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.     

Lanthanide oxalatophosphonates with two- and three-dimensional structures

Reactions of lanthanide nitrate, oxalate sodium and 2-pyridylmethylphosphonic acid (2-pmpH₂) under hydrothermal conditions result in five new lanthanide oxalatophosphonates with two types of structures. Compounds [Ln₄(ox)₅(2-pmpH)₂(H₂O)₇]·5H₂O [Ln³⁺=Gd (1), Tb (2), Dy (3); ox²⁻=C₂O₄²⁻] exhibit a double layer structure, made up of net-like {Ln₄(ox)₅}_n layers containing Ln₁₀(ox)₁₀ rings which are connected by 2-pmpH^‐. While compounds [Ln₄(ox)₅(2-pmpH)₂(H₂O)₆]·6H₂O [Ln³⁺=Ho (4), Yb (5)] display a three-dimensional framework structure in which the {Ln₄(ox)₅}_n layers are cross-linked by 2-pmpH. The solid state luminescent and magnetic properties are investigated.     

Cluster cyanide-bridged heterometallic coordination polymers: synthesis and crystal structures of compounds [{Cu2(dien)2(CN)}2{Mo4Te4(CN)12}]·14.5H2O and (H3O)3K[{Mn(H2O)2}2{Mn(H2O)2(NO3)}4{W4Te4(CN)12}2]·8H2O

The reactions of anionic molybdenum and tungsten cyanide cuboidal clusters with Cu^II and Mn^II salts afforded two new cyanide-bridged heterometallic coordination polymers with the composition [{Cu₂(dien)₂(CN)}₂{Mo₄Te₄(CN)₁₂}]?14.5H₂O (1) and (H₃O)₃K[{Mn(H₂O)₂}₂{Mn(H₂O)₂(NO₃)}₄{W₄Te₄(CN)₁₂}₂]·8H₂O (2). The structures of these compounds were established by X-ray diffraction analysis. Compound 1 has a layered structure, in which the cuboidal cluster fragments {Mo₄Te₄(CN)₁₂}^6? are linked to the copper atoms of the dinuclear fragments {(H₂O)(dien)Cu(μ-CN)Cu(dien)(H₂O)} through the bridging CN groups. Coordination polymer 2 has a framework structure, in which the cluster fragments {W₄Te₄(CN)₁₂}^6? are linked to the manganese(II) aqua complexes of two types, viz., the dinuclear fragment {Mn(μ₂-H₂O)₂Mn} and the tetranuclear cyclic fragment {(H₂O)₂Mn(μ₂-NO₃)}₄, through the bridging CN groups.     

On the Lanthanide Ferrocyanides KLnFe(II)(CN)6·xH2O (Ln=La-Lu): Characterization and Thermal Evolution

The properties of a series of lanthanide hexacyanoferrate(II) n-hydrates were studied by thermal analysis, IR spectroscopy and X-ray diffraction. Thermal analysis results show that there are three kinds of complexes in this series, KLn[Fe(CN)₆]·4 H₂O (Ln=La-Nd), KSm[Fe(CN)₆]·3H₂O and KLn[Fe (CN)₆]·3.5H₂O (Ln=Eu-Lu). On the basis of IR spectra, only two different types of complexes show obvious differences. Indeed for the tetrahydrates, there is one OH stretching band; on the other hand, for the samarium phase and the 3.5 hydrates a splitting of HOH stretching mode is observed. The splitting of the H₂O band is correlated to a symmetry modification. The crystal structures of the three complexes KLn[Fe(CN)₆]·3.5H₂O (Ln=Eu, Er and Lu) were determined; they belong to orthorhombic symmetry (space group Cmcm). Heat-treated powders have been investigated by X-ray analysis which show the formation of thin needles of LnFeO₃ at 600°C.     

