Giant Hollow Heterometallic Polyoxoniobates with Sodalite‐Type Lanthanide–Tungsten–Oxide Cages: Discrete Nanoclusters and Extended Frameworks

The first series of niobium–tungsten–lanthanide (Nb‐W‐Ln) heterometallic polyoxometalates {Ln₁₂W₁₂O₃₆(H₂O)₂₄(Nb₆O₁₉)₁₂} (Ln=Y, La, Sm, Eu, Yb) have been obtained, which are comprised of giant cluster‐in‐cluster‐like ({Ln₁₂W₁₂}‐in‐{Nb₇₂}) structures built from 12 hexaniobate {Nb₆O₁₉} clusters gathered together by a rare 24‐nuclearity sodalite‐type heterometal–oxide cage {Ln₁₂W₁₂O₃₆(H₂O)₂₄}. The Nb‐W‐Ln clusters present the largest multi‐metal polyoxoniobates and a series of rare high‐nuclearity 4d‐5d‐4f multicomponent clusters. Furthermore, the giant Nb‐W‐Ln clusters may be isolated as discrete inorganic alkali salts and can be used as building blocks to form high‐dimensional inorganic–organic hybrid frameworks.     

Cation‐Directed Dimeric versus Tetrameric Assemblies of Lanthanide‐Stabilized Dilacunary Keggin Tungstogermanates

Reaction of mid‐ to late lanthanide ions with GeO₂ and Na₂WO₄ in NaOAc buffer results in a library of [Ln₂(GeW₁₀O₃₈)]^6? clusters ( Ln₂ ), which consist of dilacunary Keggin fragments stabilized by the insertion of 4f atoms in the vacant sites and show the ability to undergo cation‐directed self‐assembly processes. In the presence of Na⁺, two β‐ Ln₂ subunits assemble by means of Ln‐O(WO₅)‐Ln bridges to form the chiral [Ln₄(H₂O)₆(β‐GeW₁₀O₃₈)₂]^12? dimeric anions (ββ‐ Ln₄ , Ln=Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). When Cs⁺ is present, two Ln₄ ‐like dimers further assemble into the [{Ln₄(H₂O)₅(GeW₁₀O₃₈)₂}₂]^24? species ( Ln₈ , Ln=Ho, Er, Tm, Yb, Lu). Two types of tetramers coexist in the solid state: One shows a full ββ‐ Ln₈ architecture, whereas the other one is a mixed αβ‐ Ln₈ assembly in which each β‐subunit is linked to its corresponding α‐ Ln₂ derivative. Regardless of differences in isomeric forms and the relative arrangement of Ln₂ subunits, all anions display virtually identical {Ln₄} cores as a common structural feature. A combination of ESI mass spectrometry and ¹⁸³W NMR spectroscopy experiments indicates that Ln₈ tetramers fragment into Ln₄ dimers upon dissolution, which undergo partial dissociation into Ln₂ monomers and slow dimer/monomer equilibration. This is most likely followed by β‐to‐α isomerization of Ln₂ clusters with consequent reassembly, as indicated by isolation of three additional αα‐ Ln₄ derivatives. Magnetic and photoluminescence properties in the Na ‐ββ‐ Ln₄ series are also discussed.     

High Nuclearity Antimonato‐Polyoxovanadate Cluster {V15Sb6O42} as a Synthon for the Solvothermal in situ Generation of α‐ and β‐{V14Sb8O42} Isomers

New heteroatom polyoxovanadates (POVs) were synthesized by applying a water‐soluble high‐nuclearity cluster as new synthon. The [V₁₅Sb₆O₄₂]^6? cluster shell exhibiting D₃ symmetry was in situ transformed into completely different cluster shells, namely, the α‐[V₁₄Sb₈O₄₂]^4? isomer with D_2d and the β‐[V₁₄Sb₈O₄₂]^4? isomer with D_2h symmetry. The solvothermal reaction of {Ni(en)₃}₃[V₁₅Sb₆O₄₂(H₂O)_x] ? 15 H₂O (x=0 or 1; en=ethylenediamine) in water led to the crystallization of [{Ni(en)₂}₂V₁₄Sb₈O₄₂] ? 5.5 H₂O containing the β‐isomer. The addition of [Ni(phen)₃](ClO₄)₂ ? 0.5 H₂O (phen=1,10‐phenanthroline) to the reaction slurry gave the new compound {Ni(phen)₃}₂[V₁₄Sb₈O₄₂] ? phen ? 12 H₂O with the α‐isomer. Both transformation reactions are complex due the change of symmetry, the chemical composition, and rearrangement of the VO₅ square pyramids and Sb₂O₅ handle‐like moieties.     

