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The imidophosphorane ligand, [NPtBu3]− (tBu=tert‐butyl), enables isolation of a pseudo‐tetrahedral, tetravalent praseodymium complex, [Pr4+(NPtBu3)4] (1‐Pr), which is characterized by a suite of physical characterization methods including single‐crystal X‐ray diffraction, electron paramagnetic resonance, and L3‐edge X‐ray near‐edge spectroscopies. Variable‐temperature direct‐current magnetic susceptibility data, supported by multiconfigurational quantum chemical calculations, demonstrate that the electronic structure diverges from the isoelectronic Ce3+ analogue, driven by increased crystal field. The four‐coordinate environment around Pr4+ in 1‐Pr, which is unparalleled in reported extended solid systems, provides a unique opportunity to study the interplay between crystal field splitting and spin‐orbit coupling in a molecular tetravalent lanthanide within a pseudo‐tetrahedral coordination geometry. [ABSTRACT FROM AUTHOR]

The dinitrogen (N2) chemistry of lanthanides remains less developed compared to the d‐block metals and lanthanide‐promoted N2 functionalization chemistry in well‐defined lanthanide complexes remains elusive. Here we report the synthesis and characterization (SQUID, EPR, DFT, X‐Ray) of the siloxide supported heterobimetallic (Tm/K) complexes [{KTm(OSi(OtBu)3)3}2(μ‐η2 : η2‐N2)] (1) and [K3{Tm(OSi(OtBu)3)3}2(μ‐η2 : η2‐N2)] (2). Complex 2 provides a rare example of a metal complex of the triply reduced N23− radical. The structure of 2 differs from the few previously reported N23− complexes as it presents two Tm and three K cations binding the N23− radical, facilitating N2 functionalization. Notably, the K3Tm2‐bound N23− moiety reacts with excess H+ to form NH4Cl in 18 % yield, and with MeOTf at room temperature to yield the dimethyl hydrazido complex [K2{Tm(OSi(OtBu)3)3}2(μ‐(CH3)NN(CH3))] (3). Protonolysis of 3 yields MeHN−NMeH ⋅ 2HCl in 18 % yield. [ABSTRACT FROM AUTHOR]

Here we report on the Magneto‐Chiral Dichroism (MChD) detected through visible and near‐infrared light absorption of two enantiomeric pairs of ErIII and TmIII chiral complexes featuring a propeller‐like molecular structure. The magnetic properties show typical features of isolated paramagnetic ions associated with 4I15/2 and 3H6 ground state terms. MChD spectroscopy shows high gMChD dissymmetry factors of ca. 0.12 T−1 and 0.05 T−1 (T=4.0 K and B=1.0 T) for ErIII and TmIII, respectively, associated with the magnetic‐dipole allowed 4I13/2 ← 4I15/2 and 3H5 ← 3H6 transitions. MChD signals of the two complexes were detected up to room temperature and under magnetic fields up to 5.0 T. For the first time, the MChD results are discussed in the context of the Richardson theory of lanthanide optical activity and provide clear indications on the strongest MChD‐active electronic transitions of lanthanide complexes. [ABSTRACT FROM AUTHOR]

Large dissymmetry factor of the circularly polarized luminescence (gCPL) was observed in ligand and coordination tuned chiral tetrakis europium (Eu(III)) complexes with ammonium cations. The gCPL value was estimated to be −1.54, which is the largest among chiral luminescent molecules. Through photophysical measurements, single crystal X‐ray structural analyses and quantum chemical calculations, changes in the geometric and electronic structures were observed for a series of chiral tetrakis Eu(III) complexes which enhanced the gCPL value. The emission quantum yield and photosensitized energy transfer efficiencies of chiral Eu(III) complexes with ammonium cations were also larger than those of chiral Eu(III) complex with Cs+. Based on the systematic modifications and analyses for chiral tetrakis Eu(III) complex, effect of the ammonium cation on enhanced CPL brightness is reported. [ABSTRACT FROM AUTHOR]

Lanthanide nanoparticle (LnNP) scintillators exhibit huge potential in achieving radionuclide‐activated luminescence (radioluminescence, RL). However, their structure–activity relationship remains largely unexplored. Herein, progressive optimization of LnNP scintillators is presented to unveil their structure‐dependent RL property and enhance their RL output efficiency. Benefiting from the favorable host matrix and the luminescence‐protective effect of core–shell engineering, NaGdF4 : 15 %Eu@NaLuF4 nanoparticle scintillators with tailored structures emerged as the top candidates. Living imaging experiments based on optimal LnNP scintillators validated the feasibility of laser‐free continuous RL activated by clinical radiopharmaceuticals for tumor multiplex visualization. This research provides unprecedented insights into the rational design of LnNP scintillators, which would enable efficient energy conversion from Cerenkov luminescence, γ‐radiation, and β‐electrons into visible photon signals, thus establishing a robust nanotechnology‐aided approach for tumor‐directed radio‐phototheranostics. [ABSTRACT FROM AUTHOR]

Lanthanoid carboxylates were synthesized and in situ self‐assembled to illustrate temperature‐driven evolution in chromaticity. Evolution in structure (crystallinity), composition, luminosity, and chromaticity were investigated revealing the coupled role of divergence in order/structure (spatial organization), and composition in tuning observed color. Loss of crystallinity or increase in residual carbon leads to decrease in luminosity even with increase in hue. Comparing Ho and Er congeners shows that the density of accessible transition states relates to shifts in low and high wavelength components of color. This work demonstrates that, just as interface dipoles can lead to change in semiconductor band gap, structure and composition can analogously alter observed color. [ABSTRACT FROM AUTHOR]

