Low-Temperature Ferromagnetic Order in a Two-Level Layered Co Material.

The magnetic properties of a 2D layered material consisting of high-spin Co complexes, [Co(NHNH)(HO)Cl]Cl ( ), have been extensively characterized using electron paramagnetic resonance, magnetic susceptibility, and low-temperature heat capacity measurements. Electron paramagnetic resonance spectroscopy studies suggest that below 50 K, the = 3/2 orbital triplet state of Co is gradually depopulated in favor of the = 1/2 spin state, which is dominant below 20 K. In light of this, the magnetic susceptibility has been fitted with a two-level model, indicating that the interactions in this material are much weaker than previously thought.

Tuneable stimuli-responsive behaviour, spectroscopic signatures and redox properties of indolo[3,2-]carbazole-based diradicals.

During the last decade, there has been an increasing interest in the rationalisation of how structural changes stabilise (or destabilise) diradical systems. Demonstrated herein is that indolocarbazole (ICz) diradicals, substituted with dicyanomethylene (DCM) groups, are useful motifs for dynamic covalent chemistry by self-assembling from isolated monomers to cyclophane structures. The comparison of ICz-based systems substituted with DCM groups in - or -positions (p-ICz-CN and m-ICz-CN) and their short-chain carbazole analogues (p-Cz-CN and m-Cz-CN) may identify new potential design strategies for stimuli-responsive materials.

δ-Bonding modulates the electronic structure of formally divalent nd rare earth arene complexes.

Landmark advances in rare earth (RE) chemistry have shown that divalent complexes can be isolated with non-Aufbau 4f {5d/6s} electron configurations, facilitating remarkable bonding motifs and magnetic properties. We report a series of divalent bis-tethered arene complexes, [RE(NHAr )] (2RE; RE = Sc, Y, La, Sm, Eu, Tm, Yb; NHAr = {N(H)CH-2,6-(CH-2,4,6-Pr)}). Fluid solution EPR spectroscopy gives < 2.

Analysis of a Cu-Doped Metal-Organic Framework, MFM-520(Zn Cu ), for NO Adsorption.

MFM-520(Zn) confines dimers of NO with a high adsorption of 4.52 mmol g at 1 bar at 298 K. The synthesis and the incommensurate structure of Cu-doped MFM-520(Zn) are reported.

Correction: Synthesis and characterization of heterometallic rings templated through alkylammonium or imidazolium cations.

Correction for 'Synthesis and characterization of heterometallic rings templated through alkylammonium or imidazolium cations' by Rajeh Alotaibi , , 2023, , 7473-7481, https://doi.org/10.1039/D3DT00982C.

Application of a Synthetic Ferredoxin-Inspired [4Fe4S]-Peptide Maquette as the Redox Partner for an [FeFe]-Hydrogenase.

'Bacterial-type' ferredoxins host a cubane [4Fe4S] cluster that enables these proteins to mediate electron transfer and facilitate a broad range of biological processes. Peptide maquettes based on the conserved cluster-forming motif have previously been reported and used to model the ferredoxins. Herein we explore the integration of a [4Fe4S]-peptide maquette into a H -powered electron transport chain.

Highly selective CO photoreduction to CO on MOF-derived TiO.

Metal-Organic Framework (MOF)-derived TiO, synthesised through the calcination of MIL-125-NH, is investigated for its potential as a CO photoreduction catalyst. The effect of the reaction parameters: irradiance, temperature and partial pressure of water was investigated. Using a two-level design of experiments, we were able to evaluate the influence of each parameter and their potential interactions on the reaction products, specifically the production of CO and CH.

Synthesis and characterization of heterometallic rings templated through alkylammonium or imidazolium cations.

We report the synthesis and structural characterization of a series of heterometallic rings templated alkylammonium or imidazolium cations. The template and preference of each metal's coordination geometry can control the structure of heterometallic compounds, leading to octa-, nona-, deca-, dodeca-, and tetradeca-metallic rings. The compounds were characterized by single-crystal X-ray diffraction, elemental analysis, magnetometry, and EPR measurements.

Structural and Functional Diversity in Rigid Thiosemicarbazones with Extended Aromatic Frameworks: Microwave-Assisted Synthesis and Structural Investigations.

The long-standing interest in thiosemicarbazones (TSCs) has been largely driven by their potential toward theranostic applications including cellular imaging assays and multimodality imaging. We focus herein on the results of our new investigations into: (a) the structural chemistry of a family of rigid mono(thiosemicarbazone) ligands characterized by extended and aromatic backbones and (b) the formation of their corresponding thiosemicarbazonato Zn(II) and Cu(II) metal complexes. The synthesis of new ligands and their Zn(II) complexes was performed using a rapid, efficient and straightforward microwave-assisted method which superseded their preparation by conventional heating.