Photomagnetic Switching of Heterometallic Complexes [M(dmf)4(H2O)3(μ‐CN)Fe(CN)5]⋅H2O (M=Nd,La, Gd,Y) Analyzed by Single‐Crystal X‐ray Diffraction and Ab Initio Theory

Single‐crystal X‐ray diffraction measurements have been carried out on [Nd(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 1 ; dmf=dimethylformamide), [Nd(dmf)₄(H₂O)₃(μ‐CN)Co(CN)₅]?H₂O ( 2 ), [La(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 3 ), [Gd(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 4 ), and [Y(dmf)₄(H₂O)₃(μ‐CN)Fe(CN)₅]?H₂O ( 5 ), at 15(2) K with and without UV illumination of the crystals. Significant changes in unit‐cell parameters were observed for all the iron‐containing complexes, whereas 2 showed no response to UV illumination. Photoexcited crystal structures have been determined for 1 , 3 , and 4 based on refinements of two‐conformer models, and excited‐state occupancies of 78.6(1), 84(6), and 86.6(7) % were reached, respectively. Significant bond‐length changes were observed for the Fe–ligand bonds (up to 0.19 Å), the cyano bonds (up to 0.09 Å), and the lanthanide–ligand bonds (up to 0.10 Å). Ab initio theoretical calculations were carried out for the experimental ground‐state geometry of 1 to understand the electronic structure changes upon UV illumination. The calculations suggest that UV illumination gives a charge transfer from the cyano groups on the iron atom to the lanthanide ion moiety, {Nd(dmf)₄(H₂O)₃}, with a distance of approximately 6 Å from the iron atom. The charge transfer is accompanied by a reorganization of the spin state on the {Fe(CN)₆} complex, and a change in geometry that produces a metastable charge‐transfer state with an increased number of unpaired electrons, thus accounting for the observed photomagnetic effect.     

Structural features of copper(II) and lanthanide(III) tartratogermanate(IV) complexes

Four heterometallic tartratogermanate complexes, namely [Cu₂Ge₂(Tart)₃(H₂O)₁₀] _n · 3nH₂O and (H₃O)[LnGe₂(Tart)₃(H₂O)₆] · nH₂O (Ln³⁺ = Gd, n = 3.5; Tm, n = 3; Yb, n = 3), have been prepared via the reaction between germanium tetrachloride and D-tartaric acid (H₄Tart) in aqueous acetic acid. All complexes contain {Ge₂(Tart)₃} _n ^4n- polymer chains. The Cu²⁺ and Ln³⁺ atoms coordinate only Tart carbonyl oxygen atoms.     

Visible light-induced magnetization change of the cyano-bridged 3d-4f heterobimetallic

A visible light-induced magnetization change of the 3d-4f heterometallic, [Nd(DMF)₄(H₂O)₃(μ-NC)Co(CN)₅]·H₂O (DMF=N,N-dimethylformamide), is observed and described. The plots of χ_MT versus T of the complex showed that the χ_MT values, after visible light illumination, were enhanced by about 25% as compared to before irradiation in the temperature range of 5-40 K.     

The Building Block [FeIII(pzphen)(CN)4]– and its Lanthanide Complexes: Synthesis,Crystal Structure,and Magnetic Properties

The cyanide building block [Fe^III(pzphen)(CN)₄]^– and its four lanthanide complexes [{Fe^III(pzphen)(CN)₄}₂Ln^III(H₂O)₅(DMF)₃] · (NO₃) · 2(H₂O) · (CH₃CN) [Ln = Nd ( 1 ), Sm ( 2 ), DMF = dimethyl formamide] and [{Fe^III(pzphen)(CN)₄}₂Ln^III(NO₃)(H₂O)₂(DMF)₂](CH₃CN) [Ln = Gd ( 3 ), Dy ( 4 )] were synthesized and structurally characterized by single‐crystal X‐ray diffraction. Compounds 1 and 2 are ionic salts with two [Fe^III(pzphen)(CN)₄]^– cations and one Ln^III ion, but compounds 3 and 4 are cyano‐bridged Fe^III‐Ln^III heterometallic 3d‐4f complexes exhibiting a trinuclear structure in the same conditions. Magnetic studies show that compound 3 is antiferromagnetic between the central Fe^III and Gd^III atoms. Furthermore, the trinuclear cyano‐bridged Fe^III₂Dy^III compound 4 displays no single‐molecular magnets (SMMs) behavior by the alternating current magnetic susceptibility measurements.     