Herein, we present the first report on the synthesis of rare‐earth complexes featuring a 9,10‐diborataanthracene ligand. This 14‐π‐electron ligand is highly reductive and was previously used in small‐molecule activation. Salt elimination reactions between dipotassium 9,10‐diethyl‐9,10‐diborataanthracene [K2(DEDBA)] and [LnIII(η8‐CotTIPS)(BH4)(thf)x] (CotTIPS=1,4‐(iPr3Si)2C8H6) in a 1 : 1 ratio yielded heteroleptic sandwich complexes [K(η8‐CotTIPS)LnIII(η6‐DEDBA)] (Ln=Y, Dy, Er). These compounds form Lewis‐base‐free one‐dimensional coordination polymers when crystallised from toluene. In contrast, reaction of [K2(DEDBA)] and [LnIII(η8‐CotTIPS)(BH4)(thf)x] in a 1 : 2 ratio led to the formation of heteroleptic triple‐decker complexes [(η8‐CotTIPS)LnIII(μ‐η6:η6‐DEDBA)LnIII(η8‐CotTIPS)] (Ln=Y, Dy, Er). Notably, these are not only the first lanthanide triple‐decker compounds featuring a six‐membered ring as a deck but also the first trivalent lanthanide triple‐decker featuring a heterocycle in the coordination sphere. Magnetic investigations reveal that [K(η8‐CotTIPS)LnIII(η6‐DEDBA)] (Ln=Dy, Er) and [(η8‐CotTIPS)ErIII(μ‐η6:η6‐DEDBA)ErIII(η8‐CotTIPS)] exhibit Single‐Molecule Magnet (SMM) behaviour. In the case of [(η8‐CotTIPS)LnIII(μ‐η6:η6‐DEDBA)LnIII(η8‐CotTIPS)] (Ln=Dy, Er), the introduction of a second near lanthanide ion results in strong antiferromagnetic interactions, allowing the enhancement of the magnetic characteristic of the system, compared to the quasi isolated counterpart. This research renews the overlooked coordination chemistry of the DBA ligand and expands it to encompass rare‐earth elements. [ABSTRACT FROM AUTHOR]

A series of isostructural Ln3O2(CN3) (Ln=La, Eu, Gd, Tb, Ho, Yb) oxoguanidinates was synthesized under high‐pressure (25–54 GPa) high‐temperature (2000–3000 K) conditions in laser‐heated diamond anvil cells. The crystal structure of this novel class of compounds was determined via synchrotron single‐crystal X‐ray diffraction (SCXRD) as well as corroborated by X‐ray absorption near edge structure (XANES) measurements and density functional theory (DFT) calculations. The Ln3O2(CN3) solids are composed of the hitherto unknown CN35− guanidinate anion—deprotonated guanidine. Changes in unit cell volumes and compressibility of Ln3O2(CN3) (Ln=La, Eu, Gd, Tb, Ho, Yb) compounds are found to be dictated by the lanthanide contraction phenomenon. Decompression experiments show that Ln3O2(CN3) compounds are recoverable to ambient conditions. The stabilization of the CN35− guanidinate anion at ambient conditions provides new opportunities in inorganic and organic synthetic chemistry. [ABSTRACT FROM AUTHOR]

Remote temperature probing at the cryogenic range is of utmost importance for the advancement of future quantum technologies. Despite the notable achievements in luminescent thermometers, accurately measuring temperatures below 10 K remains a challenging endeavor. In this study, we propose a novel magneto‐optical thermometric approach based on the magnetic‐circular dichroism (MCD) technique, which offers unprecedented capabilities for meticulous temperature variation analysis at cryogenic temperatures. The inherent temperature sensitivity of the MCD C‐term, in conjunction with both positive and negative signals, enables highly sensitive magneto‐optical temperature probing. Additionally, a groundbreaking relative thermal sensitivity value of 95.3 % K−1 at 2.54 K can be achieved using a mononuclear lanthanide complex, [[Ho(acac)3(phen)], in the presence of a 0.25 T applied magnetic field and using a combination of multiparametric thermal read‐out with multiple regression. These results unequivocally demonstrate the viability and effectiveness of our methodology for cryogenic temperature sensing. [ABSTRACT FROM AUTHOR]

The surface chemistry of nanoparticles is a key step on the pathway from particle design towards applications in biologically relevant environments. Here, a bilayer‐based strategy for the surface modification of hydrophobic nanoparticles is introduced that leads to excellent colloidal stability in aqueous environments and good protection against disintegration, while permitting surface functionalization via simple carbodiimide chemistry. We have demonstrated the excellent potential of this strategy using upconversion nanoparticles (UCNPs), initially coated with oleate and therefore dispersible only in organic solvents. The hydrophobic oleate capping is maintained and a bilayer is formed upon addition of excess oleate. The bilayer approach renders protection towards luminescence loss by water quenching, while the incorporation of additional molecules containing amino functions yields colloidal stability and facilitates the introduction of functionality. The biological relevance of the approach was confirmed with the use of two model dyes, a photosensitizer and a nitric oxide (NO) probe that, when attached to the surface of the UCNPs, retained their functionality to produce singlet oxygen and detect intracellular NO, respectively. We present a simple and fast strategy to protect and functionalize inorganic nanoparticles in biological media, which is important for controlled surface engineering of nanosized materials for theranostic applications. [ABSTRACT FROM AUTHOR]

Macroscopic compass‐like magnetic alignment at low magnetic fields is natural for ferromagnetic materials but is seldomly observed in paramagnetic materials. Herein, we report a "paramagnetic compass" that magnetically aligns under ∼mT fields based on the single‐crystalline framework constructed by lanthanide ions and organic ligands (Ln‐MOF). The magnetic alignment is attributed to the Ln‐MOF's strong macroscopic anisotropy, where the highly‐ordered structure allows the Ln‐ions' molecular anisotropy to be summed according to the crystal symmetry. In tetragonal Ln‐MOFs, the alignment is either parallel or perpendicular to the field depending on the easiest axis of the molecular anisotropy. Reversible switching between the two alignments is realized upon the removal and re‐adsorption of solvent molecules filled in the framework. When the crystal symmetry is lowered in monoclinic Ln‐MOFs, the alignments become even inclined (47°‐66°) to the field. These fascinating properties of Ln‐MOFs would encourage further explorations of framework materials containing paramagnetic centers. [ABSTRACT FROM AUTHOR]