Synthesis and characterisation of Ga- and In-doped CdS by solventless thermolysis of single source precursors.

We report a facile and low temperature synthesis of Ga- and In-doped CdS nanoparticles from molecular precursors. Diethyldithiocarbamate complexes of Cd(II), Ga(III), and In(III), were synthesised and decomposed in tandem through solventless thermolysis, producing Ga- or In-doped CdS. The resultant MCdS (where M = Ga/In at values of 0, 0.

Decorating polymer beads with 10 inorganic-organic [2]rotaxanes as shown by spin counting.

Polymer beads have been used as the core of magnetic particles for around twenty years. Here we report studies to attach polymetallic complexes to polymer beads for the first time, producing beads of around 115 microns diameter that are attached to 10 hybrid inorganic-organic [2]rotaxanes. The bead is then formally a [10] rotaxane.

Templating metallocycles with a macrocycle: synthesis, structures and magnetic studies of {CrM} complexes.

Addition of 1,4,8,11-tetrazacyclotetradecane (cyclam) to a reaction that produces octametallic rings when simpler amines are used, produces {CrM} "pretzels" (M = Zn or Cu) where the cyclam coordinates to the M ion which then sits at the centre of a twelve-metal macrocycle. Magnetic studies were fitted using the finite-temperature Lanczos method (FTLM), and the results demonstrate that exchange interactions are transferable from previous exchange-coupled Cr rings.

Magnetic and Electronic Structural Properties of the S State of Nature's Water Oxidizing Complex: A Combined Study in ELDOR-Detected Nuclear Magnetic Resonance Spectral Simulation and Broken-Symmetry Density Functional Theory.

ELDOR-detected nuclear magnetic resonance (EDNMR) spectral simulations combined with broken-symmetry density functional theory (BS-DFT) calculations are used to obtain and to assign the Mn hyperfine coupling constants (hfcs) for modified forms of the water oxidizing complex in the penultimate S state of the water oxidation cycle. The study shows that an open cubane form of the core MnCaO cluster explains the magnetic properties of the dominant = 3 species in all cases studied experimentally with no need to invoke a closed cubane intermediate possessing a distorted pentacoordinate Mn ion as recently suggested. EDNMR simulations found that both the experimental bandwidth and multinuclear transitions may alter relative EDNMR peak intensities, potentially leading to incorrect assignment of hfcs.

Modelling Conformational Flexibility in a Spectrally Addressable Molecular Multi-Qubit Model System.

Dipolar coupled multi-spin systems have the potential to be used as molecular qubits. Herein we report the synthesis of a molecular multi-qubit model system with three individually addressable, weakly interacting, spin centres of differing g-values. We use pulsed Electron Paramagnetic Resonance (EPR) techniques to characterise and separately address the individual electron spin qubits; Cu , Cr Ni ring and a nitroxide, to determine the strength of the inter-qubit dipolar interaction.

Structural Investigations of α-MnS Nanocrystals and Thin Films Synthesized from Manganese(II) Xanthates by Hot Injection, Solvent-Less Thermolysis, and Doctor Blade Routes.

Manganese(II) xanthate complexes of the form [Mn(SCOR)(TMEDA)], where TMEDA = tetramethylethylenediamine and R = methyl (), ethyl (), -propyl (), -butyl (), -pentyl (), -hexyl (), and -octyl (), have been synthesized and structures elucidated using single-crystal X-ray diffraction. Complexes - were used as molecular precursors to synthesize manganese sulfide (MnS). Olelyamine-capped nanocrystals have been produced hot injection, while the doctor blading followed by thermolysis yielded thick films.

Single Isomer Heterometallic {CrM} Rings Templated by Tetramethylammonium.

A family of heterometallic rings [MeN][CrMF(OCBu)] is reported using tetramethylammonium hydroxide pentahydrate as the source of a template, where M = Zn, Mn, Ni, and Co. The metal cores are octagons with metal-metal edges bridged by one fluoride and two carboxylate ligands. The divalent metal ions are found ordered at positions 1 and 5 in the octagon.

Substituent effects on through-space intervalence charge transfer in cofacial metal-organic frameworks.

Electroactive metal-organic frameworks (MOFs) are an attractive class of materials owing to their multifunctional 3-dimensional structures, the properties of which can be modulated by changing the redox states of the components. In order to realise both fundamental and applied goals for these materials, a deeper understanding of the structure-function relationships that govern the charge transfer mechanisms is required. Chemical or electrochemical reduction of the framework [Zn(BPPFTzTz)(tdc)]·2DMF, hereafter denoted ZnFTzTz (where BPPFTzTz = 2,5-bis(3-fluoro-4-(pyridin-4-yl)phenyl)thiazolo[5,4-]thiazole), generates mixed-valence states with optical signatures indicative of through-space intervalence charge transfer (IVCT) between the cofacially stacked ligands.