Heterotrimetallic Coordination Polymers: {CuIILnIIIFeIII} Chains and {NiIILnIIIFeIII} Layers: Synthesis,Crystal Structures,and Magnetic Properties

The use of the [Fe^III(AA)(CN)₄]^? complex anion as metalloligand towards the preformed [Cu^II(valpn)Ln^III]³⁺ or [Ni^II(valpn)Ln^III]³⁺ heterometallic complex cations (AA=2,2′‐bipyridine (bipy) and 1,10‐phenathroline (phen); H₂valpn=1,3‐propanediyl‐bis(2‐iminomethylene‐6‐methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu^II(valpn)Ln^III(H₂O)₃(μ‐NC)₂Fe^III(phen)(CN)₂ {(μ‐NC)Fe^III(phen)(CN)₃}]NO₃ ? 7 H₂O}_n (Ln=Gd ( 1 ), Tb ( 2 ), and Dy ( 3 )) and the trinuclear complex [Cu^II(valpn)La^III(OH₂)₃(O₂NO)(μ‐NC)Fe^III(phen)(CN)₃] ? NO₃ ? H₂O ? CH₃CN ( 4 ) were obtained with the [Cu^II(valpn)Ln^III]³⁺ assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni^II(valpn)Ln^III(ONO₂)₂(H₂O)(μ‐NC)₃Fe^III(bipy)(CN)] ? 2 H₂O ? 2 CH₃CN}_n (Ln=Gd ( 5 ), Tb ( 6 ), and Dy ( 7 )) resulted with the related [Ni^II(valpn)Ln^III]³⁺ precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu^II(valpn)La^III(OH₂)₃(O₂NO)(μ‐NC)Fe^III(phen)(CN)₃]⁺, nitrate counterions, and non‐coordinate water and acetonitrile molecules. The heteroleptic {Fe^III(bipy)(CN)₄} moiety in 5 – 7 acts as a tris‐monodentate ligand towards three {Ni^II(valpn)Ln^III} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu^II?Ln^III ( 1 – 3 ) and Ni^II?Ln^III ( 5 – 7 ) units, as well as through the single cyanide bridge between the Fe^III and either Ni^II ( 5 – 7 ) or Cu^II ( 4 ) account for the overall ferromagnetic behavior observed in 1 – 7 . DFT‐type calculations were performed to substantiate the magnetic interactions in 1 , 4 , and 5 . Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out‐of‐phase ac signals below 4.0 K in the lack of a dc field, the values of the pre‐exponential factor (τ_o) and energy barrier (E_a) through the Arrhenius equation being 2.0×10^?12 s and 29.1 cm^?1, respectively. In the case of 7 , the ferromagnetic interactions through the double phenoxo (Ni^II–Dy^III) and single cyanide (Fe^III–Ni^II) pathways are masked by the depopulation of the Stark levels of the Dy^III ion, this feature most likely accounting for the continuous decrease of χ_M T upon cooling observed for this last compound.     