Anisotropy is an intrinsic property of crystalline materials. However, the photoluminescence anisotropy in eutectic crystals of organometallic complexes has remained unexplored. Herein, the eutectic of polynuclear lanthanide complexes and Ag clusters was prepared, and the crystal shows significant photoluminescence anisotropy. The polarization anisotropy of emission δ and degree of excitation polarization P are 2.62 and 0.53, respectively. The rare excitation polarization properties have been proved to be related to the regular arrangement of electric transition dipole moments of luminescent molecules in the crystal. Our design provides a reference for developing new photoluminescence anisotropy materials and expanding their applications. [ABSTRACT FROM AUTHOR]

Halide double perovskites [A2MIMIIIX6] are an important class of materials that have garnered substantial interest as non‐toxic alternatives to conventional lead iodide perovskites for optoelectronic applications. While numerous studies have examined chloride and bromide double perovskites, reports of iodide double perovskites are rare, and their definitive structural characterization has not been reported. Predictive models have aided us here in the synthesis and characterization of five iodide double perovskites of general formula Cs2NaLnI6 (Ln=Ce, Nd, Gd, Tb, Dy). The complete crystal structures, structural phase transitions, optical, photoluminescent, and magnetic properties of these compounds are reported. [ABSTRACT FROM AUTHOR]

Certain f‐block elements—the lanthanides—have biological relevance in the context of methylotrophic bacteria. The respective strains incorporate these 4 f elements into the active site of one of their key metabolic enzymes, a lanthanide‐dependent methanol dehydrogenase. In this study, we investigated whether actinides, the radioactive 5 f elements, can replace the essential 4 f elements in lanthanide‐dependent bacterial metabolism. Growth studies with Methylacidiphilum fumariolicum SolV and the Methylobacterium extorquens AM1 ΔmxaF mutant demonstrate that americium and curium support growth in the absence of lanthanides. Moreover, strain SolV favors these actinides over late lanthanides when presented with a mixture of equal amounts of lanthanides together with americium and curium. Our combined in vivo and in vitro results establish that methylotrophic bacteria can utilize actinides instead of lanthanides to sustain their one‐carbon metabolism if they possess the correct size and a +III oxidation state. [ABSTRACT FROM AUTHOR]

Upconverting nanoparticles (UCNPs) are promising candidates for photon-driven reactions, including light-triggered drug delivery, photodynamic therapy, and photocatalysis. Herein, we investigate the NIR-to-UV/visible emission of sub-15 nm alkaline-earth rare-earth fluoride UCNPs (M1-x Lnx F2+x, MLnF) with a CaF2 shell. We synthesize 8 alkaline-earth host materials doped with Yb3+ and Tm3+ , with alkaline-earth (M) spanning Ca, Sr, and Ba, MgSr, CaSr, CaBa, SrBa, and CaSrBa. We explore UCNP composition, size, and lanthanide doping-dependent emission, focusing on upconversion quantum yield (UCQY) and UV emission. UCQY values of 2.46 % at 250 W cm-2 are achieved with 14.5 nm SrLuF@CaF2 particles, with 7.3 % of total emission in the UV. In 10.9 nm SrYbF:1 %Tm3+ @CaF2 particles, UV emission increased to 9.9 % with UCQY at 1.14 %. We demonstrate dye degradation under NIR illumination using SrYbF:1 %Tm3+ @CaF2 , highlighting the efficiency of these UCNPs and their ability to trigger photoprocesses.

Solvation of [(CNT)Ln(η8‐COT)] (Ln=La, Ce, Nd, Tb, Er; CNT=cyclononatetraenyl, i.e. C9H9−; COT=cyclooctatetraendiid, i.e. C8H82−) complexes with tetrahydrofuran (THF) gives rise to neutral [(η4‐CNT)Ln(thf)2(η8‐COT)] (Ln=La, Ce) and ionic [Ln(thf)x(η8‐COT)][CNT] (x=4 (Ce, Nd, Tb), 3 (Er)) species in a solid‐to‐solid transformation. Due to the severe distortion of the ligand sphere upon solvation, these species act as switchable luminophores and single‐molecule magnets. The desolvation of the coordinated solvents can be triggered by applying a dynamic vacuum, as well as a temperature gradient stimulus. Raman spectroscopic investigations revealed fast and fully reversible solvation and desolvation processes. Moreover, we also show that a Nd:YAG laser can induce the necessary temperature gradient for a self‐sufficient switching process of the Ce(III) analogue in a spatially resolved manner. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln) tetraisobutylaluminates constitute key components in commercial 1,3‐diene polymerization catalysts, and likewise are the homogeneous rare‐earth‐metal catalysts of prime industrial importance. Discrete divalent rare‐earth‐metal complexes [Ln(AliBu4)2] (Ln=Sm, Eu, Yb) reported here display the first structurally characterized homoleptic metal tetraisobutylaluminates. Treatment of [Ln(AliBu4)2] with C2Cl6 gives access to SmII/SmIII mixed‐valence cluster [Sm6Cl8(AliBu4)6] and the YbII cluster [Yb4Cl4(AliBu4)4], respectively. Reaction with B(C6F5)3 leads to hydride abstraction and formation of arene‐coordinated hydroborates such as [Sm{HB(C6F5)3}2(toluene)2]. Complexes [Ln(AliBu4)2] engage in single‐component isoprene polymerization, affording high cis‐1,4 polyisoprenes with narrow molecular weight distributions. Binary [Yb(AliBu4)2]/[HNPhMe2][B(C6F5)4] fabricates polyisoprene in a perfectly living manner. The catalytically active species are scrutinized by NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Herein, we report on the preparation of liquid dimeric lanthanide(III)‐containing compounds. Starting from the design of dimeric solids, we demonstrate that by tuning of anion and cation structures we can lower the melting points below room temperature, whilst maintaining the dimeric structure. Magnetic measurements could establish the spin‐spin interactions of the neighboring lanthanide(III) ions in the liquid state at low temperatures, and matched the interactions of the analogous crystalline solid compounds. [ABSTRACT FROM AUTHOR]