Assembly of Framework‐Isomeric 4 d–4 f Heterometallic Metal–Organic Frameworks with Neutral/Anionic Micropores and Guest‐Tuned Luminescence Properties

Framework‐isomeric three‐dimensional (3D) Cd–Ln heterometallic metal–organic frameworks (HMOFs), {[Ln₂(ODA)₆Cd₃(H₂O)₆] ? 6 H₂O}_n (Ln=Gd ( 1 a ) and Tb ( 1 b ), ODA=oxydiacetic acid) and {[Cd(H₂O)₆] ? [Ln₂(ODA)₆Cd₂] ? H₂O}_n (Ln=Gd ( 2 a ), Tb ( 2 b )), with neutral and anionic pores, respectively, were designed based on a lanthanide metalloligand strategy and synthesized by using a stepwise assembly and a hydrothermal method. Luminescence studies revealed that 1 b and 2 b can act as luminescent metal–organic frameworks and their light‐emitting properties can be modulated by small guest molecules and the manganese counterion, respectively.     

A series of high-nuclear planar equilateral triangle-shaped {Ln6(μ3-OH)6} cluster encapsulated polyoxoniobates with frequency dependent magnetic property

The integration of lanthanide (Ln) ions and polyoxoniobates (PONbs) is challenging, and the known Ln-substituted PONbs are still scarce. This work introduces high-nuclear iso-Ln-oxo clusters into the PONb system. The first series of high-nuclear Ln-oxo clusters encapsulated heterometallic polyoxoniobates H₉[Na(H₂O)₄][Cu(en)₂]₁₀{Ln₆(μ₃-OH)₆(SiNb₁₈O₅₄)₃}·18H₂O (1-Ln, en = ethylenediamine, Ln = Dy, Gd, Tb, Ho, Er, Tm, Yb, Lu) based on flower-like {Ln₆(μ₃-OH)₆(SiNb₁₈O₅₄)₃} ({Ln₆Si₃Nb₅₄}) clusters have been successfully synthesized via one-pot hydrothermal synthesis strategy. The flower-like polyoxoanion {Ln₆Si₃Nb₅₄} is consisted of three heteropolyoxoniobate {SiNb₁₈O₅₄} clusters and one unique planar equilateral triangle-shaped {Ln₆(μ₃-OH)₆} cluster, which presents the highest nuclear iso-Ln-oxo cluster in PONb chemistry. In {Ln₆(μ₃-OH)₆} cluster, each pair of μ₃-OH groups link three Dy³⁺ ions to form a small approximate equilateral triangle-shaped {Dy₃(OH)₂} cluster. Furthermore, the three {Dy₃(OH)₂} clusters comprise a bigger approximate equilateral triangle-shaped {Dy₆(μ₃-OH)₆} cluster. The reported hexanuclear {Ln₆} cluster skeletons are mostly octahedral, however, such equilateral triangle-shaped skeleton of the hexanuclear Ln-oxo cluster is first observed. The 1-Dy exhibits good water vapor adsorption capacity and ferromagnetic properties.     

A 3D Hybrid Praseodymium–Antimony–Oxochloride Compound: Single‐Crystal‐to‐Single‐Crystal Transformation and Photocatalytic Properties

