We report the synthesis, structural and magnetothermal characterization down to sub-Kelvin temperatures of the polymeric complex {Ho(α-fur)3}n (α-fur = C4H3OCOO−). The α-furoate ligands bridge Ho(III) ions into one-dimensional zigzag chains running along the crystallographic c-axis. Two slightly distinct coordination environments, denoted Ho(A) and Ho(B), arise from positional disorder of one furoate ligand. Ab initio calculations were performed to estimate the zero-field splittings of both Ho at A and B sites. Magnetic susceptibility and heat capacity measurements show that at low temperatures, the compound behaves as an assembly of antiferromagnetically coupled S* = 1/2 Ising-like chains (J*/kB ≈ −0.4 K) of Ho ions with transverse anisotropy. The low-temperature susceptibility further reveals a small concentration of chain defects. Zero-field ac susceptibility measurements evidence slow relaxation of the magnetization assigned to defect-enabled single-chain magnet (SCM) dynamics in the two chain types, with activation energies EA,SCM = 2.9(3) K and EB,SCM = 4(3) K. Below 0.4 K, a crossover to a coherent quantum tunneling of the magnetization regime, assisted by hyperfine interactions, is observed. The relaxation behavior is discussed in comparison with the related compounds {Ln(α-fur)3}n (Ln = Dy, Tb) and {Ho2Ba(α-fur)8}n, highlighting the interplay between Kramers versus non-Kramers ion character, hyperfine interactions, and magnetic exchange topology in governing the low-temperature dynamics.

Multi-lanthanide metal-organic frameworks (MOFs) offer a flexible route for designing multifunctional materials. Here we report a carborane-based isostructural series of MOFs of formula {[(NdyYb1-y)3(mCB-L)4(NO3)(DMF)x]n & centerdot;Solv}, including the homometallic Nd (y = 1) and Yb (y = 0) compounds and a mixed Nd/Yb analogue (y = 0.44). Magnetic, magnetocaloric and near-infrared (NIR) optical properties were investigated by dc/ac magnetometry, X-ray absorption spectroscopy (XAS), X-ray magnetic circular dichroism (XMCD), and photoluminescence. Nd3+ and Yb3+ yield MOFs combining slow relaxation of the magnetization (U/kB similar to 19 K), cryogenic magnetocaloric response (-Delta Sm similar to 1.6 R at 5 T, 1.8 K) and ion-centered NIR luminescence. Notably, the mixed Nd/Yb MOF further extends this multifunctionality by exhibiting dual NIR emission at 998 nm and 1060 nm arising from partial Nd -> Yb energy transfer. These results underscore carborane ligands as effective blocks for engineering multi-lanthanide frameworks, and highlight {Nd/Yb} MOFs as multifunctional materials for quantum technologies, optical communication, and cryogenic cooling.

We present the intriguing magneto-optical properties of the lanthanide complex [Tb(coum)(3)(batho)]center dot[0.7EtOH], named Tb-batho, based on coum = 3-acetyl-4-hydroxylato-coumarin and batho = bathophenanthroline ligands. Tb-batho displays visible-range luminescence with a notable quantum yield (58%) upon sensitization of the "antenna" ligands. Employing a SQUID magnetometer equipped with a magneto-optic option, we conducted comprehensive in situ measurements of light-induced magnetization changes across varied magnetic fields, temperatures, and frequencies, utilizing light wavelengths ranging from 275 to 800 nm. A reversible magnetic modulation of magnetization is observed upon toggling the light "on" and "off," particularly pronounced at 380 nm excitation, resulting in a magnetization change Delta M(off/on) = 0.376 mu(B) fu(-1) (ca. 42.6% of the magnetization) at 1.8 K and 1 kOe. Although Tb-batho exhibits field-induced single ion magnet (SIM) behavior, characterized by a thermally-activated process with an activation energy of U-eff/k(B) = 16.6 K @ 3 kOe and a slow direct process influenced by bottleneck effects, light irradiation does not noticeably alter its dynamic properties. All in all, Tb-batho emerges as a versatile multifunctional molecular material integrating SIM behavior, luminescence and light-induced magnetic switching, holding interest for diverse electronic applications, sensors, or quantum computing.

