3) and {[Co(H2dapsc)]2Cr(CN)6(H2O)2}Cl·2EtOH·3H2O (4). In all the compounds, M(II) centers are seven-coordinated by N3O2 atoms of H2dapsc in the equatorial plane and N or O atoms of two apical –CN/water ligands. Crystals 1 and 2 are isostructural and contain infinite negatively charged chains of alternating [MII(H2dapsc)]2+ and [CrIII(CN)6]3− units linked by CN-bridges. Compounds 3 and 4 consist of centrosymmetric positively charged trimers in which two [MII(H2dapsc)]2+ cations are bound through one [CrIII(CN)6]3− anion. All structures are regulated by π-stacking of coplanar H2dapsc moieties as well as by an extensive net of hydrogen bonding. Adjacent chains in 1 and 2 interact also by coordination bonds via a pair of K+ ions. The compounds containing MnII (1, 3) and CoII (2, 4) show a significant difference in magnetic properties. The ac magnetic measurements revealed that complexes 1 and 3 behave as a spin glass and a field-induced single-molecule magnet, respectively, while 2 and 4 do not exhibit slow magnetic relaxation in zero and non-zero dc fields. The relationship between magnetic properties and non-covalent interactions in the structures 1–4 was traced. [ABSTRACT FROM AUTHOR]

Three tetraphenylborates of mononuclear Mn(III) cation complexes with hexadentate ligands, the products of the reaction between a N,N′‐bis(3‐aminopropyl)ethylenediamine and salicylaldehydes with the different haloid substitutions at the 5 or 3,5 positions, have been synthesized: [Mn(5‐F‐sal‐N‐1,5,8,12)]BPh4 (1), [Mn(3,5‐diCl‐sal‐N‐1,5,8,12)]BPh4 (2) and [Mn(3,5‐Br,Cl‐sal‐N‐1,5,8,12)]BPh4 (3). Their crystal structure, dielectric constant (ϵ) and magnetic properties have been studied. Ligand substituents have a dramatic effect on the structure and magnetic properties of the complexes. With decreasing temperature, the complex (1) shows a gradual spin crossover from the high‐spin state (HS) to the HS:LS intermediate phase, followed by an abrupt transition to the low‐spin state (LS) without changing the crystal symmetry. The complexes 2 and 3 are isostructural, but have fundamentally different properties. Complex 2 demonstrates two structural phase transitions related to sharp spin crossovers from the HS to the HS:LS intermediate phase at 137 K and from the intermediate phase to the LS at 87 K, while complex 3 exhibits only one spin transition from the HS to the HS:LS intermediate phase at 83 K. [ABSTRACT FROM AUTHOR]

Heptacoordinated metal complexes with a pentadentate ligand 2,6-diacetylpyridine-bis(thiosemicarbazone) (H2daptsc) were used for the first time ever as building blocks to create polynuclear multifunctional molecular materials. Reactions of the paramagnetic [Mn(II)(H2daptsc)(H2O)2](ClO4)2 and [Mn(II)(H2daptsc)Cl2] complexes with photochromic sodium nitroprusside Na2[Fe(II)(CN)5NO].2H2O were studied. As a result, six polynuclear phases were obtained: {Mn(H2daptsc)Fe(CN)5NO}n·0.5n(MeOH)·0.5n(H2O) (1), {Mn(H2daptsc)Fe(CN)5NO}3n·8n(MeOH) (2), {Mn(H2daptsc)Fe(CN)5NO}2n·n(MeOH)·n(H2O) (3), [Mn(H2daptsc)Cl]2[Fe(CN)5NO] (4), {Mn(H2daptsc)Fe(CN)5NO}n·2n(H2O) (5) and {Mn(H2daptsc)Fe(CN)5NO}n·n(EtOH) (6). The crystal structures of the phases as well as the magnetic and photochromic properties of 1 and 4 were studied. [ABSTRACT FROM AUTHOR]