A 3D organic–inorganic hybrid compound, (2‐MepyH)₃ [{Fe(1,10‐phen)₃}₃][{Pr₄Sb₁₂O₁₈(OH) Cl_11.5}(TDC)_4.5({Pr₄Sb₁₂O₁₈(OH)Cl_9.5} Cl)] ? 3 (2‐Mepy) ? 28 H₂O ( 1 ; 2‐Mepy=2‐methylpyridine, 1,10‐phen=1,10‐phenanthroline, H₂TDC=thiophene‐2,5‐dicarboxylic acid), was hydrothermally synthesized and structurally characterized. Unusually, two kinds of high‐nuclearity clusters, namely [(Pr₄Sb₁₂O₁₈ (OH)Cl₁₁)(COO)₅]^5? and [(Pr₄Sb₁₂O₁₈ (OH)Cl₉)Cl(COO)₅]^4?, coexist in the structure of compound 1 ; two of the latter clusters are doubly bridged by two μ₂‐Cl^? moieties to form a new centrosymmetric dimeric cluster. An unprecedented spontaneous and reversible single‐crystal‐to‐single‐crystal transformation was observed, which simultaneously involved a notable organic‐ligand movement between the metal ions and an alteration of the bridging ion in the dimeric cluster, induced by guest‐release/re‐adsorption, thereby giving rise to the interconversion between compound 1 and the compound (2‐MepyH)₃[{Fe(1,10‐phen)₃}₃][{Pr₄Sb₁₂O₁₈(OH)Cl_11.5}(TDC)₄({Pr₄Sb₁₂O₁₈Cl_10.5(TDC)_0.5(H₂O)_1.5}O_0.5)] ? 25 H₂O ( 1′ ). The mechanism of this transformation has also been discussed in great detail. Photocatalytic H₂‐evolution activity was observed for compound 1′ under UV light with Pt as a co‐catalyst and MeOH as a sacrificial electron donor.     

Configurational Isomerism in Polyoxovanadates

A water‐soluble derivative of the polyoxovanadate {V₁₅E₆O₄₂} (E=semimetal) archetype enables the study of cluster shell rearrangements driven by supramolecular interactions. A reaction unique to E=Sb, induced exclusively by ligand metathesis in peripheral [Ni(ethylenediamine)₃]²⁺ counterions, results in the formation of the metastable α₁* configurational isomer of the {V₁₄Sb₈O₄₂} cluster type. Contrary to all other polyoxovanadate shell architectures, this isomer comprises an inward‐oriented vanadyl group and is ca. 50 and 12 kJ mol^?1 higher in energy than the previously isolated α and β isomers, respectively. We discuss this unexpected reaction in light of supramolecular Sb?O???V and Sb?O???Sb contacts manifested in {V₁₄Sb₈O₄₂}₂ dimers detected in the solid state. ESI MS experiments confirm the stability of these dimers also in solution and in the gas phase. DFT calculations indicate that other, as of yet elusive isomers of {V₁₄Sb₈}, might be accessible as well.     

Large Hexadecametallic {MnIII–LnIII} Wheels: Synthesis,Structural, Magnetic,and Theoretical Characterization

The synthesis, gas sorption studies, magnetic properties, and theoretical studies of new molecular wheels of core type {Mn^III₈Ln^III₈} (Ln=Dy, Ho, Er, Y and Yb), using the ligand mdeaH₂, in the presence of ortho‐toluic or benzoic acid are reported. From the seven wheels studied the {Mn₈Dy₈} and {Mn₈Y₈} analogues exhibit SMM behavior as determined from ac susceptibility experiments in a zero static magnetic field. From DFT calculations a S=16 ground state was determined for the {Mn₈Y₈} complex due to weak ferromagnetic Mn^III–Mn^III interactions. Ab initio CASSCF+RASSI‐SO calculations on the {Mn₈Dy₈} wheel estimated the Mn^III–Dy^III exchange interaction as ?0.1 cm^?1. This weak exchange along with unfavorable single‐ion anisotropy of Dy^III/Mn^III ions, however, led to the observation of SMM behavior with fast magnetic relaxation. The orientation of the g‐anisotropy of the Dy^III ions is found to be perpendicular to the plane of the wheel and this suggests the possibility of toroidal magnetic moments in the cluster. The {Mn₈Ln₈} clusters reported here are the largest heterometallic Mn^IIILn^III wheels and the largest {3d–4f} wheels to exhibit SMM behavior reported to date.     

A new family of lanthanide coordination polymers based on 3,3′‐[(5‐carboxylato‐1,3‐phenylene)bis(oxy)]dibenzoate: synthesis,crystal structures and magnetic and luminescence properties