Synthesis, X-ray Single-Crystal Structural Characterization, and Thermal Analysis of Bis(O-alkylxanthato)Cd(II) and Bis(O-alkylxanthato)Zn(II) Complexes Used as Precursors for Cadmium and Zinc Sulfide Thin Films.

This work investigates tuning of the molecular structure of a series of O-alkylxanthato zinc and cadmium precursor complexes to enhance production of ZnS and CdS materials. The structures of several bis(O-alkylxanthato) cadmium(II) complexes (-) and bis(O-alkyl xanthato)zinc(II) complexes ( and ) are reported based on single crystal X-ray diffraction data. CdS and ZnS films were produced by the spin-coating of these metal complexes followed by their thermal decomposition to the corresponding metal sulfides.

Gold(i) bridged dimeric and trimeric heterometallic {CrNi}-based qubit systems and their characterization.

Gold(i) bridged dimeric and trimeric structures of a ground state spin S = 1/2 heterometallic {CrNi} wheel have been prepared and studied by continuous wave (CW) and pulsed wave EPR spectrometry. The {CrNi} relaxation time constants (T and T) show rates matching well with previous observations. Four pulse Double Electron Resonance (DEER) studies suggest presence of more than one conformations.

The Synthesis and Characterisation of a Molecular Sea-Serpent: Studies of a {Cr Cu } Chain.

A finite chain of thirty-one paramagnetic centers is reported, synthesized by reaction of hydrated chromium fluoride, copper carbonate and pivalic acid in the presence of 1,4,7,10-tetrazacyclododecane (cyclen). Magnetic studies show predominantly anti-ferromagnetic exchange leading to a high density of low-lying spin states and large saturation field.

Coupled NMR and EPR Studies Reveal the Electron Transfer Rate and Electrolyte Decomposition in Redox Flow Batteries.

We report the development of () EPR and coupled EPR/NMR methods to study redox flow batteries, which are applied here to investigate the redox-active electrolyte, 2,6-dihydroxyanthraquinone (DHAQ). The radical anion, DHAQ, formed as a reaction intermediate during the reduction of DHAQ, was detected and its concentration quantified during electrochemical cycling. The fraction of the radical anions was found to be concentration-dependent, the fraction decreasing as the total concentration of DHAQ increases, which we interpret in terms of a competing dimer formation mechanism.

Heterometallic 3d-4f Complexes as Air-Stable Molecular Precursors in Low Temperature Syntheses of Stoichiometric Rare-Earth Orthoferrite Powders.

Four 3d-4f hetero-polymetallic complexes [FeLn((OCH)CR)(OCBu)(HO)] (where Ln = La ( and ) and Gd ( and ); and R = Me ( and ) and Et ( and )) are synthesized and analyzed using elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, and SQUID magnetometry. Crystal structures are obtained for both methyl derivatives and show that the complexes are isostructural and adopt a defective dicubane topology. The four heavy metals are connected with two alkoxide bridges.

Quantification of the mixed-valence and intervalence charge transfer properties of a cofacial metal-organic framework single crystal electronic absorption spectroscopy.

Gaining a fundamental understanding of charge transfer mechanisms in three-dimensional Metal-Organic Frameworks (MOFs) is crucial to the development of electroactive and conductive porous materials. These materials have potential in applications in porous conductors, electrocatalysts and energy storage devices; however the structure-property relationships pertaining to charge transfer and its quantification are relatively poorly understood. Here, the cofacial Cd(ii)-based MOF [Cd(BPPTzTz)(tdc)]·2DMF (where BPPTzTz = 2,5-bis(4-(pyridin-4-yl)phenyl)thiazolo[5,4-]thiazole, tdc = 2,5-thiophene dicarboxylate) exhibits Intervalence Charge Transfer (IVCT) within its three-dimensional structure by virtue of the close, cofacial stacking of its redox-active BPPTzTz ligands.

Accessing γ-GaS by solventless thermolysis of gallium xanthates: a low-temperature limit for crystalline products.

Alkyl-xanthato gallium(iii) complexes of the form [Ga(SCOR)], where R = Me (1), Et (2), Pr (3), Pr (4), Bu (5), Bu (6) and Bu (7), have been synthesized and fully characterised. The crystal structures for 1 and 3-7 have been solved and examined to elucidate if these structures are related to their decomposition. Thermogravimetric analysis was used to gain insight into the decomposition temperatures for each complex.