European Journal of Inorganic Chemistry最新文献

Spin-crossover (SCO) effect on octahedral Co(II) centers is much rarer and less known than in the case of Fe(II) complexes, although it is no less promising for the development of fundamental research, sophisticated memories, and sensors. The representative compound [Co(terpy)₂]I₂ ⋅ 2H₂O (terpy=2,2′:6′,2′′-terpyridine) was synthesized, and its physicochemical properties were studied both experimentally and theoretically. Magnetic experiments revealed a very gradual SCO between a low-spin state (S_Co(II)-LS=1/2) and a high-spin state (S_Co(II)-HS=3/2) for the pristine sample and an abrupt SCO with a narrow thermal hysteresis around 130 K for the desolvated sample. Moreover, temperature-dependent vibrational and electronic spectroscopy were employed to track the evolution of spectroscopic features related to SCO and desolvation processes. Additionally, quantum chemical calculations were utilized to determine the electronic structure, molecular orbitals, and vibrations for different spin states at various temperatures, offering a more comprehensive understanding of the compound's spectroscopic and magnetic behaviors. These extensive investigations provide valuable insights into Co(II)-based SCO materials and their theoretical underpinnings, paving the way for the application of their thermometric properties.

Lewis acid/base-free diarylgermanethione 3 and diarylgermaneselenone 4 were synthesized through reactions of a heteroleptic diarylgermylene with elemental sulfur and selenium, respectively. They were fully characterized by structural, spectroscopic and computational methods. Germanethione underwent 1,2-addition with AlMe₃ at the Ge=S double to give Ge(IV) compound 5. The chalcogen atoms in 3 and 4 could coordinate to copper halide to yield Cu(I) complexes 6 and 7, respectively.

The Front Cover illustrates the synthesis of a family of pyrenyl-(NHC)MCl coinage metal complexes, M=Cu^I, Ag^I and Au^I, (NHC=N-heterocyclic carbene). These compounds are stable and were obtained in high yields. The molecular structures of all complexes were ascertained by X-ray diffraction studies. The use of the chromophoric-(NHC) ligand endows these complexes with emissive properties in the blue region at a similar wavelength to the magical natural blue light created by phytoplankton on the surface of the ocean at nightfall. More information can be found in the Research Article by H. Amouri and co-workers.

Rubidium manganese hexacyanidoferrate, Rb_0.97Mn[Fe(CN)₆]_0.99 ⋅ 0.5H₂O, which has a three-dimensional cyanido-bridged Mn−Fe framework encapsulating Rb⁺ ions, shows a terahertz (THz) wave absorption property. This compound undergoes a charge-transfer phase transition between Fe^III-CN-Mn^II [high temperature (HT) phase] and Fe^II-CN-Mn^III [low temperature (LT) phase] near room temperature. The HT phase exhibits a THz wave absorption at 1.06 THz due to the slow vibration of the heavy Rb⁺ ions encapsulated in the three-dimensional framework. By contrast, the LT phase displays a higher resonance frequency at 1.13 THz. This shift to a higher frequency is attributed to the framework shrinkage, which decreases the space available for the trapped Rb⁺ ion. Indeed, the void volume accompanying the phase transition decreases by 16.4 % from 41.4 ų (HT phase) to 34.6 ų (LT phase). Tuning the THz wave absorption frequency is necessary for THz devices such as absorbers, switches, filters, and modulators, especially for THz technology with THz waves in the sub-THz region or near 1 THz.

Chiral 1D coordination compounds formed by association of either of the enantiomers of [ML(MeOH)Cl]Cl (with M=Mn^II or Fe^II; L stands for either R or S enantiomer of a pentadentate macrocycle) and NBu₄[Fe^III(bpb)(CN)₂], namely: 1D-[{Fe^III(bpb)(CN)₂}{M^II(L^R)}](PF₆) and 1D-[{Fe^III(bpb)(CN)₂}{M^II(L^S)}](PF₆) with M=Mn (2R, 2S) and Fe (3R, 3S). The bis(triphenylphosphine)iminium salt of the metallo-ligand, PNP[Fe^III(bpb)(CN)₂]⋅2H₂O, 1 b, is also described. Their preparations, crystal structures, optical and magnetic properties are reported. Mössbauer spectroscopy confirmed the oxidation state in the [Fe^II−Fe^III] chain, for which AC susceptibility suggests SCM behavior, but for very low T.