Six two‐dimensional (2D) coordination polymers (CPs), namely, poly[{μ₅‐3,3‐[(5‐carboxylato‐1,3‐phenylene)bis(oxy)]dibenzoato‐κ⁶O¹:O^1′:O³,O^3′:O⁵:O^5′}bis(N,N‐dimethylformamide‐κO)lanthanide(III)], [Ln(C₂₁H₁₁O₈)(C₃H₇NO)₂]_n, with lanthanide/Ln = cerium/Ce for CP1 , praseodymium/Pr for CP2 , neodymium/Nd for CP3 , samarium/Sm for CP4 , europium/Eu for CP5 and gadolinium/Gd for CP6 , have been prepared by solvothermal methods using the ligand 3,3′‐[(5‐carboxy‐1,3‐phenylene)bis(oxy)]dibenzoic acid (H₃cpboda) in the presence of Ln(NO₃)₃. The complexes were characterized by single‐crystal X‐ray and powder diffraction, IR spectroscopy, elemental analysis and thermogravimetric analysis (TGA). All the structures of this family of lanthanide CPs are isomorphous with the triclinic space group P and reveal that they have the same 2D network based on binuclear Ln^III units, which are further extended via interlayer C—H…π interactions into a three‐dimensional supramolecular structure. The carboxylate groups of the cpboda^3? ligands link adjacent Ln^III ions and form binuclear [Ln₂(RCOO)₄] secondary building units (SBUs), in which each binuclear Ln^III SBU contains four carboxylate groups from different cpboda^3? ligands. Moreover, with the increase of the rare‐earth Ln atomic radius, the dihedral angles between the aromatic rings gradually increase. Magnetically, CP6 shows weak antiferromagnetic coupling between the Gd^III ions. The solid‐state luminescence properties of CP2 , CP5 and CP6 were examined at ambient temperature and CP5 exhibits characteristic red emission bands derived from the Eu³⁺ ion (CIE 0.53, 0.31), with luminescence quantum yields of 22%. Therefore, CP5 should be regarded as a potential optical material.     

Controlled Synthesis of Heterotrimetallic Single‐Chain Magnets from Anisotropic High‐Spin 3 d–4 f Nodes and Paramagnetic Spacers

By using the node‐and‐spacer approach in suitable solvents, four new heterotrimetallic 1D chain‐like compounds (that is, containing 3d–3d′–4f metal ions), {[Ni(L)Ln(NO₃)₂(H₂O)Fe(Tp*)(CN)₃] ? 2 CH₃CN ? CH₃OH}_n (H₂L=N,N′‐bis(3‐methoxysalicylidene)‐1,3‐diaminopropane, Tp*=hydridotris(3,5‐dimethylpyrazol‐1‐yl)borate; Ln=Gd ( 1 ), Dy ( 2 ), Tb ( 3 ), Nd ( 4 )), have been synthesized and structurally characterized. All of these compounds are made up of a neutral cyanide‐ and phenolate‐bridged heterotrimetallic chain, with a {? Fe? C?N? Ni(? O? Ln)? N?C? }_n repeat unit. Within these chains, each [(Tp*)Fe(CN)₃]^? entity binds to the Ni^II ion of the [Ni(L)Ln(NO₃)₂(H₂O)]⁺ motif through two of its three cyanide groups in a cis mode, whereas each [Ni(L)Ln(NO₃)₂(H₂O)]⁺ unit is linked to two [(Tp*)Fe(CN)₃]^? ions through the Ni^II ion in a trans mode. In the [Ni(L)Ln(NO₃)₂(H₂O)]⁺ unit, the Ni^II and Ln^III ions are bridged to one other through two phenolic oxygen atoms of the ligand (L). Compounds 1 – 4 are rare examples of 1D cyanide‐ and phenolate‐bridged 3d–3d′–4f helical chain compounds. As expected, strong ferromagnetic interactions are observed between neighboring Fe^III and Ni^II ions through a cyanide bridge and between neighboring Ni^II and Ln^III (except for Nd^III) ions through two phenolate bridges. Further magnetic studies show that all of these compounds exhibit single‐chain magnetic behavior. Compound 2 exhibits the highest effective energy barrier (58.2 K) for the reversal of magnetization in 3d/4d/5d–4f heterotrimetallic single‐chain magnets.     