Three novel coordination polymers - [LnLNO3(o-Phen)] (Ln: Eu(iii) (1), Sm(iii) (2)) and [Eu2L3EtOH(H2O)3]1.5EtOHH2O (3) - were synthesized by reacting the respective lanthanide nitrates with the organosilane dicarboxylic acid bis(p-carboxyphenyl)diphenylsilane (H2L) with or without o-phenanthroline (o-Phen) as coligand. The o-Phen-assisted route yielded isostructural one-dimensional coordination polymers (CP) 1 and 2, incorporating both ligands and the nitrate anion. These ribbon-like chains assemble into hydrogen-bonded 2D networks that further stack into 3D architectures through non-covalent interactions. In contrast the o-Phen-free conditions produced the 3D CP 3, based solely on H2L, with ethanol and water molecules retained in the lattice. All three architectures are highly dense, with free volumes of only 2.7% (1, 2) and 11.0% (3). Photophysical studies reveal an exceptional quantum yield of 67% for Eu-based complex 1 attributed to complete ligand-to-Eu energy transfer. In contrast, the Sm-based compound 2 achieves a modest 2% quantum yield, while compound 3 reaches 8%. Magnetic measurements confirm typical Van Vleck paramagnetism for Eu3+ in 1 and 3, with spin-orbit coupling constants of Lambda = 379 and 352 cm-1, respectively. The magnetism of the Sm-based CP 2 is governed by its ground 6H5/2 and first excited 6H7/2 multiplets (Lambda = 310 cm-1), and notably displays field-induced slow magnetic relaxation. Remarkably, Eu-based CP 1 affords exfoliation by sonication into nanometric flakes that retain a high quantum yield of 57% upon deposition, opening up exciting opportunities for surface-integrated sensing, photonic, and quantum applications.

Metal-organic frameworks (MOFs) incorporating arrays of molecular spin qubits (quMOFs) offer a promising pathway toward scalable quantum computing. In this work, we introduce a novel quMOF, {[(Gd)3(mCB-L)4(NO3)(DMF)x]n·Solv}, constructed with a carborane linker and Gd(III) ions at three distinct coordination sites. We thoroughly characterize its magneto-thermal properties using dc/ac magnetometry, X-ray absorption spectroscopy, X-ray magnetic circular dichroism, and heat capacity measurements. The quantum computing potential is demonstrated through ab initio calculations and pulsed electron paramagnetic resonance on GdY-diluted analogues, revealing Tm= 0.7 μs and Rabi oscillations persisting up to 50 K. Each of the three isolated Gd(i) sites in GdY-MOFs functions as an 8-level qudit, accessible via X-band transitions. Notably, the triple-site Gd3 quMOF provides an unprecedented qudit with d = (2S + 1)3 = 512 states, capable of encoding up to 9 qubits, marking a significant advance in the scalability of molecular-based quantum computing systems.

One-dimensional (1D) antiferromagnetic chains are fascinating because of their exotic quantum phenomena. However, isolating large-spin S chains remains challenging as even minimal interchain interaction J ' tends to drive unwanted long-range ordering. Here, we report on the synthesis, crystal structure, magnetism, optical, and electronic properties of two isostructural metal-organic frameworks (MOFs), [M-2(mCB-L)(2)(mu(2)-H2O)(2)(DMF)(4)](n)solv (M = Co(ii) (mCB-Co) or Ni(ii) (mCB-Ni)), which feature water-bridged Co (S = 3/2) or Ni (S = 1) spin chains that are effectively separated by bulky carborane linkers (1,7-di(4-carboxyphenyl)-1,7-dicarba-closo-dodecaborane, mCBLH(2)). The temperature-dependent susceptibility reveals strong antiferromagnetic interactions with significant intrachain coupling, J(Co)/k(B) = -4.65 K (mCB-Co) and J(Ni)/k(B) = -23.36 K (mCB-Ni), yet confirm the absence of long-range order down to 0.3 K due to negligible interchain interactions, as corroborated by specific heat data. This indicates extremely small J ', with J '/J < 4.7 x 10(-4) (3.7 x 10(-5)) for Co (Ni) MOFs, making these new materials nearly ideal 1D antiferromagnets. Additionally, optical band gaps were estimated via the Kubelka-Munk method, yielding an increase from 3.83 eV for mCB-Co to 4.20 eV for mCB-Ni, showcasing tunable electronic properties across the two MOFs.