Lanthanide‐doped metal–organic frameworks (Ln‐MOFs) have versatile luminescence properties, however it is challenging to achieve lanthanide‐based upconversion luminescence in these materials. Here, 1,3,5‐benzenetricarboxylic acid (BTC) and trivalent Yb3+ ions were used to generate crystalline Yb‐BTC MOF 1D‐microrods with upconversion luminescence under near infrared excitation via cooperative luminescence. Subsequently, the Yb‐BTC MOFs were doped with a variety of different lanthanides to evaluate the potential for Yb3+‐based upconversion and energy transfer. Yb‐BTC MOFs doped with Er3+, Ho3+, Tb3+, and Eu3+ ions exhibit both the cooperative luminescence from Yb3+ and the characteristic emission bands of these ions under 980 nm irradiation. In contrast, only the 497 nm upconversion emission band from Yb3+ is observed in the MOFs doped with Tm3+, Pr3+, Sm3+, and Dy3+. The effects of different dopants on the efficiency of cooperative luminescence were established and will provide guidance for the exploitation of Ln‐MOFs exhibiting upconversion. [ABSTRACT FROM AUTHOR]

Nylon‐6 is selectively depolymerized to the parent monomer ϵ‐caprolactam by the readily accessible and commercially available lanthanide trisamido catalysts Ln(N(TMS)2)3 (Ln=lanthanide). The depolymerization process is solvent‐free, near quantitative, highly selective, and operates at the lowest Nylon‐6 to ϵ‐caprolactam depolymerization temperature reported to date. The catalytic activity of the different lanthanide trisamides scales with the Ln3+ ionic radius, and this process is effective with post‐consumer Nylon‐6 as well as with Nylon‐6+polyethylene, polypropylene or polyethylene terephthalate mixtures. Experimental kinetic data and theoretical (DFT) mechanistic analyses suggest initial deprotonation of a Nylon terminal amido N−H bond, which covalently binds the catalyst to the polymer, followed by a chain‐end back‐biting process in which ϵ‐caprolactam units are sequentially extruded from the chain end. [ABSTRACT FROM AUTHOR]

Novel chiral Er complexes based on both enantiomers of extended iPrPyBox (2,6‐Bis[4‐isopropyl‐4,5‐dihydrooxazol‐2‐yl)]pyridine) show strong near‐infrared circularly polarized luminescence (CPL) within the 1400 to 1600 nm spectral region under 450 nm irradiation. CPL activity in this region, despite being particularly rare, would open the way to potential applications in the domain, e.g., of fiber‐optic telecommunications and free‐space long‐distance optical communications employing circularly polarized light. Moreover, the long wavelength excitation is advantageous for applications in the field of (circularly polarized) microscopy and bioimaging. [ABSTRACT FROM AUTHOR]

Biosensing approaches that combine small, engineered antibodies (nanobodies) with nanoparticles are often complicated. Here, we show that nanobodies with different C‐terminal tags can be efficiently attached to a range of the most widely used biocompatible semiconductor quantum dots (QDs). Direct implementation into simplified assay formats was demonstrated by designing a rapid and wash‐free mix‐and‐measure immunoassay for the epidermal growth factor receptor (EGFR). Terbium complex (Tb)‐labeled hexahistidine‐tagged nanobodies were specifically displaced from QD surfaces via EGFR‐nanobody binding, leading to an EGFR concentration‐dependent decrease of the Tb‐to‐QD Förster resonance energy transfer (FRET) signal. The detection limit of 80±20 pM (16±4 ng mL−1) was 3‐fold lower than the clinical cut‐off concentration for soluble EGFR and up to 10‐fold lower compared to conventional sandwich FRET assays that required a pair of different nanobodies. [ABSTRACT FROM AUTHOR]

The ability to construct complex molecular architectures with precise control is critical for realizing molecule‐based materials and functions. Using the assembly of a 60‐metal complex of ErIII with histidine as an example, we demonstrate the rational assembly of otherwise synthetically elusive polynuclear lanthanide hydroxide clusters directed by the combined set of I− and CO32− as templates. We succeeded in the stepwise transformation starting from Er12 to Er60 by way of two key intermediates Er34 and Er48. The Er12, Er34, and Er48 core motifs represent respectively 1/6, 1/2, and 3/4 of the complete sodalite cage of Er60. This work, representing a rare example of rationally constructing high‐nuclearity lanthanide clusters guided by judiciously chosen templates, is expected to stimulate more future efforts for the controllable synthesis of complex molecular or supramolecular architectures with unprecedented structural sophistication and possibly useful properties. [ABSTRACT FROM AUTHOR]

Photon upconversion (UC) in molecular species remains a highly sought‐after property with vast potential applications in many fields. Until now, a few reports on molecular upconverters are limited to demonstrating upconversion. The low UC quantum yields (QY) and nuclearities hindered the application capabilities for molecular upconverters. To overcome these limitations, we report the use of a molecular cluster‐aggregate (MCA) containing 20 lanthanide ions to target YbIII‐TbIII‐based cooperative UC. Upconversion quantum yield value of 1.04×10−4 %, among the highest value observed for a molecular cooperative UC, was attained for the {Gd11Tb2Yb7} composition. Substitution of GdIII ions for EuIII centers opens a YbIII→TbIII→EuIII energy‐transfer pathway, allowing the first proof‐of‐concept of potential application for molecular UC. This report on upconversion‐based luminescence thermometry in a molecular species endorses further development of upconversion properties of nanoscale MCAs. [ABSTRACT FROM AUTHOR]