Synthesis,crystal structure and magnetic properties of the cyano-bridged heteropolynuclear complex [{(Cu(dien))2Co(CN)6}n][Cu(dien)(H2O)Co(CN)6]n·5nH2O

The reaction of [Cu(dien)(H₂O)](NO₃)₂ with K₃[Co(CN)₆] leads to the cyano-bridged heteropolynuclear complex, [{(Cu(dien))₂Co(CN)₆}_n][Cu(dien)(H₂O)Co(CN)₆]_n·5nH₂O, {Cu₃Co₂}, whose crystal structure has been solved. The structure consists of two distinct ionic units, namely one-dimensional cationic chains [{(Cu(dien))₂Co(CN)₆}_n]ⁿ⁺, and discrete binuclear anionic entities [(H₂O)(dien)Cu–NC–Co(CN)₅]⁻. The cryomagnetic investigation of the title compound reveals a very weak antiferromagnetic coupling between the Cu(II) ions within the cationic chain (J=−1.02 cm⁻¹, g=2.14). The complete elimination of the water molecules from the isomorphous {Cu₃Co₂}, {Cu₃Fe₂} and {Cu₃Cr₂} complexes causes the modification of the magnetic properties. The most dramatic one is observed with the Cu(II)–Fe(III) system, where the magnetic behavior changes from ferro- to antiferromagnetic. The dehydrated chromium derivative preserves the ferromagnetic coupling, which is observed at lower temperatures (below 30 K) in comparison with the parent compound (below 150 K).     

4,5‐Dichlorophthalate‐Extended Lanthanide Coordination Polymers with Layer and Ribbon Motifs: Synthesis,Structure, and Luminescence

Five new 4,5‐dichlorophthalate (dcpa)‐extended lanthanide coordination polymers (CPs) with formulas [Ln₂(H₂O)(dcpa)₃]_n (Ln = Tb for 1 , Sm for 2 , Pr for 3 , and Nd for 4 ) and [Yb(H₂O)₂(dcpa)(Hdcpa)]_n ( 5 ) were solvothermally synthesized. Structural determinations demonstrate that CPs 1 – 4 are crystallographically isostructural, exhibiting an infinite two‐dimensional layer with dimeric {Ln₂(COO)₃} subunits extended by aromatic skeleton of fully deprotonated dcpa^2– connectors. In contrast, complex 5 features a one‐dimensional broad ribbon with centrosymmetric {Yb₂(COO)₂} subunits propagated by pairs of ditopic dcpa^2– ligands. Interestingly, the anionic dcpa^2– connector can serve as a good antenna ligand to sensitize the characteristic emissions of the different Ln^III ions in both the ultraviolet (for 1 – 3 ) and near‐infrared (for 4 and 5 ) regions.     

Rare-earth cobalticyanides LnCo(CN)6·nH2O

Crystalline cobalticyanides LnCo^III(CN)₆·nH₂O with Ln = La,…, Lu, Y have been synthesized by a double-infusion technique. In analogy to the Cr and Fe compounds, the large rare-earth ions form a hexagonal modification while the smaller ions lead to the orthorhombic structure with 4H₂O. Experiments show that no magnetic ordering occurs down to 1°K. The Stark splitting of the J ground state due to the crystalline field is analyzed for the Ce and Sm compounds.     

Two types of coordination polymers based on cluster anions [Re4Q4(CN)12] (Q = S, Se) and cations of rare-earth metals Ln: Syntheses and crystal structures

The reactions of aqueous solutions of the tetrahedral cluster anions [Re₄Q₄(CN)₁₂]⁴⁻ (Q = S, Se) with lanthanide chlorides resulted in the crystallization of the formed compounds into two main structural types [{Ln(H₂O)₄(H₂O)_2/3Cl_1/3}₃{Re₄Q₄(CN)₁₂}₂]·2H₂O (Ln = La-Gd, Q = S, Se) and K_0.5(H)_0.5[{Ln(H₂O)₄}{Re₄S₄(CN)₁₂}]·nH₂O or (H)[{Ln(H₂O)₄}{Re₄Se₄(CN)₁₂}]·nH₂O (Ln = Tb-Lu). Compounds of the first type crystallize in the hexagonal crystal system (space group Р6₃/m) and they have a three-dimensional polymeric structure; compounds of the second type crystallize in the orthorhombic crystal system (space group Cmcm) and they have a two-dimensional crystal structure due to the polymeric anion {[{Ln(H₂O)₄}{Re₄Q₄(CN)₁₂}]⁻}_∞∞.     

