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The symmetry of one of the simplest hexamonodentate complexes, [M(H 2 O) 6 ] 2+ (M = Fe, Co, Ni, and Zn), was controlled by tuning interactions in the second coordination sphere. Highly symmetric Ti-Mo or Zr-Mo cluster cations acted as symmetry templates, imposing a crystallographic trigonal coordination geometry in the hexamonodentate complexes through intermolecular hydrogen-bonding interactions. Magnetic measurements revealed that the ideal trigonal symmetry results in weak spin-orbit coupling for high-spin Fe II complexes, despite the T-term ground state in the octahedral geometry. In contrast, high-spin Co II analogues with the T-term ground state exhibited strong spin-orbit coupling. DFT studies supported that a d 6 Fe II ion in the D 3 symmetry has a 5 A 1 ground state while a d 7 Co II in the same symmetry has a 4 E ground state. Single-ion magnet behavior was observed in the Co II complexes. These results demonstrate that incorporating a diamagnetic, highly symmetric cluster enables precise symmetry control in single-ion magnets containing only monodentate ligands.

Breast cancer has become one of the top five commonest causes of cancer death. The use of ferroptosis to induce the generation of reactive oxygen species (ROS) in cancer cells presents a promising and potential strategy for cancer treatment. Herein, a series of facile bimetallic nanoparticles ( x % Fe-doped ZIF-8) were synthesized and tested, and doxorubicin (DOX), a classic drug for breast cancer therapy, was encapsulated. After comparing the ratios of Fe 2+ /(Fe 2+ + Zn 2+ ), 7% Fe-doped ZIF-8 (7FZ) was found to be the most suitable particle for medical application. The drug loading efficiency of DOX@7FZ was 58.01 ± 0.02%. The pH-sensitive DOX@7FZ was degraded and DOX was released in lysosomes once internalized. Both the intracellular content of iron and ROS increased significantly. Meanwhile, the cell viability declined to 13.98% in 24 h at a concentration of 60 μg mL -1 and the IC 50 was 42.68 μg mL -1 . Moreover, the expression of Bcl-2 and GPX-4 proteins decreased in a time-dependent manner, indicating that DOX@7FZ was able to enhance the ROS level in cancer cells via a synergistic effect between apoptosis and ferroptosis. The mechanism of action of DOX@7FZ was further verified using hematoxylin and eosin staining and immunohistochemical staining of Bcl-2 and GPX-4. These remarkable characteristics of DOX@7FZ may inspire further advancements in the treatment of breast cancer.

Many effluents contain various antibiotics commonly, where the simultaneous removal of them is a big challenge. In this study, the magnetic biocomposite (eggshell-zeolitic imidazolate framework) was designed and synthesized by green and facile method. Zeolitic imidazolate framework-8 (ZIF-8) particles were stabilized on the surface of magnetic eggshell (Fe 3 O 4 -ES), generating a new Fe 3 O 4 -ES/ZIF-8 adsorbent, which was also fully characterized using FTIR, XRD, SEM and BET techniques. Thereafter, norfloxacin (NOR) adsorption processes were investigated through different influencing factors (dosage, concentration, pH and temperature). The Langmuir adsorption isotherm could confirm a maximum removal efficiency of 80.13% for NOR. Kinetic studies illustrated that the pseudo-first-order model was in line with the experimental data of the simultaneous removal of NOR. Moreover, the magnetic nature of the adsorbent caused an easy separation from the aqueous solution.