Heterometallic Clusters [CuSn3S9]5− and [Cu6Sn6S20]10−: Solvothermal Synthesis and Characterization of 4f–3d Thiostannates

Two types of 4f–3d thiostannates with general formula [Hen]₂[Ln(en)₄(CuSn₃S₉)] ? 0.5 en ( Ln1 ; Ln=La, 1 ; Ce, 2 ) and [Hen]₄[Ln(en)₄]₂[Cu₆Sn₆S₂₀] ? 3 en ( Ln2 ; Ln=Nd, 3 ; Gd, 4 ; Er, 5 ) were prepared by reactions of Ln₂O₃, Cu, Sn, and S in ethylenediamine (en) under solvothermal conditions between 160 and 190 °C. However, reactions performed in the range from 120 to 140 °C resulted in crystallization of [Sn₂S₆]^4? compounds and CuS powder. In 1 and 2 , three SnS₄ tetrahedra and one CuS₃ triangle are joined by sharing sulfur atoms to form a novel [CuSn₃S₉]^5? cluster that coordinates to the Ln³⁺ ion of [Ln(en)₄]³⁺ (Ln=La, Ce) as a monodentate ligand. The [CuSn₃S₉]^5? unit is the first thio‐based heterometallic adamantane‐like cluster coordinating to a lanthanide center. In 3 – 5 , six SnS₄ tetrahedra and six CuS₃ triangles are connected by sharing common sulfur atoms to form the ternary [Cu₆Sn₆S₂₀]^10? cluster, in which a Cu₆ core is enclosed by two Sn₃S₁₀ fragments. The topological structure of the novel Cu₆ core can be regarded as two Cu₄ tetrahedra joined by a common edge. The Ln³⁺ ions in Ln1 and Ln2 are in nine‐ and eightfold coordination, respectively, which leads to the formation of the [CuSn₃S₉]^5? and [Cu₆Sn₆S₂₀]^10? clusters under identical synthetic conditions. The syntheses of Ln1 and Ln2 show the influence of the lanthanide contraction on the quaternary Ln/Cu/Sn/S system in ethylenediamine. Compounds 1 – 5 exhibit bandgaps in the range of 2.09–2.48 eV depending on the two different types of clusters in the compounds. Compounds 1 , 3 , and 4 lost their organic components in the temperature range of 110–350 °C by multistep processes.     

Enhancement of TbIII–CuII Single‐Molecule Magnet Performance through Structural Modification

We report a series of 3d–4f complexes {Ln₂Cu₃(H₃L)₂X_n} (X=OAc^?, Ln=Gd, Tb or X=NO₃^?, Ln=Gd, Tb, Dy, Ho, Er) using the 2,2′‐(propane‐1,3‐diyldiimino)bis[2‐(hydroxylmethyl)propane‐1,3‐diol] (H₆L) pro‐ligand. All complexes, except that in which Ln=Gd, show slow magnetic relaxation in zero applied dc field. A remarkable improvement of the energy barrier to reorientation of the magnetisation in the {Tb₂Cu₃(H₃L)₂X_n} complexes is seen by changing the auxiliary ligands (X=OAc^? for NO₃^?). This leads to the largest reported relaxation barrier in zero applied dc field for a Tb/Cu‐based single‐molecule magnet. Ab initio CASSCF calculations performed on mononuclear Tb^III models are employed to understand the increase in energy barrier and the calculations suggest that the difference stems from a change in the Tb^III coordination environment (C_4v versus C_s).     

Nanostructuring phenomena in oxygen-conducting complex oxides of heavy REE

In complex oxides of REE (Ln₄M₃O₁₂ (Ln = Tm, Lu; M = Zr, Hf), Ln₂TiO₅ (Ln = Er-Yb)) and Ho₂TiO₅, the following phase transitions of the order-disorder type are studied for different cooling rates: rhombohedral δ-phase-defective fluorite in Ln₄M₃O₁₂ (Ln = Tm, Lu; M = Zr, Hf), pyrochlor-like phasedefective fluoride in Ln₂TiO₅ (Ln = Er-Yb), and hexagonal β-phase-pyrochlor in Ho₂TiO₅. The presence of nanostructuring phenomena typical of fluorite-like polymorphous modifications of complex oxides in the Ln₂O₃-MO₂ (Ln = Ho-Lu; M = Ti, Zr, Hf) systems is confirmed. The conductivity of polymorphous modifications of Ln₄Zr₃O₁₂ (Ln = Tm, Lu;) and Ln₂TiO₅ (Ln = Ho-Yb) with different thermal prehistory is studied. The comparative studies of the oxygen-ionic conductivity of fluorite- and pyrochlor-like Ln₂TiO₅ (Ln = Ho-Yb), pyrochlor Ho₂TiO₅, and β-Ho₂TiO₅ and also of the conductivity of fluorite-like compounds and δ-Ln₄Zr₃O₁₂ (Ln = Tm, Lu) are carried out. The oxygen-ionic conductivity of complex oxides in the Ln₂O₃-MO₂ (Ln = Er-Lu; M = Ti, Zr, Hf) system is shown to decrease in the following series: defective pyrochlor-defective fluorite-rhombohedral δ-phase ∼ hexagonal β-phase.     