The influence of organic agents on the resultant crystal structure in the reactions of the [Re4Te4(CN)12] tetrahedral cluster anion with Nd cations

The reaction of the cluster salt K₄[Re₄Te₄(CN)₁₂]·5H₂O with NdCl₃·6H₂O was studied in either an acidic medium (HCl) or in a water solution in the presence of the following organic agents: hexafluoroacetylacetonate, 2,2′-bipyridine or 1,10-phenanthroline (phen). The crystal structures of four new compounds have been solved by single crystal X-ray diffraction analysis: (H)[{Nd(H₂O)₅}{Re₄Te₄(CN)₁₂}]·5.5H₂O (1) (space group P2₁/c, framework structure), K₂[{Nd(H₂O)₇}₂{Re₄Te₄(CN)₁₂}₂]·8H₂O (2) (space group С2/c, isolated structure), K_0.5H_0.5[{Nd(H₂O)₅}{Re₄Te₄(CN)₁₂}]·3H₂O (3) (space group Сmcm, layered structure) and (phenH)[{Nd(H₂O)₂(phen)₂}{Re₄Te₄(CN)₁₂}]·11H₂O (4) (space group С2/c, chain structure). 1,10-Phenanthroline was found to have been incorporated into the structure of compound 4, whilst hexafluoroacetylacetonate and 2,2′-bipyridine did not enter the structures of 2 and 3. It was shown that the structures of compounds 2-4 differ dramatically from that found for compound 1, which was obtained in the absence of the organic agents.     

Zur Chemie des Dimesityleisens. X. Mesityleisenkomplexe [FeMes(X)]2 mit zentraler {Fe2(μ-Mes)2}-Einheit (Mes = C6H2-2,4,6-(CH3)3)

Chemistry of Dimesityl Iron. X. Mesityl Iron Complexes [FeMes(X)]₂ with a Central {Fe₂(μ-Mes)₂} Unit (Mes = C₆H₂-2,4,6-(CH₃)₃) Dimeric complexes [{MesFe(OAryl)}₂] with coordination number (CN) of 3 are obtained from Fe₂Mes₄ 1 by partial acidolyses with 2,6-di-tert-butyl-substituted phenols (HOAryl). 1 reacts with 1,3-diketones in a molar ratio of 1:2 to [{MesFe(diketonate)}₂] with CN 4. A central {Fe₂(μ-Mes)₂}-unit with short Fe—Fe distances of 2.56 to 2.63 Å ( 1: 2.615 Å) is found in both types of complexes. The mixed ligand complexes react with an excess of phenol or diketone to {Fe(OAryl)₂} or {Fe(diketonate)₂}, respectively. 1 reacts with HOAryl in the molar ratio of 1:1 to [Fe₂(μ-Mes)₂Mes(OAryl)]. The structures of [Fe₂(μ-Mes)₂(OC₆H₂-2,6-tBu₂-4-CH₃)₂] ( 3 ), [Fe₂(μ-Mes)₂Mes(OC₆H₂-2,4,6-tBu₃)] ( 5 ) and [Fe₂(μ-Mes)₂{(tBuCO)₂CH}₂] ( 9 ) are presented.     

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.     

Thermal decomposition of lighter lanthanide selenate hydrates and their solid solutions

The thermal dehydration-decomposition of Ln₂(SeO₄)₃·nH₂O (wheren=12 forLn=Pr, Nd andn=8 forLn=Sm) and Pr_xLn_2−x(SeO₄)₃·nH₂O (wheren=12 forx=1.0 andLn=Nd;n=8 forx=0.2 and 1.0 in case ofLn=Sm) have been reported.

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Zusammenfassung Die thermische Dehydratation-Zersetzung von Ln₂(SeO₄)₃·nH₂O (mitn=12 fürLn=Pr, Nd undn=8 fürLn=Sm) und Pr_xLn_2−x(SeO₄)₃·nH₂O (mitn=12 fürx=1.0 undLn=Nd;n=8 fürx=0.2 und 1.0 in Falle vonLn=Sm) wurde beschrieben.