The fast Raman relaxation process via a virtual energy level has become a puzzle for how to chemically engineer single‐molecule magnets (SMMs) with better performance. Here, we use the trifluoromethyl group to systematically substitute the methyl groups in the axial position of the parent bis‐butoxide pentapyridyl dysprosium(III) SMM. The resulting complexes—[Dy(OLA)2py5][BPh4] (LA=CH(CF3)2−1, CH2CF3−2, CMe2CF3−3)—show progressively enhanced TBhys (@100 Oe s−1) from 17 K (for 3), 20 K (for 2) to 23 K (for 1). By experimentally identifying the varied under barrier relaxation energy in the 5–500 cm−1 regime, we are able to identify that the C−F bond related vibration energy of the axial ligand ranging from 200 to 350 cm−1 is the key variant for this improvement. Thus, this finding not only reveals a correlation between the structure and the Raman process but also provides a paradigm for how to apply the vibronic barrier model to analyze multi‐phonon relaxation processes in lanthanide SMMs. [ABSTRACT FROM AUTHOR]

The reduction of UVI uranyl halides or amides with simple LnII or UIII salts forms highly symmetric, linear, oxo-bridged trinuclear UV /LnIII /UV , LnIII /UIV /LnIII , and UIV /UIV /UIV complexes or linear LnIII /UV polymers depending on the stoichiometry and solvent. The reactions can be tuned to give the products of one- or two-electron uranyl reduction. The reactivity and magnetism of these compounds are discussed in the context of using a series of strongly oxo-coupled homo- and heterometallic poly(f-block) chains to better understand fundamental electronic structure in the f-block.

The assembly of nanoscale polyoxometalate (POM) clusters has been dominated by the highly reduced icosahedral {Mo132} "browns" and the toroidal {Mo154} "blues" which are 45 % and 18 % reduced, respectively. We hypothesised that there is space for a greater diversity of structures in this immediate reduction zone. Here we show it is possible to make highly reduced mix‐valence POMs by presenting new classes of polyoxomolybdates: [MoV52MoVI12H26O200]42− {Mo64} and [MoV40MoVI30H30O215]20− {Mo70}, 81 % and 57 % reduced, respectively. The {Mo64} cluster archetype has a super‐cube structure and is composed of five different types of building blocks, each arranged in overlayed Archimedean or Platonic polyhedra. The {Mo70} cluster comprises five tripodal {MoV6} and five tetrahedral {MoV2MoVI2} building blocks alternatively linked to form a loop with a pentagonal star topology. We also show how the reaction yielding the {Mo64} super‐cube can be used in the enrichment of lanthanides which exploit the differences in selectivity in the self‐assembly of the polyoxometalates. [ABSTRACT FROM AUTHOR]

Advancing our understanding of the minor actinides (Am, Cm) versus lanthanides is key for developing advanced nuclear-fuel cycles. Herein, we describe the preparation of (NBu4 )Am[S2 P((t) Bu2 C12 H6 )]4 and two isomorphous lanthanide complexes, namely one with a similar ionic radius (i.e., Nd(III) ) and an isoelectronic one (Eu(III) ). The results include the first measurement of an Am-S bond length, with a mean value of 2.921(9) Å, by single-crystal X-ray diffraction. Comparison with the Eu(III) and Nd(III) complexes revealed subtle electronic differences between the complexes of Am(III) and the lanthanides.

Building blocks with multiple components are promising for the synthesis of complex molecular assemblies, but are rarely available. Herein, we report a modification procedure for a multi‐component building block [Ln3Ti(HSA)6(SA)4(H2O)]− ({Ln3Ti‐SA}, H2SA=salicylic acid, Ln=Eu/Gd) to form new building blocks {Ln3Tix‐MSA} (H2MSA=5‐methoxysalicylic acid, x=1, 2, 3) by constructing [Ti(MSA)3]2− units. The obtained {Ln3Tix‐MSA} can further assemble into a chiral Ln22Ti14 ring with the formulae [Eu22Ti14(MSA)48(HMSA)22(CH3COO)4(H2O)10(iPrOH)] and [Gd22Ti14(MSA)46(HMSA)26(CH3COO)4(H2O)8]. Parallel experiments without Ti4+ result in linear Ln chains. Detailed analysis shows that the [Ti(MSA)4]4− unit makes the originally variable Ln chains become available building blocks and the modified [Ti(MSA)3]2− further triggers interesting chiral‐sorting behavior. Finally, the electronic adsorption and magneto‐optic responses of these molecular rings are investigated. [ABSTRACT FROM AUTHOR]

Reduction of [SmIII(COT1,4‐SiiPr3)(BH4)(thf)] (COT1,4‐SiiPr3=1,4‐(iPr3Si)3C8H6) with KC8 resulted in [SmIII/II/III(COT1,4‐SiiPr3)4], the first example of a homoleptic lanthanide quadruple‐decker. As indicated by an analysis of the bond metrics in the solid‐state, the inner Sm ion is present in the divalent oxidation state, while the outer ones are trivalent. This observation could be confirmed by quantum chemical calculations. Mechanistic studies revealed not only insight into possible formation pathways of [SmIII/II/III(COT1,4‐SiiPr3)4] but also resulted in the transformation to other mixed metal sandwich complexes with unique structural properties. These are the 1D‐polymeric chain structured [KSmIII(COT1,4‐SiiPr3)]n and the hexametallic species [(tol)K(COT1,4‐SiiPr3)SmII(COT1,4‐SiiPr3)K]2 which were initially envisioned as possible building blocks as part of different retrosynthetically guided pathways that we developed. [ABSTRACT FROM AUTHOR]

