Mn2+-doped perovskite nanocrystals (NCs) have recently emerged as promising phosphors for wide-gamut displays and white light-emitting diodes (WLEDs). In addition to their promising optical properties, these materials offer an environmental advantage: Mn replaces toxic Pb in perovskite structure, mitigating concerns associated with lead-based functional materials. This work investigates the optical properties of CsPb1-xMnxCl3 nanocrystals with high manganese content, reaching a molar fraction (x) of up to 0.68 (68%). We show that increasing Mn2+ concentration systematically widens the bandgap of these NCs, leading to a blueshift in the absorption edge and a corresponding shift in the excitonic photoluminescence (PL). The Mn2+-related emission band centered at similar to 600 nm remained stable, exhibiting a spectral redshift of less than 10 nm across the entire concentration series. The full PL intensity stayed nearly constant within the 80-300 K temperature range, highlighting the improved temperature stability of Mn-rich NCs.

Drugs and drug candidate compounds commonly suffer from poor solubility and permeability. One promising strategy to mediate these drawbacks is use of novel solvents, such as deep eutectic compositions. The present research aims to determine the applicability of this approach for therapeutic metal complexes on the example of [Cu(Fur)2(Phen)] (Fur = furoate-anion, Phen = 1,10-phenantroline) and [Cu(Fur)2(Neoc)(H2O)] (Fur = furoate-anion, Neoc = 2,9-dimetyl-1,10-phenanthroline) with molar weight of appx. 500 Da. Interaction of the metal complexes with the deep eutectic solvent (DES) reline was studied using electron paramagnetic resonance (EPR). Minimal inhibitory concentrations of the complexes dissolved in DES and dimethyl sulfoxide (DMSO) were determined and found to be equivalent in both solvents. That is, use of reline as a solvent did not alter the functional properties of the metal complexes. Changes in the transdermal permeation of the complexes in DMSO and DES were assessed using a Franz diffusion cell. It was discovered that depending on the structure of the complex, the permeability might either increase (from 15 to 30%) or decrease (from 13 to 8%) with changes in the solvent, and this can be used to develop dosing strategies. Therapeutic eutectogels were successfully produced by impregnating SiO2 nanoparticles with the metal complex solution in DES, facilitating convenient topical application.

We prepared and studied the last unreported members of square antiprismatic lanthanide tris-acetylacetonate complexes with 1,10-phenanthroline, namely, [Ln(acac)3(phen)], formed by Nd3+ (Nd), Ho3+ (Ho) and Tm3+ (Tm) ions. An optimized synthetic technique, which allows for the preparation of single phase complexes of both light and heavy lanthanides, was proposed for the first time. For the entire [Ln(acac)3(phen)] series, structural trends arising from the increase in the covalency of Ln-O(acac) bonds and the decrease in the flexibility of the coordination geometry were revealed. In particular, a change in the crystal packing from the La and Ce complexes to those formed by Pr-Lu was confirmed. Within the Pr-Lu sub-series, an increase in the symmetry of the coordination polyhedron, along with an increase in the volume fraction of crystal voids, takes place. Complex Nd is a new representative of the scarcely studied Nd-based single-molecule magnets, SMMs. The slowdown of demagnetization in Nd is achieved under non-zero magnetic fields and proceeds via the combination of the Raman mechanism and quantum tunneling of magnetization. Supported by a thorough literature survey of Nd-based SMMs, these findings allow assuming that square antiprismatic coordination environments are effective in enhancing the SMM performance of Nd(iii) complexes.