The controlled deposition of organized molecular materials on technologically relevant substrates is crucial for the development of innovative magneto-optical devices. In this work, we report the growth of lanthanoid-based 2D metal-organic frameworks (MOFs) with formula unit [Ln(MeCOO)(PhCOO)2] (Ln = Dy, Tb) on Si(100) wafers functionalized by silanization. The thickness, morphology and composition of the grown material was assessed using a combination of ellipsometry, contact angle measurements, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The on-surface grown terbium 2D MOFs exhibit green luminescence, like the bulk. Furthermore, chemisorbed Dy and Tb 2D MOFs retain a significant magnetic moment, as demonstrated by X-ray magnetic circular dichroism (XMCD) measurements conducted at the M4,5 edge of the two lanthanoids. Our work paves the way for the preparation of magneto-optical devices and organized arrays of single-molecule magnets (SMMs) and qubits on surfaces for high-density information storage and quantum computing applications.

The spin frustration and other magnetic properties of the "cartwheel" heptanuclear cluster [FeIII 7O3(O2C t Bu)9(Me-dea)3(H2O)3] (Me-deaH2 = N-methyldiethanolamine) have been previously investigated; we present here a Mossbauer spectroscopic study and sub-Kelvin magnetization and ac susceptibility measurements which enable a complete magnetic picture of this frustrated cluster. 57Fe Mossbauer spectra above 150 K showed three doublets in a 1:3:3 ratio, which could be assigned by their respective quadrupole splittings to the central Fe(1) and the peripheral Fe(2) and Fe(3). The field dependence of the corresponding magnetic sextets at 3 K showed that the spins on the central Fe(1) and the three peripheral Fe(2) sites with O5N coordination are oriented mutually coparallel, while these are antiparallel to the spins on the peripheral Fe(3) sites with O6 coordination, resulting in an overall S = 5/2 ground state. This provides experimental confirmation of the previously proposed spin ground state structure. Upon cooling to sub-Kelvin temperatures, a crossover to spin blocking with T B approximate to 0.21 K could be observed. This single-molecule magnet behavior had been expected but had not been observable with a conventional SQUID. The anisotropy barrier, of 3-fold symmetry, can be described in terms of the parameter D/k B = -0.47 K and a fourth-order perturbation; the latter enables thermally activated quantum tunneling through the excited sublevel m z = +/- 3/2, with an activation barrier of U/k B = 1.9 K.

Gd complexes have been studied as magnetic coolants due to their large magneto-caloric effect. In this work we present a Gd 2D metal-organic framework (MOF) of formula [Gd(MeCOO)(PhCOO)2] (1). We characterize the magnetic properties of 1, showing that it displays slow relaxation of the magnetization by ac susceptibility, and single-ion magnetic anisotropy using high-field EPR. By heat capacity and magnetization vs. field at various temperatures we determine the magnetic entropy change of compound 1. We then grow 1 on functionalized silicon, and show that the surface-deposited 2D MOF 1Si can be used as an on-surface magnetic cryogenic coolant.