Herein we report unprecedented location‐dependent, size‐selective binding to designed lanthanide (Ln3+) sites within miniature protein coiled coil scaffolds. Not only do these engineered sites display unusual Ln3+ selectivity for moderately large Ln3+ ions (Nd to Tb), for the first time we demonstrate that selectivity can be location‐dependent and can be programmed into the sequence. A 1 nm linear translation of the binding site towards the N‐terminus can convert a selective site into a highly promiscuous one. An X‐ray crystal structure, the first of a lanthanide binding site within a coiled coil to be reported, coupled with CD studies, reveal the existence of an optimal radius that likely stems from the structural constraints of the coiled coil scaffold. To the best of our knowledge this is the first report of location‐dependent metal selectivity within a coiled coil scaffold, as well as the first report of location‐dependent Ln3+ selectivity within a protein. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks (MOFs) heterostructures with domain‐controlled emissive colors have shown great potential for achieving high‐throughput sensing, anti‐counterfeit and information security. Here, a strategy based on steric‐hindrance effect is proposed to construct lateral lanthanide‐MOFs (Ln‐MOFs) epitaxial heterostructures, where the channel‐directed guest molecules are introduced to rebalance in‐plane and out‐of‐plane growth rates of the Ln‐MOFs microrods and eventually generate lateral MOF epitaxial heterostructures with controllable aspect ratios. A library of lateral Ln‐MOFs heterostructures are acquired through a stepwise epitaxial growth procedure, from which rational modulation of each domain with specific lanthanide doping species allows for definition of photonic barcodes in a two‐dimensional (2D) domain with remarkably enlarged encoding capacity. The results provide molecular‐level insight into the use of modulators in governing crystallite morphology for spatially assembling multifunctional heterostructures. [ABSTRACT FROM AUTHOR]

Guided by a second‐sphere interaction strategy, we fabricated a Tb(III)‐based metal—organic framework (MMCF‐4) for turn‐on sensing of methyl amine with ultra‐low detection limit and high turn‐on efficiency. MMCF‐4 features lanthanide nodes shielded in a nonacoordinate geometry along with secondary coordination spheres that are densely populated with H‐bond interacting sites. Nonradiative routes were inhibited by binding‐induced rigidification of the ligand on the second coordination sphere, resulting in luminescence amplification. Such remote interacting mechanism involved in the turn‐on sensing event was confirmed by single‐crystal X‐ray diffraction and molecular dynamic simulation studies. The design of both primary and secondary coordination spheres of Tb(III) enabled the first turn‐on sensing of organic amines in aqueous conditions. Our work suggests a promising strategy for high‐performance turn‐on sensing for Ln‐MOFs and luminous materials driven by other metal chromophores. [ABSTRACT FROM AUTHOR]

Multitopic organic linkers can provide a means to organize metal cluster nodes in a regular three-dimensional array. Herein, we show that isonicotinic acid N-oxide (HINO) serves as the linker in the formation of a metal-organic framework featuring Dy2 single-molecule magnets as nodes. Importantly, guest solvent exchange induces a reversible single-crystal to single-crystal transformation between the phases Dy2(INO)4(NO3)2⋅2 solvent (solvent=DMF (Dy2-DMF), CH3CN (Dy2-CH3CN)), thereby switching the effective magnetic relaxation barrier (determined by ac magnetic susceptibility measurements) between a negligible value for Dy2-DMF and 76 cm(-1) for Dy2-CH3CN. Ab initio calculations indicate that this difference arises not from a significant change in the intrinsic relaxation barrier of the Dy2 nodes, but rather from a slowing of the relaxation rate of incoherent quantum tunneling of the magnetization by two orders of magnitude.

Polyoxometalates (POMs, metals=VV, NbV, TaV, MoVI, WVI) are molecular metal oxides that can be isolated without capping ligands. The high negative charge of polyoxoniobates (PONb) provides strong interactions with heterocations, advantageous for electrostatic assembly of modular materials. In four single‐crystal X‐ray structures, we demonstrate that carbonate combined with the very reactive decaniobate [Nb10O28]6− reassembles into a new decaniobate, [Nb10O25(CO3)6]12−, featuring three carbonate‐ligated Nb‐polyhedra. These Nb‐sites can be replaced by heterometals (lanthanides), and the tridentate carbonate can serve as an anchor point to build niobate‐frameworks. Small‐angle X‐ray scattering and two additional X‐ray structures reveal that the reaction pathway proceeds through a Nb24‐PONb intermediate, and the obtained PONb (with or without carbonate) is counterion, temperature, and solvent‐dependent (water or mixed water‐methanol). This provides an uncommon level of control for PONb chemistry. [ABSTRACT FROM AUTHOR]

We report the microwave assisted synthesis of a bidimensional (2D) MOF of formula [Dy(MeCOO)(PhCOO)2]n (1) and its magnetically diluted analogue [La0.9Dy0.1(MeCOO)(PhCOO)2] (1 d). 1 is a 2D material with single‐ion‐magnet (SIM) behaviour and 1 d is a multifunctional, magnetic and luminescent 2D material. 1 can be exfoliated into stable nanosheets by sonication. [ABSTRACT FROM AUTHOR]