     

[MII(H2dapsc)]-[Cr(CN)6] (M = Mn,Co) Chain and Trimer Complexes: Synthesis,Crystal Structure,Non-Covalent Interactions and Magnetic Properties

Four new heterometallic complexes combining [M^II(H₂dapsc)]²⁺ cations with the chelating H₂dapsc {2,6-diacetylpyridine-bis(semicarbazone)} Schiff base ligand and [Cr(CN)₆]³⁻ anion were synthesized: {[M^II(H₂dapsc)]Cr^III(CN)₆K(H₂O)_2.5(EtOH)_0.5}_n·1.2n(H₂O), M = Mn (1) and Co (2), {[Mn(H₂dapsc)]₂Cr(CN)₆(H₂O)₂}Cl·H₂O (3) and {[Co(H₂dapsc)]₂Cr(CN)₆(H₂O)₂}Cl·2EtOH·3H₂O (4). In all the compounds, M(II) centers are seven-coordinated by N₃O₂ atoms of H₂dapsc in the equatorial plane and N or O atoms of two apical –CN/water ligands. Crystals 1 and 2 are isostructural and contain infinite negatively charged chains of alternating [M^II(H₂dapsc)]²⁺ and [Cr^III(CN)₆]³⁻ units linked by CN-bridges. Compounds 3 and 4 consist of centrosymmetric positively charged trimers in which two [M^II(H₂dapsc)]²⁺ cations are bound through one [Cr^III(CN)₆]³⁻ anion. All structures are regulated by π-stacking of coplanar H₂dapsc moieties as well as by an extensive net of hydrogen bonding. Adjacent chains in 1 and 2 interact also by coordination bonds via a pair of K⁺ ions. The compounds containing Mn^II (1, 3) and Co^II (2, 4) show a significant difference in magnetic properties. The ac magnetic measurements revealed that complexes 1 and 3 behave as a spin glass and a field-induced single-molecule magnet, respectively, while 2 and 4 do not exhibit slow magnetic relaxation in zero and non-zero dc fields. The relationship between magnetic properties and non-covalent interactions in the structures 1–4 was traced.     

Framework polymers based on octahedral chalcocyanide cluster [Re6Q8(CN)6]4−/3− anions (Q = Se, Te) and [Nd(Bipy)n]3+ Complexes (n = 1, 2)

Interaction of salts of the cluster anions {Re [Re₆Q₈(CN)₆]^4?/3? (Q = Se, Te) with Nd salts in the presence of 2,2′-bipyridyl (Bipy) ligand brings about new coordination polymers: Pr ₄ ⁿ N[{Nd(Bipy)(H₂O)₄} {Re₆Se₈(CN)₆}] · 2H₂O (I) (space group C2/c, a = 18.2918(16) Å, b = 14.9972(13) Å, c = 37.513(3) Å, β = 102.046(4)°, V = 10064.2(15) ų, Z = 8), [{Nd(Bipy)₂(H₂O)} {Re₆Se₈(CN)₆}] (II) (space group C2/c, a = 15.8668(3) Å, b = 13.5403(3) Å, c = 20.5189(4) Å, β = 110.135(1)°, V = 4138.89(15) Å₃, Z = 4), and [{Nd(Bipy)(EtOH)(H₂O)₄}{Re₆Te₈(CN)₆}] · EtOH (III) (space group $P\bar 1$ , a = 9.4733(6) Å, b = 12.5326(8) Å, c = 17.2374(11) Å, α = 96.561(2)°, β = 90.310(2)°, γ = 94.876(2)°, V = 4138.89(15) Å₃, Z = 4). The compounds synthesized are characterized by single-crystal X-ray diffraction and IR methods. Compounds I and III have layered (2D) structures, compound II is a framework (3D) polymer.     

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.