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The syntheses, coordination chemistry, and Mössbauer spectroscopy of hepta-iron(III) complexes using derivatised salicylaldoxime ligands from two categories; namely, 'single-headed' (H 2 L ) and 'double-headed' (H 4 L ) salicylaldoximes are described. All compounds presented here share a [Fe 3 -µ 3 -O] core in which the iron(III) ions are µ 3 -hydroxo-bridged in the complex C1 and µ 3 -oxo-bridged in C2 and C3 . Each compound consists of 2 × [Fe 3 -µ 3 -O] triads that are linked via a central [Fe(µ 2 -OH) 6 ] 3- ion. In addition to the charge balance and microanalytical evidence, Mössbauer measurements support the fact that the triads in C1 are µ 3 -OH bridged and are µ 3 -O bridged in C2 and C3 .

In the quest for optimal H 2 evolution (HE) through ethanol photoreforming, a dual cocatalyst-modified heterocatalyst strategy is utilized. Tin(II) sulfide (SnS) was hybridized with α-Fe 2 O 3 to form the heterocatalyst FeOSnS with a p-n heterojunction structure as confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffusive reflectance spectroscopy (UV-vis DRS), and Brunauer-Emmett-Teller (BET) techniques. PdO x and PdO x /MnO x cocatalysts were loaded onto the FeOSnS heterocatalyst through the impregnation method, as verified by high-resolution transform electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and elemental mapping. Photocatalytic ethanol photoreforming resulted in the production of H 2 as the main product with a selectivity of 99% and some trace amounts of CH 4 . The FeOSnS2-PdO x 2%/MnO x 1% photocatalyst achieved the highest HE rate of 1654 μmol/g, attributed to the synergistic redox contribution of the PdO x and MnO x species., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Conditions have been identified in which phenolic aldoximes and ketoximes of the types used in commercial solvent extraction processes can be doubly deprotonated and generate polynuclear Cu complexes with lower extractant:Cu molar ratios than those found in commercial operations. Electrospray mass spectrometry has provided an insight into the solution speciation in extraction experiments and has identified conditions to allow isolation and characterization of polynuclear Cu-complexes. Elevation of pH is effective in enhancing the formation of trinuclear complexes containing planar {Cu 3 -μ 3 -O} 4+ or {Cu 3 -μ 3 -OH} 5+ units. DFT calculations suggest that such trinuclear complexes are more stable than other polynuclear species. Solid structures of complexes formed by a salicylaldoxime with a piperidino substituent ortho to the phenolic OH group ( L 9 H 2 ) contain two trinuclear units in a supramolecular assembly, {[Cu 3 OH( L 9 H) 3 (ClO 4 )](ClO 4 )} 2 , formed by H-bonding between the central {Cu 3 -μ 3 -OH} 5+ units and oxygen atoms in the ligands of an adjacent complex. Whilst the lower ligand:Cu molar ratios provide more efficient Cu-loading in solvent extraction processes, the requirement to raise the pH of the aqueous phase to achieve this will make it impractical in most commercial operations because extraction will be accompanied by the precipitation (as oxyhydroxides) of Fe(III) which is present in significant quantities in feed solutions generated by acid leaching of most Cu ores.

Four tetranuclear heterobimetallic triangle complexes [L 3 Co 3 Dy(NO 3 ) 2 (H 2 O)(MeOH) 5 ](NO 3 ) (C1), [L 3 Co 3 Gd(NO 3 ) 3 (MeOH) 4 ] (C2), [L 3 Co 3 La(NO 3 ) 2 (H 2 O) 6 ](NO 3 )(H 2 O) (C3), and [L 3 Co 3 TbCl(NO 3 ) 2 (H 2 O) 0.5 (MeOH) 3.5 ] (C4), where H 2 L = 1,4-bisformylnaphthalene-2,3-diol, have been synthesised and structurally characterised. Each complex crystallises with a complete molecule in the asymmetric unit ( Z ' = 1) and displays near perfect octahedrality in two out of three Co II centres. The third Co II ion assumes a different coordination geometry in each complex: six-coordinate octahedral in C1, six-coordinate with a distortion towards trigonal prismatic in C2, five-coordinate trigonal bipyramidal in C3, and five-coordinate square pyramidal in C4; which has been attributed to increasing lanthanide cation size, coupled with a non-macrocyclic coordination environment. Continuous Shape Measurement (CShM) calculations and octahedral distortion parameter calculations were performed, using the SHAPE and OctaDist software packages, respectively, in order to aid in the assessment of each metal centre's local coordination geometry. The preliminary magnetic investigation of C3 found χ m T = 9.4 cm 3 K mol -1 at 300 K and M = 7.1 μ B at 1.8 K, which are approximately two thirds the maximum theoretical values for three Co II ions and indicates the presence of a relatively large zero-field splitting parameter ( D / k B = 65 K) operative in each Co II ion rather than exchange coupling between the Co II centres., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