We present the η3‐coordination of the 2‐phosphaethynthiolate anion in the complex (PN)2La(SCP) (2) [PN=N‐(2‐(diisopropylphosphanyl)‐4‐methylphenyl)‐2,4,6‐trimethylanilide)]. Structural comparison with dinuclear thiocyanate‐bridged (PN)2La(μ‐1,3‐SCN)2La(PN)2 (3) and azide‐bridged (PN)2La(μ‐1,3‐N3)2La(PN)2 (4) complexes indicates that the [SCP]− coordination mode is mainly governed by electronic, rather than steric factors. Quantum mechanical investigations reveal large contributions of the antibonding π*‐orbital of the [SCP]− ligand to the LUMO of complex 2, rendering it the ideal precursor for the first functionalization of the [SCP]− anion. Complex 2 was therefore reacted with CAACs which induced a selective rearrangement of the [SCP]− ligand to form the first CAAC stabilized group 15–group 16 fulminate‐type complexes (PN)2La{SPC(RCAAC)} (5 a,b, R=Ad, Me). A detailed reaction mechanism for the SCP‐to‐SPC isomerization is proposed based on DFT calculations. [ABSTRACT FROM AUTHOR]

Divalent lanthanide organometallics are well‐known highly reducing compounds usually used for single electron transfer reactivity and small molecule activation. Thus, their very reactive nature prevented for many years the study of their physical properties, such as magnetic studies on a reliable basis. Herein, the access to rare organometallic sandwich compounds of TmII with the cyclooctatetraenyl (Cot) ligand impacts on the use of divalent organolanthanide compounds as an additional strategy for the design of performing Single Molecule Magnets (SMM). The first divalent thulium sandwich complex with f13 configuration behaving as a single‐molecule magnet in absence of DC field is highlighted. [ABSTRACT FROM AUTHOR]

Counterfeit goods represent a major problem to companies, governments, and customers, affecting the global economy. In order to protect the authenticity of products and documents, optical anti‐counterfeit technologies have widely been employed via the use of discrete molecular species, extended metal–organic frameworks (MOFs), and nanoparticles. Herein, for the first time we demonstrate the potential use of molecular cluster‐aggregates (MCA) as optical barcodes via composition and energy transfer control. The tuneable optical properties for the [Ln20(chp)30(CO3)12(NO3)6(H2O)6], where chp−=deprotonated 6‐chloro‐2‐pyridinol, allow the fine control of the emission colour output, resulting in high‐security level optical labelling with a precise read‐out. Moreover, a unique tri‐doped composition of GdIII, TbIII, and EuIII led to MCAs with white‐light emission. The presented methodology is a unique approach to probe the effect of composition control on the luminescent properties of nanosized molecular material. [ABSTRACT FROM AUTHOR]

Covalent Organic Frameworks (COFs), an emerging class of crystalline porous materials, are a new type of support for grafting lanthanide ions (Ln3+), which can be employed as ratiometric luminescent thermometers. In this work we have shown that COFs co‐grafted with lanthanide ions (Eu3+, Tb3+) and Cu2+ (or potentially other d‐metals) can synchronously be employed both as a nanothermometer and catalyst during a chemical reaction. The performance of the thermometer could be tuned by changing the grafted d‐metal and solvent environment. As a proof of principle, the Glaser coupling reaction was investigated. We show that temperature can be precisely measured during the course of the catalytic reaction using luminescence thermometry. This concept could be potentially easily extended to other catalytic reactions by grafting other d‐metal ions on the Ln@COF platform. [ABSTRACT FROM AUTHOR]

Single‐molecule magnets (SMMs) are at the forefront of new technological advances in quantum information processing and spintronics. Despite the recent impressive breakthroughs in extending the magnetic blocking temperatures beyond liquid‐nitrogen temperatures, significant challenges await in terms of integrating and addressing such compounds in devices. With this ultimate goal in mind, the design of multifunctional SMMs not only allows to imbue molecules of interest with specific properties that would allow for in situ monitoring of the SMM operation in real time, but can also provide critical insights into our understanding of the magnetic behaviour. In this Review, we highlight how magnetism and luminescence can be harmoniously combined within single molecules to achieve these objectives. The key design principles to attain the simultaneous combination of photoluminescence and slow relaxation of the magnetization are discussed, along with an outlook on how such molecules could be beneficial for emerging next‐generation spintronics devices. [ABSTRACT FROM AUTHOR]

Temperature sensors play a significant role in biology, chemistry, and engineering, especially those that can work accurately in a noninvasive manner. We adopted a photoinduced post‐synthetic copolymerization strategy to realize a membranous ratiometric luminescent thermometer based on the emissions of two lanthanide ions. This novel mixed‐lanthanide polyMOF membrane exhibits not only the integrity and temperature sensing behaviour of the Ln‐MOF powder but also excellent mechanical properties, such as flexibility, elasticity, and processability. Moreover, the polyMOF membrane shows remarkable stability under harsh conditions, including high humidity, strong acid and alkali (pH 0–14), which allowed the mapping of temperature distributions in extreme circumstances. This work highlights a simple strategy for polyMOF membrane formation and pushes forward the further practical application of Ln‐MOF‐based luminescent thermometers in various fields and conditions. [ABSTRACT FROM AUTHOR]

Upconverting nanoparticles (UCNPs) are promising candidates for photon‐driven reactions, including light‐triggered drug delivery, photodynamic therapy, and photocatalysis. Herein, we investigate the NIR‐to‐UV/visible emission of sub‐15 nm alkaline‐earth rare‐earth fluoride UCNPs (M1−xLnxF2+x, MLnF) with a CaF2 shell. We synthesize 8 alkaline‐earth host materials doped with Yb3+ and Tm3+, with alkaline‐earth (M) spanning Ca, Sr, and Ba, MgSr, CaSr, CaBa, SrBa, and CaSrBa. We explore UCNP composition, size, and lanthanide doping‐dependent emission, focusing on upconversion quantum yield (UCQY) and UV emission. UCQY values of 2.46 % at 250 W cm−2 are achieved with 14.5 nm SrLuF@CaF2 particles, with 7.3 % of total emission in the UV. In 10.9 nm SrYbF:1 %Tm3+@CaF2 particles, UV emission increased to 9.9 % with UCQY at 1.14 %. We demonstrate dye degradation under NIR illumination using SrYbF:1 %Tm3+@CaF2, highlighting the efficiency of these UCNPs and their ability to trigger photoprocesses. [ABSTRACT FROM AUTHOR]