Abstract In this work, we review recent progress achieved in the use of chemical solution deposition (CSD) based on fluorinated metalorganic precursors to grow superconducting REBa2Cu3O7 (REBCO) films and coated conductors (CCs). We examine, first of all, the advances in optimizing the steps related to the solutions preparation, deposition and pyrolysis based on novel low-fluorine metalorganic solutions. We show that a new type of multifunctional colloidal solutions including preformed nanoparticles (NPs), can be used to introduce artificial pinning centers (APCs). We analyze how to disentangle the complex physico-chemical transformations occurring during the pyrolysis with the purpose of maximizing the film thicknesses. Understanding the nucleation and growth mechanisms is shown to be critical to achieve a fine tuning of the final microstructure, either using the spontaneous segregation or the colloidal solution approaches, and make industrially scalable this process. Advanced nanostructural studies have deeply modified our understanding of the defect structure and its genealogy. It is remarkable the key role played by the high concentration of randomly distributed and oriented BaMO3 (M = Zr, Hf) NPs which enhance the concentration of APCs, such as stacking faults and the associated partial dislocations. Correlating the defect structure with the critical current density Jc (H,T,θ) allows to reach a tight control of the vortex pinning properties and to devise a general scheme of the vortex pinning landscape in the whole H–T phase diagram. We also refer to the outstanding recent achievements in enhancing the vortex pinning strength by shifting the carrier concentration in REBCO films towards the overdoped state, where the pinning energy is maximum and so, record values of critical current densities are achieved. This confirms the performance competitiveness of nanocomposite CCs prepared through the CSD route. We conclude with a short summary of the progress in scaling the CC manufacturing using fluorinated solutions.

Multivariate metal-organic frameworks (MOFs) containing multiple lanthanide ions present a compelling avenue for developing versatile materials with tailored properties. In this work, we synthesized "self-refrigerated" multifunctional carborane-based MOFs of formula unit {[(GdLn)3(mCB-L)4(NO3)(DMF)x]nSolv} strategically combining Gd3+ ions, known for their ability to achieve large magnetocaloric effects (MCE), with various lanthanides (Ln = Dy, Tb, Eu, Tb/Eu) intended to act as Single Molecule Magnet (SMM) or/and luminescent units. The intricate magnetic, thermal, and optical properties of these multivariate Ln-MOFs were unraveled through a comprehensive characterization employing dc and ac magnetometry, X-ray Absorption Spectroscopy (XAS), X-ray Magnetic Circular Dichroism (XMCD), and luminescence measurements. Element-selective XAS-XMCD technique proved instrumental in elucidating the magnetic properties of the individual lanthanides, and their contribution to the macroscopic properties of the MOFs. We demonstrate that Gd1.5Ln1.5 (Ln = Tb, Dy) MOFs exhibit multifunctionality, incorporating MCE, field-induced magnetic relaxation dominated by the anisotropic ion, and green emission for Ln = Tb. Conversely, Gd1.5Ln1.5 (Ln = Eu, Eu/Tb) MOFs display MCE, field-induced SMM behavior associated with Gd, and red/yellow luminescent emission for Ln = Eu and Eu/Tb substitutions, respectively. Our findings significantly contribute to our understanding of "complex magnetic molecular materials" and set a pathway for the design of multifunctional multi-lanthanide MOFs endowed with tailored properties for various technological applications. "Self-refrigerated" multifunctional MOFs combine Gd for optimal magnetocalorics with other lanthanides (Dy, Tb, Eu) as single-molecule magnets and/or luminescent units, offering exciting possibilities for information storage and processing.

The synthesis, structure and magnetothermal properties of three new lanthanide 1D polymeric complexes, {[Ln2Ba(α-fur)8(H2O)4]}n for Ln = Nd (1), Er (2) and {[Ho2Ba(α-fur)8(H2O)4]⋅2H2O}n (3), based on carboxylic α-fur = C4H3OCOO ligands is reported. The α-furoate ligands consolidate zigzag chains formed by Ln2 dimers separated by Ba ions. Ab initio calculations, in combination with the fit of experimental static magnetization and heat capacity, predict the magnetic ground state, energy levels and magnetic interactions in these heteronuclear nanomagnets. Nd2Ba (1) presents two different coordination sites for Nd, with an orthorhombic magnetic ground state. Nd ions are coupled along the chain through a weak antiferromagnetic (AF) interaction J″/kB = −0.08 K. Er(III) ions in Er2Ba (2) present a highly axial ground state, forming magnetic dimers with an interaction of J′/kB = −8.6 K, while interdimer coupling along the chain is J″/kB = −0.28 K. The Ho2Ba (3) complex consists of a highly anisotropic quasi-doublet with a ΔHo/kB = 0.7 K gap. Non-Kramers Ho ions form magnetic dimers within the Ho2Ba cluster, coupled by an AF intradimer interaction J′/kB = −2.5 K. The three complexes exhibit in-field slow relaxation of the magnetization: 1 relaxes through an Orbach process at high temperatures [Ueff/kB = 60(1) K] evolving to quantum tunneling below 3 K [τQT = 0.05(1) s]; 2 exhibits a rapid Orbach-like process [τ0 = 8(6)⋅10–8 s and Ueff/kB = 10(2) K] and 3 shows a direct process [τ = 0.4(1) s].