Based on the results of initial flux-assisted exploratory synthesis in the Eu-Pt-Ni-P system, three new quaternary R6Pt30-xNi17+yP22 compounds (R = Ca, Sr, Eu) were synthesized. According to the single-crystal XRD data, they crystallize in their own structure type (I4/mmm; a = 11.4716(4) Å, c = 16.2458(7) Å, R1 = 0.0386 (Ca6Pt27.1Ni19.8P22); a = 11.5784(5) Å, c = 16.2339(10) Å, R1 = 0.0305 (Sr6Pt27.7Ni19.2P22); a = 11.5882(5) Å, c = 16.3586(9) Å, R1 = 0.0273 (Eu6Pt28.8Ni18.1P22)), closely related to the Ce3Pt23Ge11 type. For the europium-containing compound, the structure was confirmed by the Rietveld refinement of the PXRD data from the bulk sample. The structure of the compounds is a complex 3D framework of nesting polyhedra, which, according to the DFT calculations and bonding analysis, is dominated by Pt-P and Ni-P bonds. According to the calculations, all the compounds are metallic. Magnetic measurements for Eu6Pt28.8Ni18.1P22 reveal it to be a soft ferromagnet with TC of ca. 4 K. These compounds represent the first quaternary compounds in the respective systems and the first examples of phosphorus-containing compounds with structures closely related to the Ce3Pt23Ge11 type.

Seven new heterometallic 3,5-di- tert -butylbenzoate complexes with a {Co 2 Ln} metal core were synthesised and characterised by means of X-ray diffraction. Three of these complexes exhibit SMM behavior.

Five new heterometallic carboxylate complexes of the composition [Co2Li2(A)6(L)2] (L = 4-phenylpyridine, A = 2-furoate anion (1); L = 2,2'-bipyridine, A = 2-furoate anion (2), 3,5-di-tert-butylbenzoate anion (3); L = quinoline, A = 3-cyanobenzoate anion (4), 4-cyanobenzoate anion (5)) were synthesized. The structures of all compounds were determined by single-crystal X-ray diffraction. When monodentate N-donor ligands are replaced by chelating 2,2'-bipyridine, the coordination polyhedron of cobalt ions changes from a distorted tetrahedron to a distorted octahedron. Complexes 1-4 are field induced single-molecule magnets. Mechanisms of slow magnetic relaxation are discussed taking into account both experimental data and quantum chemical calculations.

A series of heterometallic carboxylate complexes [Co2Ln(NO3)(piv)6(bpy)2] (Ln = La (1), Eu (2), Gd (3); piv is pivalate-anion, bpy is 2,2′-bipyridine) was synthesized and characterized by means of single crystal as well as powder X-ray diffraction. Compounds 1 and 2 are field-induced single molecule magnets in which slow magnetic relaxation mainly attributed to the Raman and quantum tunneling of the magnetization (for 1) or Raman and direct (for 2) mechanisms which is typical for five-coordinated Co(II) ions. Compound 3 does not show single molecule magnet behavior.

Novel mononuclear complexes [M((CF3)2pz)2((CH3)2pzH)2] (M = Zn (1), CoII (2), and CuII (3)) and binuclear complexes [Cu2(mu-(CF3)pz)2((CH3)2pzH)2(OOCBut)2] (4) were prepared by different simple synthetic methods and characterized by single crystal X-ray diffraction analysis. Compounds 1 and 2 have a similar structure with a tetrahedral metal environment, unlike compound 3, in which copper is in a square-planar environment. A copper square planar environment is also found in 4. The structures of the complexes are stabilized by intermolecular (1, 2, and 4) and intramolecular (3) hydrogen bonds. 1 was additionally characterized in solution by 1H NMR. The study of thermal behavior indicated the transformation of 2 into the pyrazolate bridging polymer [Co((CH3)2pz)2]n at 330 degrees C. Magnetic susceptibility measurements in the ac-magnetic field show the presence of slow field-induced (Hdc = 2500 Oe) magnetic relaxation behavior for the Co-based complex 2.

Organic nitroxide radicals - specifically chloro-, bromo, and iodo-substituted nitronyl nitroxides - exhibit self-assembly in crystalline states through the combined action of halogen (Hal center dot center dot center dot ONO) and hydrogen (ONO & ctdot;HMe) bonds. Theoretical calculations reveal that halogen bonds primarily govern the association of these nitroxides. This halogen bonding facilitates the proximity of atoms carrying spin densities of opposite signs, thereby promoting ferromagnetic intermolecular exchange interactions. This research demonstrates, for the first time, that halogen bonding can establish channels facilitating ferromagnetic intermolecular exchange between paramagnetic centers in organic nitronyl nitroxide radicals. This breakthrough discovery expands the potential applications of halogen bonding in the supramolecular modulation of magnetic properties within high-spin clusters-a function that was previously attributed exclusively to hydrogen bonding.