We report the synthesis and characterization of seven new tetranuclear 3d-4f complexes derived from the 3:3:1 reaction of 1,4-diformylnaphthalene-2,3-diol (H 2 L ) with copper(II) nitrate and a lanthanide salt, Ln = Tb [ L 3 Cu 3 TbCl 2 (NO 3 ) 2 (H 2 O) 2 ] ( C1 ), Ho [ L 3 Cu 3 HoCl 3 (H 2 O) 3 (MeOH)](H 2 O) ( C2 ), Er [ L 3 Cu 3 ErCl 3 (H 2 O) 3.5 (MeOH) 0.5 ](H 2 O) ( C3 ), Gd [ L 3 Cu 3 Gd(NO 3 ) 2 (H 2 O) 2 (MeOH)](NO 3 ) ( C4 ), Dy [ L 3 Cu 3 Dy(NO 3 ) 2 (H 2 O) 2 (MeOH)](NO 3 ) ( C5 ), Yb [ L 3 Cu 3 Yb(NO 3 ) 2 (H 2 O) 2 (MeOH)](NO 3 ) ( C6 ), and La [ L 3 Cu 3 La(NO 3 ) 2 (H 2 O) 2 (MeOH)](NO 3 ) ( C7 ). Structural elucidation showed that the self-assembly using the acyclic ligand system was successful for all seven complexes, which exhibit the same near-planar Cu 3 LnO 12 core. Five complexes ( C1 , C2 , and C4 - C6 ) were magnetically characterized at 300 K and 1.8 K. Complexes C1 , C4 , and C5 were observed to have ferromagnetic ground states and showed appreciable frequency dependence in their AC magnetic measurements, which yielded effective barriers between 7.82(4) and 13.2(3) K, confirming the presence of single-molecule magnet properties., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Cu I complexes containing the bulky dialkylbiarylphosphane 2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl ( t BuXPhos, L) and an ancillary ligand (Cl - , Br - , I - , MeCN, ClO 4 - or SCN - ) have been structurally characterized, namely, chlorido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuCl(C 29 H 45 P)], 1, bromido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuBr(C 29 H 45 P)], 2, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]iodidocopper(I), [CuI(C 29 H 45 P)], 3, (acetonitrile-κN)[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I) hexafluoridophosphate, [Cu(CH 3 CN)(C 29 H 45 P)]PF 6 , 4, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP](perchlorato-κO)copper(I), [Cu(ClO 4 )(C 29 H 45 P)], 5, and di-μ-thiocyanato-κ 2 S:N;κ 2 N:S-bis{[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I)}, [Cu 2 (NCS) 2 (C 29 H 45 P) 2 ], 6. Iodide complex 3 shows significant Cu I -arene interactions, in contrast to its chloride 1 and bromide 2 counterparts, which is attributed to the weaker interaction between the iodide ion and the Cu I centre. When replacing iodide with an acetonitrile (in 4) or perchlorate (in 5) ligand, the reduced interaction between the Cu I atom and the ancillary ligand results in stronger Cu I -arene interactions. No Cu I -arene interactions are observed in dimer 6, due to the tricoordinated Cu I centre having sufficient electron density from the coordinated ligands.

Substituted [2.2]metaparacyclophanes are amongst the least studied of the simple cyclophanes. This is undoubtedly the result of the lengthy syntheses of these compounds. We report the simple synthesis of a rare example of a non-symmetric [2.2]metaparacyclophane. Treatment of [2.2]paracyclophane under standard nitration conditions gives a mixture of 4-nitro[2.2]paracyclophane, 4-hydroxy-5-nitro[2.2]metaparacyclophane and a cyclohexadienone cyclophane., (Copyright © 2021, Patel et al.)

Syntheses and magnetic and structural characterization of hexa-iron complexes of derivatized salicylaldoximes are discussed. Complexation of Fe(BF 4 ) 2 ·6H 2 O with each ligand (H 2 L1 and H 4 L2 ) in a methanolic-pyridine solution resulted in hexa-iron compounds ( C1 and C2 , respectively), which each contain two near-parallel metal triangles of [Fe 3 -μ 3 -O], linked by six fluoride bridges and stabilized by a hydrogen-bonded proton between the μ 3 -O groups. Within each metal triangle of C2 , Fe(III) ions are connected via the amine "straps" of (H 4 L2 -2H). Variable-temperature magnetic susceptibility and Mössbauer data of C1 and C2 indicate the presence of dominant antiferromagnetic interactions between the high-spin ( S = 5/2) Fe(III) centers. For C1 , two quadrupole doublets are observed at room temperature and 5 K, consistent with structural data from which discrete but disordered [Fe 3 -μ 3 -O] and [Fe 3 -μ 3 -OH] species were inferred. For C2 , a single sharp quadrupole doublet with splitting intermediate between those determined for C1 was observed, consistent with the symmetric [Fe 3 -μ 3 -O···H···μ 3 -O-Fe 3 ] species inferred crystallographically from the very short μ 3 -O···μ 3 -O separation. The differences in the physical properties of the complexes, as seen in the Mössbauer, X-ray, and magnetic data, are attributed to the conformational flexibility imparted by the nature of the linkages between the closely related ligands., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