New solid electrolytes of the pyrochlore family

The class of oxygen-ion-conducting rare-earth pyrochlores has been considerably extended. New solid electrolytes, Ln₂Ti₂O₇ (Ln = Dy-Lu) and Ln₂Hf₂O₇ (Ln = Eu, Gd) pyrochlores, are intrinsic ionic conductors at elevated temperatures, as are the well known Ln₂Zr₂O₇ (Ln = Sm-Gd) zirconates, which suggests that oxygen ion conduction in the rare-earth pyrochlore family has a general character. The thermodynamic order-disorder transitions that yield a PII cation- and anion-disordered pyrochlore phase possessing high oxygen ion conductivity occur throughout the rare-earth pyrochlore family: Ln₂M₂O₇ (Ln = Sm-Lu; M = Ti, Zr, Hf). The composition-structure-oxygen-ionic conductivity relationship is analyzed for Ln₂(M_{2 − x} Ln _x )O_{7 − δ} (Ln = Sm-Lu; M = Ti, Zr, Hf) with x from 0 to 0.81.     

Bis(phosphinimino)methanide Borohydride Complexes of the Rare‐Earth Elements as Initiators for the Ring‐Opening Polymerization of ε‐Caprolactone: Combined Experimental and Computational Investigations

Rare‐earth‐metal borohydrides are known to be efficient catalysts for the polymerization of apolar and polar monomers. The bis‐borohydrides [{CH(PPh₂NSiMe₃)₂}La(BH₄)₂(THF)] and [{CH(PPh₂NSiMe₃)₂}Ln(BH₄)₂] (Ln=Y, Lu) have been synthesized by two different synthetic routes. The lanthanum and the lutetium complexes were prepared from [Ln(BH₄)₃(THF)₃] and K{CH(PPh₂NSiMe₃)₂}, whereas the yttrium analogue was obtained from in situ prepared [{CH(PPh₂NSiMe₃)₂}YCl₂]₂ and NaBH₄. All new compounds were characterized by standard analytical/spectroscopic techniques, and the solid‐state structures were established by single‐crystal X‐ray diffraction. The ring‐opening polymerization (ROP) of ε‐caprolactone initiated by [{CH(PPh₂NSiMe₃)₂}La(BH₄)₂(THF)] and [{CH(PPh₂NSiMe₃)₂}Ln(BH₄)₂] (Ln=Y, Lu) was studied. At 0 °C the molar mass distributions determined were the narrowest values (M?_w/M?_n=1.06–1.11) ever obtained for the ROP of ε‐caprolactone initiated by rare‐earth‐metal borohydride species. DFT investigations of the reaction mechanism indicate that this type of complex reacts in an unprecedented manner with the first B? H activation being achieved within two steps. This particularity has been attributed to the metallic fragment based on the natural bond order analysis.     

Synthesis,Magnetism, and Thermostability of a Series of Two‐Dimensional Lanthanide–Nickel Heterometallic Coordination Polymers

A series of Ln–Ni heterometallic coordination polymers, {[Ln₂Ni(MIDA)₄(H₂O)₆](H₂O)₄} (Ln = La ( 1 ), Ce ( 2 ), Pr ( 3 ), and Nd ( 4 ); H₂MIDA = N‐methyl‐iminodiacetic acid), were obtained under hydrothermal conditions. Single crystal X‐ray diffraction revealed that they feature two‐dimensional isomorphic frameworks, which could be viewed as the construction by one‐dimensional {Ln}_n chain connecting by bridges of [Ni(MIDA)₂]². The magnetic measurements reveal that compounds 2 – 4 exhibit antiferromagnetic properties. TGA results indicate compounds 1 and 4 have good thermostability with the critical temperature of 375 °C.     