The correlation between magnetic relaxation dynamics and the alignment of single-ion magnets (SIMs) in a crystal was investigated using four analogous cobalt(ii) complexes with unique hydrogen-bond networks. The hydrogen-bonding interactions in the crystals resulted in a relatively short intermolecular Co⋯Co distance, which led to non-zero intermolecular magnetic coupling. All the complexes with a Co⋯Co distance shorter than 6.5 Å exhibited zero-field slow magnetic relaxation as weak magnetic interactions split the ground ±M s levels and suppressed quantum tunneling of magnetization (QTM). In particular, antiferromagnetically coupled one-dimensional chain SIM networks effectively suppressed QTM when the two intrachain Co⋯Co distances were non-equivalent. However, when the two distances in a chain were equivalent and each molecular symmetry axis aligned parallell within the chain, QTM suppression was insufficient because magnetic coupling from the adjacent molecules was virtually cancelled. Partial substitution of the Co II ion with the diamagnetic Zn II ion up to 33% for this complex resulted in complete QTM suppression in the absence of an external field. These results show that the manipulation of intermolecular distances and alignments is effective for suppressing undesired QTM events in SIMs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Pentakis(dimethylsulfoxide-κ O )oxidovanadium(iv) bis(tetraphenylborate), [VO(dmso) 5 ][BPh 4 ] 2 (dmso: dimethylsulfoxide), was synthesized, and its pseudo- C 4 VO 6 coordination geometry was revealed by a single-crystal X-ray method. A novel equation set was obtained for magnetic susceptibility and magnetization of the d 1 complexes, considering the axial distortion and the spin-orbit coupling for the 2 D free-ion term. The equation set enabled magnetic simulation for significantly symmetry-lowered d 1 complexes to obtain the anisotropic g -values and also the excitation energies. In addition, conformational prediction was conducted, using the enumeration results on the basis of the group theory. The dominant conformers were predicted on the basis of the density functional theory (DFT) method, and especially, the conformer in the crystal was successfully predicted by a deep neural network method., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The reactions of [Ru 2 (O 2 CCH 3 ) 4 Cl] with 2-aminopyridine (Hamp) and 2-amino-4-methylpyridine (Hammp) afforded two novel Ru 2 complexes, [Ru 2 (amp) 4 Cl 2 ] (1) and [Ru 2 (ammp) 4 Cl 2 ] (2), respectively. Single crystal X-ray diffraction analyses revealed that 1 and 2 adopted typical paddlewheel-type structures, where the Ru 2 units are coordinated with four aminopyridinate ligands with a cis-2:2 arrangement at the equatorial positions and two chloride ligands at the axial positions. The stabilities of 1 and 2 were supported by unrestricted density functional theory (uDFT) calculations. The zero-point energies of the three structural isomers (trans-2:2, 3:1, and 4:0 arrangements) of 1 and 2 were less stable than those of the respective cis-2:2 arrangements. Temperature-dependences of the magnetic susceptibility measurements and uDFT calculations showed that the oxidation and spin states of the Ru 2 units in 1 and 2 were commonly Ru 2 6+ and triplet states, respectively. Cyclic voltammetry showed that 1 and 2 underwent one-electron reduction processes, i.e., 1/1 - and 2/2 - , at redox potentials (E 1/2 ) of -0.08 and -0.18 V vs. SCE, respectively. These results agreed well with the DFT-calculated E 1/2 values of 1 (-0.08 V vs. SCE) and 2 (-0.18 V vs. SCE) and were theoretically attributed to Ru 2 -centred (δ*(Ru 2 )) redoxes. Moreover, 1 and 2 showed unique near-infrared absorption bands at approximately 1200-1500 nm, which were theoretically attributed to the ligand-to-metal charge transfer (LMCT) with π(amp or ammp) →δ*(Ru 2 ) transition characteristics.

The crystal structure of a new magnesium(ii) complex, [Mg(dmso) 6 ][BPh 4 ] 2 (1) (dmso: dimethylsulfoxide), was determined, and the reason for the observed structure was clarified by conformational analysis. For a dmso-ligand arm, three conformations, α, β, and γ, are possible. The α-arm is the most energetically favourable and is suitable for reducing the steric repulsion between the arms; the β-arm is less energetically favourable, but can be stabilized by interaction with surroundings (e.g. CHπ interaction); the γ-arm is not energetically favourable, but is effective in reducing the size of the complex cation. From the conformational analysis, the most stable conformer of the [Mg(dmso) 6 ] 2+ complex cation was found to be the α 6 conformer, and the complex cation in dmso solution was predicted to exist as a mixture of α 6 , α 5 β, and trans-α 4 β 2 species. On the contrary, in the crystal structure, the trans-β 2 γ 4 species, considered to be unstable, was observed. From the conformational analysis in the tetraphenylborate surroundings, the trans-β 2 γ 4 structure was found to become more stable, due to its small size suitable for crystal packing with bulky tetraphenylborate anions.

Three tetracoordinated cobalt(ii) complexes with a series of unsymmetrical bidentate ligands were synthesized and crystallographically characterized. Although their static magnetic properties are similar, their dynamic magnetic properties differ drastically depending indirectly on intermolecular hydrogen-bonding interactions.

The magnetostructural correlation of the hexakis-dmso cobalt(ii) complex, [Co(dmso) 6 ](BPh 4 ) 2 (dmso: dimethylsulfoxide), was investigated by single-crystal X-ray diffraction study and magnetic measurements. The magnetic analysis concluded the negative Δ value (H = Δ(L - 2/3) + E(L - L) - (3/2)κλL·S + β[-(3/2)κL u + g e S u ]·H u (u = x, y, z)), and this was explained by the tetragonal elongation of the octahedral geometry. The magnetostructural correlation was ascertained by both the angular overlap model calculation and the density functional theory calculation.

An unusual Cu(ii) coordination polymer [Cu(Him) 2 (L)] (1) having a 4,4'-{[1,2-phenylene bis-(methylene)]bis(oxy)}dibenzoic acid ligand and an imidazole ligand possessing a 1D zig-zag chain was constructed and its magnetic behaviour was investigated, which indicated a magnetic phase transition below 25 K as well as long-range magnetic ordering.