Transient or time-resolved electron paramagnetic resonance spectroscopy (TR EPR) is a powerful method for studying various photogenerated paramagnetic species. The use of low-energy quanta, such as terahertz (THz) radiation, as an external stimulus in TR EPR allows the initiation of spin dynamics without generating new paramagnetic species other than those already present in the system. This spin dynamic reflects the return of the system to thermodynamic equilibrium, governed by a spin-lattice relaxation time, T1. The latter, together with a phase memory time, is of paramount importance for the practical implementation of single-molecule magnets and molecular spin qubits. In this work, we present TR EPR spectroscopy with pulsed heating by THz pulses as a versatile spectroscopic method for determining T1 in a wide range of paramagnetic systems. To define the scope of the method, we developed a numerical model based on the Liouville-von Neumann equation, with the equilibrium density matrix defined by the temperature profile of the lattice. Using experimental data obtained for [CoTp2] (cobalt(II) bis[tris(pyrazolyl)borate]) with S = 3/2, we compared the proposed method with two other commonly used techniques: alternating current (AC) magnetometry and pulsed EPR. All three methods were found to be in qualitative agreement and provided complementary information about the relaxation properties. TR EPR spectroscopy showed the orientation dependence of T1. AC magnetometry revealed the dependence of T1 on the value of the external magnetic field, which was attributed in the literature to a field-induced Raman process. Finally, pulsed EPR spectroscopy was found to be biased by strong spectral diffusion.

The development of precursors for hydrogenation processes based on heterometallic iron( iii ) complexes will provide a relevant alternative to “non-platinum” catalysts.

We report the synthesis, structural characterization, and physicochemical properties of two erbium(III) tetrakis (hexafluoroacetylacetonate) salts: the known sodium complex Na+[Er(hfac)4]- (1) and a novel compound featuring a photochromic cation, (C25H25N2O)+[Er(hfac)4]- (2), where the cation is 1-[(1 ',3 ',3 '-trimethylspiro[2H-1-benzopyran-2,2 '-indoline]-8-yl)methyl]pyridinium. Single crystal X-ray diffraction analysis reveals that complex 2 crystallizes in the monoclinic space group P21/ c, with alternating layers of magnetic anions and photochromic cations held together by ionic and van der Waals interactions. Notably, the replacement of the small Na+ cation in 1 with a bulky organic cation in 2 leads to a distortion of the [ErO8] coordination geometry from a square antiprism to a distorted dodecahedron, suppressing the single-ion magnet (SIM) behavior observed in 1. Conversely, the magnetic anion in 2 activates solid-state photochromism in the cation, which is inactive in its bromide form. This effect could be attributed to the highly polar environment provided by the [Er(hfac)4]- anion, which stabilizes the zwitterionic merocyanine form of the cation, the effect being analogous to solvatochromism. These findings demonstrate a rare and mutually responsive interaction between magnetic and photochromic sublattices in the crystalline material, offering valuable insights into the design of multifunctional hybrid systems with opto-magnetic switching capabilities.

Tetracyanidoborates of divalent lanthanides, Ln[B(CN)4]2THF (Ln = Eu (1), Yb (2)), were obtained by a salt metathesis reaction of lanthanide diiodides and ammonium tetracyanidoborate. Unlike known tetracyanidoborates of alkaline-earth metals and trivalent lanthanides, compounds 1 and 2 are 3D metal-organic frameworks (MOFs) with a cubic structure. MOF 1 demonstrates air stability and thermal stability up to 400 degrees C. At 298 K, 1 shows bright broadband photoluminescence (PL) of Eu2+ ions that peaked at 650 nm with 80% absolute quantum yield (QY). When the temperature increases from 77 to 500 K, the maximum of PL spectra of 1 exhibit a blue shift from 13900 to 16350 cm-1. Quantum chemical calculations and X-ray diffraction studies of 1 at 100 and 390 K reveal that observed PL thermochromism is accompanied by changes in the geometry of the Eu-N-C fragment and electronic structure of the [B(CN)4]- anion. Europium-containing MOF 1 exhibits slow relaxation of magnetization at temperatures up to 4 K. The magnetic relaxation dynamics of MOF 1 is dominated by an Orbach-like mechanism with an effective energetic barrier estimated as 16.7 K. Removal of THF from the pores of MOF 1 leads to the same changes in structure and luminescent behavior as heating but significantly reduces its stability in air. The singularity of structural, magnetic, and luminescent behavior, as well as extraordinary stability of europium MOF 1, are due to specifics in europium-tetracyanidoborate bonding. The reported tetracyanidoborates 1 and 2 are the porous 3D MOFs based on divalent lanthanide ions: europium and ytterbium.