In this paper we report the microwave assisted synthesis and characterization of a family of Na-Ln coordination polymers (CPs) of formula [NaDy2(MeCOO)2(SALOH)5(chpH)2] (1Ln, Ln=Eu, Gd, Tb, Dy, Ho, Y). The Na+ cations isolate Ln2 units in a one-dimensional polymer. By changing the lanthanoid ions, we attain Single Molecule Magnet properties (1Dy), luminescent properties (1Eu, 1Tb, 1Ho), a diamagnetic material (1Y) and a material that presents magnetocaloric effect (1Gd). We report the microwave assisted synthesis and characterization of a family of Na-Ln coordination polymers of formula [NaDy2(MeCOO)2(SALOH)5(chpH)2] (1Ln, Ln=Eu, Gd, Tb, Dy, Ho, Y). By changing the lanthanoid ions, we attain Single Molecule Magnet properties (1Dy), luminescent properties (1Eu, 1Tb, 1Ho), a diamagnetic material (1Y) and a material that presents magnetocaloric effect (1Gd). image

Organic Chemistry is widely recognized as a challenging subject, with the design of syntheses and retrosyntheses identified as particularly difficult tasks. Inspired by the success of artificial neural networks in machine learning, we propose a framework that leverages similar principles to enhance the teaching and learning of organic synthesis. In this paper, we introduce a novel teaching tool, the "Synthetic Map", that attempts to visually recreate an expert's mental map and conceptual understanding of organic synthesis built over years of experience. The educational benefits of the Synthetic Map were evaluated through its implementation in an Organic Chemistry course of a Pharmacy degree over two years. The new tool promoted students' learning by providing a mental organizer fostering a deeper understanding of the subject and empowering students to design and execute effective synthetic strategies.

We present the synthesis and magneto-thermal properties of carborane-based lanthanide metal-organic frameworks (MOFs) with the formula {[(Ln)3(mCB-L)4(NO3)(DMF)n]Solv}, where Ln = Dy or Tb, characterized by dc and ac susceptibility, X-ray absorption spectroscopy (XAS), X-ray magnetic circular dichroism (XMCD) and heat capacity measurements. The MOF structure is formed by polymeric 1D chains of Ln ions with three different coordination environments (Ln1, Ln2, Ln3) running along the b-axis, linked by carborane-based linkers thus to provide a 3D structure. Static magnetic measurements reveal that these MOFs behave at low temperature as a system of S* = 1/2 Ising spins, weakly interacting ferromagnetically along the 1D polymeric chain (J*/kB = +0.45 K (+0.5 K) interaction constant estimated for Dy-MOF (Tb-MOF)) and coupled to Ln ions in adjacent chains through dipolar antiferromagnetic interactions. The Dy MOF exhibits slow relaxation of magnetization through a thermally activated process, transitioning to quantum tunneling of the magnetization at low temperatures, while both compounds exhibit field-induced relaxation through a very slow, direct process. The maximum magnetic entropy changes (-Delta Smaxm) for an applied magnetic field change of 2-0 T are 5.71 J kg-1 K-1 and 4.78 J kg-1 K-1, for Dy and Tb MOFs, respectively, while the magnetocaloric effect (MCE) peak for both occurs at T similar to 1.6 K, approximately double that for the Gd counterpart. We report the synthesis, structure and magneto-thermal properties of two isostructural carborane-based MOFs, {[(Ln)3(mCB-L)4(NO3)(DMF)n]Solv} with Ln = Dy or Tb, characterized by combining dc and ac magnetometry, XAS-XMCD and heat capacity measurements.