A large up-field shift (-763 ppm) has been observed for the carboxyl carbons of the dichlorido complex TBA[Ru(2)(O(2)CCH(3))(4)Cl(2)] (TBA(+) = tetra(n-butyl)ammonium cation) in the (13)C NMR spectrum (CD(2)Cl(2) at 25 °C). The DFT calculations showed spin delocalization from the paramagnetic Ru(2)(5+) core to the ligands, in agreement with the large up-field shift.

Two isoreticular metal-organic frameworks with chemical formulae [Cu(L)(4,4'-bipy)(H2O)]n 1.5nCH3CN (1) and [Cu(L)(4,4'-bipy)(H2O)]n·4nH2O (2) (H2L = diphenylmethane-4,4'-dicarboxylic acid) were synthesized and structurally characterized. They show the CdSO4 (6(5) 8) net and have an obvious 1D channel that is spread along the crystallographic c axis. More importantly, 1 shows high selectivity for H2 over N2 and CO2 at low pressure, which could be confirmed via computational calculations using the Connolly algorithm to reveal the size and shape of accessible voids. The incorporation of the drug 5-fluorouracil (5-FU) into the desolvated 1 was around 27.5 wt% per gram of the dehydrated 1. 5-FU is released in a highly controlled and progressive fashion with 61% of the drug released after 95 hours. In addition, we have applied molecular docking calculations to investigate the preferred conformation of 5-FU molecules upon binding to MOF 1. These calculations provide a structural basis to explain the 5-FU release from MOF 1.

Here we report a versatile magnetic susceptibility equation for tetranuclear octahedral high-spin cobalt(ii) complexes and a magnetic analysis for a tetranuclear defect cubane cobalt(ii) complex based on this equation. We concluded that the interaction is essentially ferromagnetic despite the decrease in the χT product on cooling from 300 K, and the decrease is due to the spin-orbit coupling.

The hydrothermal reaction of 2-pyrimidine-carboxamide, CoCl2.6H(2)O and K3[Co(CN)6] affords a novel mixed-valence Co(II)/Co(III) 3D complex K[Co3(CN)6(ox)(H(2)O)2].H2O, which contains cyano-bridged Co(7) defective cubanes connected by oxalate and cyanide bridging groups and behaves as a canted antiferromagnet with Tc = 17.5 K.

The isomorphous coordination polymers {micro-Au(CN)(2)](2)[(M(NH(3))(2))(2)(mu-bpym)]}[Au(CN)(2)](2) (M = Co(II) (1), Ni(II) (2), Cu(II) (3)) have been prepared from the reaction of 2 equiv. M(NO(3))(2) x nH(2)O (M = Cu(II), n = 3; M = Ni(II) and Co(II), n = 6) with 1 equiv. of bipyrimidine (bpym) in aqueous ammonia and then with an aqueous solution containing 1 equiv. of K[Au(CN)(2)]. The structures of these complexes are made of bpym bridged centrosymmetric dinuclear [M(NH(3))(2)(mu-bpym)M(NH(3))(2)] units connected by [Au(CN)(2)](-) anions to four other dinuclear units giving rise to a cationic 2D (4,4) rectangular grid network, its charge being balanced by two non-coordinated [Au(CN)(2)](-). The layers are stacked in such a way that the ammonia coordinated molecules are interdigitated and aligned above and below one sheet with cavities in neighbouring sheets, giving rise to an ABAB[dot dot dot] repeat pattern of layers. Gold atoms of bridging and non-bridging dicyanoaurate anions are involved in short aurophilic interactions (Au1-Au2 distances in the range 3.12-3.14 Angstrom), leading to a chain of gold atoms running along the a direction. Neighbouring gold chains are further connected by weaker aurophilic interactions (Au1-Au1 distances in the range 3.43-3.49 Angstrom), affording a honeycomb-like 2D network of gold atoms. The (4,4) rectangular sheets and (6,3) honeycomb sheets share the Au2 atoms, leading to a unique 3D network. Magnetic measurements clearly show the existence of antiferromagnetic exchange coupling between the metal ions with susceptibility maxima at 17 K (1), 22 K (2), and 17 K (3). The data of 1 were analyzed through a full Hamiltonian involving spin-orbit coupling, axial distortion, Zeeman interactions and magnetic exchange coupling between Co(II), and the best fit gives J = -9.23 cm(-1), kappa = 0.99, lambda = -142 cm(-1), Delta = -562 cm(-1). For 2 and 3, magnetic data were fitted to the theoretical equations derived from the isotropic Hamiltonian: H = -JS(1)S(2). The best fit parameters were g = 2.050(1), J = -17.51(1) and P = 0.01(2) for 2 and g = 2.068(5), J = -20.07(8) and P = 0.015(4) for 3, respectively (P takes into account the amount of paramagnetic impurity). In order to explain the weak magnetic interaction between copper(II) ions mediated by the bipyrimidine bridging ligand in 3, we have carried out electronic structure calculations based on the density functional theory (DFT).