Magnetically bistable compounds attract considerable attention due to their possible applications in molecular electronics and spintronics devices. Of special interest are spin-crossover (SCO) systems that can interconvert between the low-spin and high-spin states leading to switching of the magnetic properties. Synthesis and comprehensive characterization of a family of ionic ferric-dioxolene complexes [(TPA)Fe(HO-DBCat)]ClO4 (1), [(TPA)Fe(NO2-DBCat)]ClO4 (2) and [(TPA)Fe(MeOCH2-DBCat)]ClO4 (3) (TPA = tris(2-pyridylmethyl)amine; HO-DBCat = dianion of 4,6-di-tert-butyl-1,2,3-trihydroxybenzene, NO2-DBCat = dianion of 4,6-di-tert-butyl-3-nitro-1,2-dihydroxybenzene and MeOCH2-DBCat = dianion of 4,6-di-tert-butyl-3-methoxymethyl-1,2-dihydroxybenzene) are reported. Variable temperature structural, magnetic and spectral analyses revealed that compounds 1-3 undergo a thermally induced SCO in the solid state between the high-spin (S = 5/2) and low-spin (S = 1/2) states. Alternating current magnetic susceptibility measurements indicated that the nitro-substituted complex 2 shows a field supported slow magnetic relaxation in the low-spin state at 5000 Oe. Such duality of magnetic properties makes complex 2 the first ferric compound which demonstrates a complete S = 5/2 → S = 1/2 SCO with a single molecule magnet behavior (SMM, S = 1/2). Electronic structures and magnetic properties of 1, 2 and 3 were investigated with the aid of DFT and SA-CASSCF/NEVPT2 calculations.

Malonate ligands demonstrate versatility for intercalating metal complexes into layered rare-earth hydroxides (LREHs), enabling controlled tuning of coordination geometry and composition. As a proof of concept, a series of copper(II) malonate complexes with various substituents was synthesized and successfully intercalated into layered yttrium, europium, or terbium hydroxide at room temperature via anion-exchange reactions. The copper content in these hybrid materials increased in the order: butylmalonate < benzylmalonate < cyclopropanedicarboxylate < dimethylmalonate. To further expand the range of accessible metal malonate complexes, dimethyl- and benzylmalonate anions were intercalated into layered yttrium hydroxide for the first time and subsequently metalated in situ, yielding well-defined Cu2+ species within the interlayer space without disrupting the host lattice. Density functional theory (DFT) calculations provided insight into the structural arrangements of the copper complexes in the interlayer galleries. Comprehensive characterization of the resulting materials by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), IR, UV-vis, and electron paramagnetic resonance (EPR) spectroscopy confirmed both the successful formation of hybrid structures and elucidated the coordination environment of the intercalated copper species.