Single crystals of dinickel diphosphate dihydrate, Ni2(H2O)2[P2O7], have been synthesized by a hydrothermal method. Its structure was refined in the monoclinic P21/n space group (unit cell parameters a = 6.2517(1) Å, b = 13.7892(3) Å, c = 7.2894(2) Å, β = 94.507(2)°, V = 626.45(2) Å3, and Z = 4) based on low-temperature X-ray diffraction data until R – 0.016. Corrugated chains of NiO5(H2O) octahedra sharing edges are aligned in the [101¯] direction. They are linked into a three-dimensional framework through diphosphate groups and hydrogen bonds. A detailed crystal chemical analysis of the family Me2(H2O)2[X2O7] revealed correlations between the unit-cell parameters of the isotypic transition metal phosphates and arsenates, their structural features and the sizes of structure forming cations. Despite the isolation of the cis and trans edge-sharing infinite zigzag chains of Ni-centered octahedra from each other no pronounced low dimensionality is seen in the magnetic response of Ni2(H2O)2[P2O7]. The magnetic susceptibility χ evidences a short range correlation maximum at Tmax = 11.9 K accompanied by the onset of long-range magnetic order at TN = 9.4 K. Below TN, the title compound exhibits the features of an archetype three-dimensional easy-axis antiferromagnet which experiences a sequence of spin–flop and spin–flip phase transitions. Basing on specific heat Cp and magnetization M studies, the magnetic phase diagram of Ni2(H2O)2[P2O7] has been established. [ABSTRACT FROM AUTHOR]

A series of three mononuclear pentagonal-bipyramidal V(III) complexes with the equatorial pentadentate N3O2 ligand (2,6-diacethylpyridinebis(benzoylhydrazone), H2DAPBH) in the different charge states (H2DAPBH0, HDAPBH1−, DAPBH2−) and various apical ligands (Cl−, CH3OH, SCN−) were synthesized and characterized structurally and magnetically: [V(H2DAPBH)Cl2]Cl·C2H5OH (1), [V(HDAPBH)(NCS)2]·0.5CH3CN·0.5CH3OH (2) and [V(DAPBH)(CH3OH)2]Cl·CH3OH (3). All three complexes reveal paramagnetic behavior, resulting from isolated S = 1 spins with positive zero-field splitting energy expected for the high-spin ground state of the V3+ (3d2) ion in a PBP coordination. Detailed high-field EPR measurements for compound 3 show that its magnetic properties are best described by using the spin Hamiltonian with the positive ZFS energy (D = +4.1 cm−1) and pronounced dimer-like antiferromagnetic spin coupling (J = −1.1 cm−1). Theoretical analysis based on superexchange calculations reveals that the long-range spin coupling between distant V3+ ions (8.65 Å) is mediated through π-stacking contacts between the planar DAPBH2− ligands of two neighboring [V(DAPBH)(CH3OH)2]+ complexes. [ABSTRACT FROM AUTHOR]

Two novel K/Mn phosphate hydrates, namely, dipotassium trimanganese dipyrophosphate dihydrate, K2Mn3(H2O)2[P2O7]2, (I), and potassium manganese dialuminium triphosphate dihydrate, KMn(H2O)2[Al2(PO4)3], (II), were obtained in the form of single crystals during a single hydrothermal synthesis experiment. Their crystal structures were studied by X‐ray diffraction. Both new compounds are members of the morphotropic series of phosphates with the following formulae: A2M3(H2O)2[P2O7]2, where A = K, NH4, Rb or Na and M = Mn, Fe, Co or Ni, and AM2+(H2O)2[M3+2(PO4)3], where A = Cs, Rb, K, NH4 or (H3O); M2+ = Mn, Fe, Co or Ni; and M3+ = Al, Ga or Fe. A detailed crystal chemical analysis revealed correlations between the unit‐cell parameters of the members of the series, their structural features and the sizes of the cations. It has been shown that a mixed type anionic framework is formed in (II) by aluminophosphate [(AlO2)2(PO4)2]∞ layers, with a cationic topology similar to the Si/Al‐topology of the crystal structures of feldspars. A study of the magnetic susceptibility of (II) demonstrates a paramagnetic behaviour of the compound. [ABSTRACT FROM AUTHOR]