Slow Magnetic Relaxation and Single‐Molecule Toroidal Behaviour in a Family of Heptanuclear {CrIIILnIII6} (Ln=Tb,Ho, Er) Complexes

The synthesis, magnetic properties, and theoretical studies of three heterometallic {Cr^IIILn^III₆} (Ln=Tb, Ho, Er) complexes, each containing a metal topology consisting of two Ln₃ triangles connected via a Cr^III linker, are reported. The {CrTb₆} and {CrEr₆} analogues display slow relaxation of magnetization in a 3000 Oe static magnetic field. Single‐crystal measurements reveal opening up of the hysteresis loop for {CrTb₆} and {CrHo₆} molecules at low temperatures. Ab initio calculations predict toroidal magnetic moments in the two Ln₃ triangles, which are found to couple, stabilizing a con‐rotating ferrotoroidal ground state in Tb and Ho examples and extend the possibility of observing toroidal behaviour in non Dy^III complexes for the first time.     

Slow Magnetic Relaxation and Single‐Molecule Toroidal Behaviour in a Family of Heptanuclear {CrIIILnIII6} (Ln=Tb,Ho, Er) Complexes

The synthesis, magnetic properties, and theoretical studies of three heterometallic {Cr^IIILn^III₆} (Ln=Tb, Ho, Er) complexes, each containing a metal topology consisting of two Ln₃ triangles connected via a Cr^III linker, are reported. The {CrTb₆} and {CrEr₆} analogues display slow relaxation of magnetization in a 3000 Oe static magnetic field. Single‐crystal measurements reveal opening up of the hysteresis loop for {CrTb₆} and {CrHo₆} molecules at low temperatures. Ab initio calculations predict toroidal magnetic moments in the two Ln₃ triangles, which are found to couple, stabilizing a con‐rotating ferrotoroidal ground state in Tb and Ho examples and extend the possibility of observing toroidal behaviour in non Dy^III complexes for the first time.     

Structural Diversity of Infinite 3d–4f Heterometallic Cluster Compounds Driven by Various Lanthanide Radii

The syntheses, structures, and characterization of six Ln³⁺–Cu²⁺–glycine (Hgly) coordination polymers are described in this paper. They represent three types of structures. Type I (Ln=La ( 1 ), Pr ( 2 ), and Sm ( 3 )) is a 1D catenarian polymer comprising [Ln₂] nodes bridged by four cis‐Cu(gly)₂ linkers. Type II (Ln=Eu ( 4 ) and Dy ( 5 )) is a 2D open framework with a 4⁴‐net, composed of novel [Ln₆Cu₂₂] cluster nodes linked by trans‐Cu(gly)₂ linkers. Furthermore, the inner structures of the [Ln₆Cu₂₂] nodes, and the connection mode between the nodes and linkers are slightly different for 4 and 5 . Type III (Ln=Er ( 6 )) is a 3D open framework with a novel 3⁶?4¹⁸?5³?6 topology, made up of [Er₆Cu₂₄] cluster nodes and trans‐Cu(gly)₂ linkers. The rich variety of the resulting structures owes itself mainly to the interselection between the dynamic control of metalloligands and cationic components. A transition from frequency dependence to frequency independence is observed in the field‐induced magnetization lag for 1 – 3 . The frequency dependence at low temperatures may come from the antiferromagnetic Cu? Cu interaction through the [Ln₂] nodes, whereas the frequency independence may be due to the disappearance of the antiferromagnetic Cu? Cu interaction at high temperatures.     

Following the Reaction of Heteroanions inside a {W18O56} Polyoxometalate Nanocage by NMR Spectroscopy and Mass Spectrometry

By incorporating phosphorus(III)‐based anions into a polyoxometalate cage, a new type of tungsten‐based unconventional Dawson‐like cluster, [W₁₈O₅₆(HP^IIIO₃)₂(H₂O)₂]^8?, was isolated, in which the reaction of the two phosphite anions [HPO₃]^2? within the {W₁₈O₅₆} cage could be followed spectroscopically. As well as full X‐ray crystallographic analysis, we studied the reactivity of the cluster using both solution‐state NMR spectroscopy and mass spectrometry. These techniques show that the cluster undergoes a structural rearrangement in solution whereby the {HPO₃} moieties dimerize to form a weakly interacting (O₃PH???HPO₃) moiety. In the crystalline state the cluster exhibits a thermally triggered oxidation of the two P^III template moieties to form P^V centers (phosphite to phosphate), commensurate with the transformation of the cage into a Wells–Dawson {W₁₈O₅₄} cluster.