A series of new mononuclear square antiprismatic complexes comprising acetylacetonate (acac-), pyrazine-2-carboxylate (PyrCOO-) and 1,10-phenanthroline (phen) ligands, namely, [Ln(acac)2(PyrCOO)(phen)] (Ln is Dy-Yb, Y; 1-5, 6), was prepared and studied. These complexes are new examples of extremely scarcely studied eight-coordinated tetra-chelate complexes comprising β-diketonate and carboxylate ligands. Complexes 1, 3 and 5 exhibit pronounced slowdown of demagnetization, with corresponding pathways additionally validated by ab initio calculations. In particular, complex 1 exhibits zero-field relaxation with a Δeff/kB of 149 K, while the application of an optimal DC field (1500 Oe) enhances the Δeff/kB value to 265 K. Thus, although the quantum tunneling of magnetization (QTM) contributes to zero-field relaxation of complex 1, this complex is among the most efficient zero-field Dy-based SMMs formed by β-diketonate and/or carboxylate ligands. Moreover, the Δeff/kB value of 1 under the optimal field is the highest among the related complexes. Interestingly, the Dy-Dy magnetic interactions have a considerable effect on the SMM performance of 1, despite on the spatial (>8 Å) separation of Dy3+ ions isolated by coats of bulky diamagnetic ligands.

The reactions of oxovanadium(iv) sulfate with cyclopropane-1,1-dicarboxylic acid (H2cpdc), Bu4NOH, and lanthanide(iii) nitrates in water solutions yielded a series of bimetallic ionic compounds (Bu4N)[Ln(H2O)8][(VO)(cpdc)2(H2O)]22/3H2O (LnV2, Ln = Gd, Tb, Dy, Er, Yb, Lu), whose crystal structures are constructed from supramolecular H-bonded layers separated by Bu4N+ cations. Single-crystal X-ray diffraction (SC-XRD) was used to determine the crystal structures of GdV2, TbV2, and DyV2, and their isostructurality with ErV2, YbV2, and LuV2 was proved by powder X-ray diffraction (PXRD). According to alternating current (ac) magnetic susceptibility measurements, GdV2, DyV2, YbV2, and LuV2 exhibit field-induced slow relaxation of magnetization. The influence of the Ln3+ ion on ac magnetic behavior of compounds LnV2 was explained using quantum chemical calculations. Thermal decomposition of GdV2 in an Ar atmosphere was studied. The end product of the solid-phase thermolysis of GdV2 in air at 600 degrees C was shown to be the complex oxide GdVO4 with the admixture of V2O5.

The interaction of Co(NO3)2 center dot 6H2O and MI2CO3 (MI = Rb or Cs) with dimethylmalonic acid (H2Me2mal) leads to the formation of 3D polymeric compounds: {[Co4Rb8(Me2mal)8(H2O)8]center dot 5H2O}n (1) and {[CoCs2(Me2mal)2 (H2O)4]center dot H2O}n (2), respectively. The structures of 1 and 2 were characterized using X-ray diffraction analysis and IR spectroscopy. Each complex contains CoII atoms arranged in four vertex polyhedra. Both compounds exhibit field-induced slow magnetic relaxation. The dc-magnetic measurements and ab initio calculation results show that 1 has "easy plane" type of magnetization, where the axial parameter D of both crystallographicaly independent Co2+ ions is positive. In contrast, parameter D of 2 is negative, which corresponds to "easy axis" type. For 2 the relaxation process includes the Orbach mechanism, which corresponds to the quantum chemical calculation.

For the first time, polymeric isostructural complexes of Y3+, Dy3+, Yb3+ and diamagnetically diluted Dy3+ and Yb3+ with flexible-chain phosphoryl podand 1,3-bis(diphenylphosphoryl)-2-oxapropane (L) were synthesized and characterized by X-ray, elemental analysis, IR and NMR spectroscopy. The bridging function of the ligand L leads to the formation of a 3D framework. The AC susceptibility measurements of the Dy3+ complex with L (1) indicated the absence of slow relaxation of magnetization in magnetic fields up to 5000 Oe. The study of the AC magnetic behavior of the Yb3+ complex with L (6) showed the presence of slow magnetic relaxation in the DC field of 2500 Oe with the most probable magnetization reversal path being the combination of Raman mechanism and the direct process. The value of the effective energy barrier of magnetic relaxation Delta E/kB according to the approximation of the high temperature part of the tau(1/T) plot to the Arrhenius equation is 24 K. Diamagnetic dilution of Dy3+ and Yb3+ compounds revealed no significant impact on the slow relaxation of magnetization.