Reactions of [Mn(H2dapsc)Cl2]⋅H2O (dapsc=2,6‐ diacetylpyridine bis(semicarbazone)) with K3[Fe(CN)6] and (PPh4)3[Fe(CN)6] lead to the formation of the chain polymeric complex {[Mn(H2dapsc)][Fe(CN)6][K(H2O)3.5]}n⋅1.5n H2O (1) and the discrete pentanuclear complex {[Mn(H2dapsc)]3[Fe(CN)6]2(H2O)2}⋅4 CH3OH⋅3.4 H2O (2), respectively. In the crystal structure of 1 the high‐spin [MnII(H2dapsc)]2+ cations and low‐spin hexacyanoferrate(III) anions are assembled into alternating heterometallic cyano‐bridged chains. The K+ ions are located between the chains and are coordinated by oxygen atoms of the H2dapsc ligand and water molecules. The magnetic structure of 1 is built from ferrimagnetic chains, which are antiferromagnetically coupled. The complex exhibits metamagnetism and frequency‐dependent ac magnetic susceptibility, indicating single‐chain magnetic behavior with a Mydosh‐parameter φ=0.12 and an effective energy barrier (Ueff/kB) of 36.0 K with τ0=2.34×10−11 s for the spin relaxation. Detailed theoretical analysis showed highly anisotropic intra‐chain spin coupling between [FeIII(CN)6]3− and [MnII(H2dapsc)]2+ units resulting from orbital degeneracy and unquenched orbital momentum of [FeIII(CN)6]3− complexes. The origin of the metamagnetic transition is discussed in terms of strong magnetic anisotropy and weak AF interchain spin coupling. [ABSTRACT FROM AUTHOR]

The DFT calculations of the spin crossover complex [FeIII(Sal2-trien)]+ (1) with the following classification of conformers of 1 were performed. The study shows that rearrangements of ethylene group orientation in a coordinated ligand lead to the stabilization of the high-spin or low-spin iron(iii) state. [ABSTRACT FROM AUTHOR]

Isostructural mononuclear complexes of heavy lanthanides with the pentadentate Schiff-base dapsc ligand were synthesized, [Ln(H2dapsc)(H2O)4](NO3)3 (Ln = Tb, Dy, Ho, Er), and characterized structurally and magnetically. AC magnetic susceptibility measurements revealed that complexes of Dy3+ and Er3+ Kramers ions are field-induced single-ion magnets whereas the Tb and Ho complexes show no slow magnetic relation in DC fields up to 6000 Oe. DC and AC magnetic properties of these complexes were rationalized in terms of superposition crystal-field model calculations for Ln3+ ions, which have resulted in good agreement between the experiment and the theory. It is shown that low single-molecule magnet characteristics of the Dy and Er complexes and the absence of slow-magnetic relaxation in the Tb and Ho complexes are primarily due to the low-symmetry coordination of Ln3+ ions. [ABSTRACT FROM AUTHOR]

New crystals (1-4) of organic conductors based on the radical cation salts of the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with paramagnetic and diamagnetic tris(oxalato)metallate anions {A+[M3+(ox)3]3-G}2-, where M is Cr, Ga; G is 2-chloropyridine, 2-bromopyridine; and A+ is [K0.8(H3O)0.2]+ have been prepared and their crystal structure and transport properties were studied. All crystals belong to the monoclinic group of the (BEDT-TTF)4A+[M3+(ox)3]G family with α"-packing type of conducting BEDT-TTF layers. In contrast to the known superconducting crystals with M3+ = Fe3+ and G = 2-chloro- or 2-bromopyridine (Tc = 4.0-4.3 K), crystals with Cr3+ and Ga3+ ions exhibit metallic properties down to 0.5 K without superconducting transition. Upon cooling these crystals, the incommensurate superstructure appears, which has never been observed before in the numerous β"-salts of the family. In addition, orthorhombic (sp. group Pbca) semiconducting crystals α"-(BEDT-TTF)5[Ga(ox)3]·3.4·H2O·0.6 EtOH (5) were obtained. It is a new compound in the family of BEDT-TTF crystals with tris(oxalato)metallate anions. [ABSTRACT FROM AUTHOR]

The crystals of a perylene complex with the polymeric cluster containing [Mn6O2(O2CCHCl2)10(H2O)2] units assembled by 3,10-perylenequinone bridges, {[Mn6O2(O2CCHCl2)10(H2O)2(C20H10O2)]2n·(C20H12)n} (I), were obtained in the reaction of [Mn12O12(O2CCHCl2)16(H2O)4] with perylene. Unlike the Mn12 oxodichloroacetate cluster, the reaction of the Mn12 oxobenzoate cluster, [Mn12O12(O2CPh)16(H2O)4], with perylene does not occur. However, it turned out that the crystals isolated from the reaction are a new Mn12 oxobenzoate cluster containing three molecules of coordinated H2O and solvate molecules of hexane, [Mn12O12(O2CC6H5)16(H2O)3]·2C6H12 (II). Crystal structures of complexes I and II as well as the magnetic properties of the former were studied. [ABSTRACT FROM AUTHOR]