We report three novel lithium zincate alkoxo clusters, which can be accessed through a convenient co-complexation reaction of the corresponding dialkylzinc derivatives with lithium alkoxides of the formula [LiO(CH₂)₂N(CH₃)₂], or via a deprotonation process mediated by the higher-order zincate Li₂ZnEt₄ and dimethylethanolamine. These complexes have been isolated as colourless crystalline solids and characterised by multinuclear magnetic resonance spectroscopy, elemental and single-crystal X-ray diffraction analysis. XRD analysis of the crystal structures, combined with ¹H DOSY NMR experiments, was crucial for understanding the chemistry behind these complexes. Furthermore, complexes obtained by mixing ZnEt₂ with a chiral nonracemic lithium alkoxide generated from (1R,2S)-N-methylephedrine have been explored in promoting an enantioselective Michael addition reaction towards trans-β-nitrostyrene, with the corresponding nitroalkane isolated in up to 37.3 % enantiomeric excess.

This contribution is dedicated to the analysis of the size and interaction parameters effects on the thermal properties of square-shaped cross-spin transition core-shell nanoparticles. The present study is carried out by varying the shell size at fixed core size and vice versa. In this problem, the core and shell are active from the spin transition point of view, while having different properties in terms of ligand field (transition temperatures) and interactions. The resulting nanoparticle is described by an Ising-type model including the three interaction parameters J_CC, J_SS and J_CS coupling core-core, shell-shell and core-shell sites, respectively. The thermodynamic investigations have been carried out in 3 different ways: (i) by Monte Carlo Entropic Sampling (MCES) for small size nanoparticles ($$) (ii) by usual Monte Carlo Metropolis for higher dimensions (iii) by an analytical method deducing the equilibrium temperature of the system from the various local environments. We demonstrate that, as long as a clear plateau region occurs in the thermal-dependence of the high-spin fraction, an excellent agreement is obtained, allowing to predict analytically the evolution of the transition temperatures. The limitations of the method are discussed in the case of strong interference between the thermal dependences of the core and shell.

Benzoate substituted with a cationic quaternary ammonium group at the para-position, [4-(CH₃)₃N(C₆H₄)CO₂], forms mononuclear alkali metal ion complexes, [4-(CH₃)₃N(C₆H₄)CO₂M]⁺ (M=Li, Na, K, Rb and Cs), which are observed by electrospray-ionisation mass spectrometry. When mass selected and subjected to collision-induced dissociation each of these complexes undergoes decarboxylation to produce the mononuclear arylalkali complex cations, [4-(CH₃)₃N(C₆H₄)M]⁺, which subsequently react with water via hydrolysis to yield the quaternary ammonium cation, (CH₃)₃NC₆H₅⁺. The unexpected product ions, [M((CH₃)₂NC₆H₅)]⁺, [M(CH₃OH)]⁺, and M⁺, which are associated with the hydrolysis pathway, suggest an unusual reaction occurring within the exit channel ion-molecule complex, [(CH₃)₃NC₆H₅+MOH]⁺. DFT calculations were used to examine the: decarboxylation reaction of [4-(CH₃)₃N(C₆H₄)CO₂M]⁺, which readily proceeds via a four-centred transition state; the hydrolysis and S_N2 reactions accounting for formation of products in the exit channel, which are connected via a roaming mechanism in which the metal hydroxide moiety migrates from the para-hydrogen of (CH₃)₃NC₆H₅⁺ to one of the methyl groups.

Perfluorinated β-diketones form chelation complexes with rare earth and transition metals. Six heterocyclic dicarbonyl ligands demonstrate chelation activity toward Th^IV at acidic pH in aqueous solution. The “true” stability constants lie in the range 6.2–6.8 logarithmic units and are much greater than for lanthanide complexes. A significant bathochromic shift between the maximum absorption wavelength of lanthanide and actinide monocomplexes of β-diketones was detected. The spectral shift increases with the atomic number of the substituted chalcogen atom in the heterocyclic ring of the corresponding ligand. More information can be found in the Research Article by M. A. Lutoshkin and co-workers.

Hybrid materials, such as metal organic nanotubes (MONTs) can possess nanoconfined water molecules within their pore space and the overall behavior of the water within the material may be tuned based upon interactions with the inner channel walls. We have previously developed a range of methods (electron density mapping, kinetic models, and water interaction enthalpies) to evaluate water behavior under nanoconfinement using a uranium-based metal organic nanotube (UMONT) but have not explored their applicability across a range of materials. In the current study, we test our methodologies on two additional MONT materials (LaMONT and Cu-LaMONT) to determine if the techniques can be utilized in other systems to predict behavior within complex hybrid materials. In addition, we explored how to use Hirshfeld surface maps generated by the CrystalExplorer software in the visualization and prediction of water behavior within complex hybrid materials.