The ability to incorporate functional metal ions (Mn+) into metal–organic coordination complexes adds remarkable flexibility in the synthesis of multifunctional organic–inorganic hybrid materials with tailorable electronic, optical, and magnetic properties. We report the cation‐exchanged synthesis of a diverse range of hollow Mn+‐phytate (PA) micropolyhedra via the use of hollow Co2+‐PA polyhedral networks as templates at room temperature. The attributes of the incoming Mn+, namely Lewis acidity and ionic radius, control the exchange of the parent Co2+ ions and the degree of morphological deformation of the resulting hollow micropolyhedra. New functions can be obtained for both completely and partially exchanged products, as supported by the observation of Ln3+ (Ln3+=Tb3+, Eu3+, and Sm3+) luminescence from as‐prepared hollow Ln3+‐PA micropolyhedra after surface modification with dipicolinic acid as an antenna. Moreover, Fe3+‐ and Mn2+‐PA polyhedral complexes were employed as magnetic contrast agents. [ABSTRACT FROM AUTHOR]

Micro/nanoscale photonic barcodes based on multicolor luminescent segmented heterojunctions hold potential for applications in information security. However, such multicolor heterojunctions reported thus far are exclusively based on static luminescent signals, thus restricting their application in advanced confidential information protection. Reported here is a strategy to design responsive photonic barcodes with heterobimetallic (Tb3+/Eu3+) metal—organic framework multicolor heterostructures. The spatial colors could be precisely controlled by thermally manipulating the energy‐transfer process between the two lanthanides, thus achieving responsive covert photonic barcodes. Also demonstrated is that spatially resolved responsive barcodes with multi‐responsive features could be created in a single heterostructure. These findings offer unique opportunities to purposely design highly integrated responsive microstructures and smart devices toward advanced anti‐counterfeiting applications. [ABSTRACT FROM AUTHOR]

Postsynthetic installation of lanthanide cubanes into a metallosupramolecular framework via a single‐crystal‐to‐single‐crystal (SCSC) transformation is presented. Soaking single crystals of K6[Rh4Zn4O(l‐cys)12] (K6[1]; l‐H2cys=l‐cysteine) in a water/ethanol solution containing Ln(OAc)3 (Ln3+=lanthanide ion) results in the exchange of K+ by Ln3+ with retention of the single crystallinity, producing Ln2[1] (2Ln) and Ln0.33[Ln4(OH)4(OAc)3(H2O)7][1] (3Ln) for early and late lanthanides, respectively. While the Ln3+ ions in 2Ln exist as disordered aqua species, those in 3Ln form ordered hydroxide‐bridged cubane clusters that connect [1]6− anions in a 3D metal‐organic framework through coordination bonds with carboxylate groups. This study shows the utility of an anionic metallosupramolecular framework with carboxylate groups for the creation of a series of metal cubanes that have great potential for various applications, such as magnetic materials and heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

The coordination of actinides and lanthanides, as well as strontium and cesium with graphdiyne (GDY) was studied experimentally and theoretically. On the basis of experimental results and/or theoretical calculations, it was suggested that Th4+, Pu4+, Am3+, Cm3+, and Cs+ exist in single‐ion states on the special triangular structure of GDY with various coordination patterns, wherein GDY itself is deformed in different ways. Both experiment and theoretical calculations strongly indicate that UO22+, La3+, Eu3+, Tm3+ and Sr2+ are not adsorbed by GDY at all. The distinguished adsorption behaviors of GDY afford an important strategy for highly selective separation of actinides and lanthanides, Th4+ and UO22+, and Cs+ and Sr2+, in the nuclear fuel cycle. Also, the present work sheds light on an approach to explore the unique functions and physicochemical properties of actinides in single‐ion states. [ABSTRACT FROM AUTHOR]

Lanthanide triflates have been used to incorporate NdIII and SmIII ions into the 2.2.2‐cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3 complexes (Ln=Nd, Sm; OTf=SO3CF3) react with crypt in THF to form the THF‐soluble complexes [LnIII(crypt)(OTf)2][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII‐in‐crypt complexes using KC8 in THF forms the neutral LnII‐in‐crypt triflate complexes [LnII(crypt)(OTf)2]. DFT calculations on [NdII(crypt)]2+], the first NdII cryptand complex, assign a 4f4 electron configuration to this ion. [ABSTRACT FROM AUTHOR]

Complexes of trivalent lanthanides (Ln) are known to possess strong magnetic anisotropy, which enables them to be efficient single‐molecule magnets. High‐level ab initio calculations are reported for [LnO] (where Ln is terbium (Tb), dysprosium (Dy), or holmium (Ho)), which show that divalent lanthanides can exhibit equally strong magnetic anisotropy and magnetization blocking barriers. In particular, detailed calculations predict a multilevel magnetization blocking barrier exceeding 3000 K for a [DyO] complex deposited on a hexagonal boron nitride (h‐BN) surface, bringing the expected performance of single‐molecule magnets to a qualitatively new level compared to the current state‐of‐the art complexes. [ABSTRACT FROM AUTHOR]

Herein we report the development of a turn‐on lanthanide luminescent probe for time‐gated detection of nitroreductases (NTRs) in live bacteria. The probe is activated through NTR‐induced formation of the sensitizing carbostyril antenna and resulting energy transfer to the lanthanide center. This novel NTR‐responsive trigger is virtually non‐fluorescent in its inactivated form and features a large signal increase upon activation. We show that the probe is capable of selectively sensing NTR in lysates as well as in live bacteria of the ESKAPE family which are clinically highly relevant multiresistant pathogens responsible for the majority of hospital infections. The results suggest that our probe could be used to develop diagnostic tools for bacterial infections. [ABSTRACT FROM AUTHOR]