Multi‐metallic multivariate (MTV) rare earth (RE) metal−organic frameworks (MOFs) are of interest for the development of multifunctional materials, however examples with more than three RE cations are rare and obstructed by compositional segregation during synthesis. Herein, this work demonstrates the synthesis of a multi‐metallic MTV RE MOF incorporating two, four, six, or eight different RE ions with different sizes and in nearly equimolar amounts and no compositional segregation. The MOFs are formed by a combination of RE cations (La, Ce, Eu, Gd, Tb, Dy, Y, and Yb) and a 1,7‐di(4‐carboxyphenyl)‐1,7‐dicarba‐ closo ‐dodecaborane ( m CB‐L) linker. The steric bulkiness and acidity of m CB‐L is crucial for the incorporation of different size RE ions into the MOF structure. Demonstration of the incorporation of all RE cations is performed via compositional and structural characterization. The more complex MTV MOF, including all eight RE ions ( m CB‐8RE), are also characterized using optical, thermal, and magnetic techniques. Element‐selective X‐ray absorption spectroscopy and X‐ray Magnetic Circular Dichroism measurements allow us to characterize spectroscopically each of the eight RE ions and determine their magnetic moments. This work paves the way for the investigation of MTV MOFs with the possibility to combine RE ions à la carte for diverse applications.

We report the deposition of monolayers and multilayers of {Cr-10(OMe)(20)(O2CCMe3)(10)} wheels, hereafter {Cr-10}, onto Au(111) and Cu(111) single-crystal substrates, and their characterization combining scanning tunneling microscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, X-ray natural linear dichroism, and X-ray magnetic circular dichroism (XMCD). {Cr-10} in bulk shows axial magnetic anisotropy and a cluster total spin S = 9 ground state, stemming from an interaction scheme of two semi-crowns containing four Cr3+ ions interacting ferromagnetically, separated by two Cr3+ antiferromagnetically coupled. The one-monolayer (1ML) samples of {Cr-10} sublimated on Ag(111) and Cu(111) show slightly different applied magnetic field dependence of XMCD signal. The field-dependence of the magnetization evolves from a lower curve for the 1ML {Cr-10} samples to a curve resembling the bulk one as the number of layers is increased, as shown in a 14ML sample. Monte Carlo simulations allow rationalizing the magnetization curves of the 1ML samples in terms of a reduction of the cluster ground-state total spin, S = 3 or S = 6, as a consequence of variations in the intra-wheel coupling interactions induced by the on-surface deposition. The sensitivity of the magnetic configuration of {Cr-10} to minor distortions of the intramolecular conformation might be exploited to control magnetism by external stimuli for applications.

We present the synthesis, through a simple, microwave-assisted method, of lanthanoid-based 2D metal-organic frameworks (MOFs) of general formula [LnxLn'1-x(MeCOO)(PhCOO)2], including homonuclear compounds (x = 1), LnEu, Tb, and heterometallic compounds, [TbEu]. The crystalline material is formed by neutral nanosheets held together by van der Waals interactions, which can be easily exfoliated by sonication. Photoluminescent emission in the visible range was observed for all of the synthesized 2D MOF compounds via excitation of the ligand, showing benzoates are efficient antenna ligands. Efficient energy transfer from Tb → Eu was observed in the heterometallic [TbEu] compounds, which could potentially perform as luminescent thermometers. Inks containing nanosheets of 2D MOFs exfoliated in solution were prepared, and luminescent prints of Tb and Eu 2D MOFs on paper were made to show the possible application for anticounterfeiting. Frequency-dependent ac susceptibility results show the occurrence of slow magnetic relaxation in [TbEu] compounds through direct relaxation mechanisms, affected by bottleneck effect. A slowing down of the relaxation time is observed as the Eu/Tb ratio increases.

We report a simple method for large area surface functionalization. A proof of concept is given by grafting the complexes [Ln2(SYML)3(H2O)] on functionalized Si(100) and using a combination of techniques, including GIXRD, XMCD and luminescence.