A comparative study between three experimentally known beryllium chelators (EDTA, NTP, and 10-HBQS) and two tetradentate tripodal di-pyridine-based receptors (HL and HL-NH 2 ), specifically designed to bind Be 2+ cations, has been undertaken in the aqueous phase at the B3LYP/6-311++G(d,p) computational level. The relative binding energies of these five ligand systems to a variety of first row and pre-transition metal cations have been calculated, specifically to investigate their binding strength to Be 2+ and the binding enhancement that a second sphere hydrogen bonding interaction could afford to the pyridyl based systems. The complexes of EDTA were calculated to have the highest average binding energy; followed by those of NTP, HL-NH 2 , HL, and finally 10-HBQS. The calculated binding energy of the HL-NH 2 Be complex, which includes second sphere interactions, was found to be almost 9% greater than the HL Be complex, with an average binding energy increase of 13.5% observed across all metals upon inclusion of second sphere hydrogen bonding., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Quinolino[7,8- h ]quinoline is a superbasic compound, with a p K aH in acetonitrile greater than that of 1,8-bis(dimethylaminonaphthalene) (DMAN), although its synthesis and the synthesis of its derivatives can be problematic. The use of halogen derivatives 4,9-dichloroquinolino[7,8- h ]quinoline ( 16 ) and 4,9-dibromoquinolino[7,8- h ]quinoline ( 17 ) as precursors has granted the formation of a range of substituted quinolinoquinolines. The basicity and other properties of quinolinoquinolines can be modified by the inclusion of suitable functionalities. The experimentally obtained p K aH values of quinolino[7,8- h ]quinoline derivatives show that N 4 , N 4 , N 9 , N 9 -tetraethylquinolino[7,8- h ]quinoline-4,9-diamine ( 26 ) is more superbasic than quinolino[7,8- h ]quinoline. Computationally derived p K aH values of quinolinoquinolines functionalized with dimethylamino (NMe 2 ), 1,1,3,3-tetramethylguanidino (N═C(NMe 2 ) 2 ) or N , N , N ', N ', N ″, N ″-hexamethylphosphorimidic triamido (N═P(NMe 2 ) 3 ) groups are significantly greater than those of quinolino[7,8- h ]quinoline. Overall, electron-donating functionalities are observed to increase the basicity of the quinolinoquinoline moiety, while the substitution of electron-withdrawing groups lowers the basicity.

In the quest for optimal heat dissipaters for magnetic fluid hyperthermia applications, monodisperse M x Fe 3- x O 4 (M = Fe, Mg, Zn) spinel nanoferrites were successfully synthesized through a modified organic-phase hydrothermal route. The chemical composition effect on the size, crystallinity, saturation magnetization, magnetic anisotropy, and heating potential of prepared nanoferrites were assessed using transmission electron microscopy (TEM), dynamic light scattering, X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDS), atomic absorption spectroscopy (AAS), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM) techniques. TEM revealed that a particle diameter between 6 and 14 nm could be controlled by varying the surfactant ratio and doping ions. EDS, AAS, XRD, and XPS confirmed the inclusion of Zn and Mg ions in the Fe 3 O 4 structure. Magnetization studies via VSM revealed both the superparamagnetic nature of the nanoferrites and the dependence on substitution of the doped ions to the final magnetization. The broader zero-field cooling curve of Zn-doped Fe 3 O 4 was related to their large size distribution. Finally, a maximum rising temperature ( T max ) of 66 °C was achieved for an aqueous ferrofluid of nondoped Fe 3 O 4 nanoparticles after magnetic field activation for 12 min., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

In the title complex, [Cu(BF4)2(C5H5N)2], the Cu(II) ion is in an octa-hedral coordination environment and is surrounded by four pyridine and two tetra-fluoridoborate mol-ecules. The four pyridine mol-ecules are coordinated to the copper ion through their N atoms in the equatorial plane and display a right-handed screw arrangement around the Cu(II) ion. The remaining two trans positions in the octa-hedron are occupied by the BF4 (-) anions, each coordinating weakly through an F atom. The crystal packing shows a two-dimensional sheet structure parallel to the ab plane that is formed by C-H⋯F hydrogen-bonding inter-actions.

Structure analysis of the title compound, C(9)H(6)BrNO, has established that bromination of an 8-hydroxyquinoline derivative occurred in the 7-position. Intermolecular and weak intramolecular O-H.N hydrogen bonds are present, the former causing the molecules to pack as hydrogen-bonded dimers in the solid state.