One‐Dimensional Ferromagnetically Coupled Bimetallic Chains Constructed with trans‐[Ru(acac)2(CN)2]−: Syntheses,Structures, Magnetic Properties,and Density Functional Theoretical Study

Four cyano‐bridged 1D bimetallic polymers have been prepared by using the paramagnetic building block trans‐[Ru(acac)₂(CN)₂]^? (Hacac=acetylacetone): {[{Ni(tren)}{Ru(acac)₂(CN)₂}][ClO₄]?CH₃OH}_n ( 1 ) (tren=tris(2‐aminoethyl)amine), {[{Ni(cyclen)}{Ru(acac)₂(CN)₂}][ClO₄]? CH₃OH}_n ( 2 ) (cyclen=1,4,7,10‐tetraazacyclododecane), {[{Fe(salen)}{Ru(acac)₂(CN)₂}]}_n ( 3 ) (salen^2?=N,N′‐bis(salicylidene)‐o‐ethyldiamine dianion) and [{Mn(5,5′‐Me₂salen)}₂{Ru(acac)₂(CN)₂}][Ru(acac)₂(CN)₂]? 2 CH₃OH ( 4 ) (5,5′‐Me₂salen=N,N′‐bis(5,5′‐dimethylsalicylidene)‐o‐ethylenediimine). Compounds 1 and 2 are 1D, zigzagged NiRu chains that exhibit ferromagnetic coupling between Ni^II and Ru^III ions through cyano bridges with J=+1.92 cm^?1, z J′=?1.37 cm^?1, g=2.20 for 1 and J=+0.85 cm^?1, z J′=?0.16 cm^?1, g=2.24 for 2 . Compound 3 has a 1D linear chain structure that exhibits intrachain ferromagnetic coupling (J=+0.62 cm^?1, z J′=?0.09 cm^?1, g=2.08), but antiferromagnetic coupling occurs between FeRu chains, leading to metamagnetic behavior with T_N=2.6 K. In compound 4 , two Mn^III ions are coordinated to trans‐[Ru(acac)₂(CN)₂]^? to form trinuclear Mn₂Ru units, which are linked together by π–π stacking and weak Mn???O* interactions to form a 1D chain. Compound 4 shows slow magnetic relaxation below 3.0 K with ?=0.25, characteristic of superparamagnetic behavior. The Mn^III???Ru^III coupling constant (through cyano bridges) and the Mn^III???Mn^III coupling constant (between the trimers) are +0.87 and +0.24 cm^?1, respectively. Compound 4 is a novel single‐chain magnet built from Mn₂Ru trimers through noncovalent interactions. Density functional theory (DFT) combined with the broken symmetry state method was used to calculate the molecular magnetic orbitals and the magnetic exchange interactions between Ru^III and M (M=Ni^II, Fe^III, and Mn^III) ions. To explain the somewhat unexpected ferromagnetic coupling between low‐spin Ru^III and high‐spin Fe^III and Mn^III ions in compounds 3 and 4 , respectively, it is proposed that apart from the relative symmetries, the relative energies of the magnetic orbitals may also be important in determining the overall magnetic coupling in these bimetallic assemblies.     

Enhanced Single‐Chain Magnet Behavior via Anisotropic Exchange in a Cyano‐Bridged MoIII–MnII Chain

Anisotropic magnetic exchange is of great value for the design of high performance molecular nanomagnets. In the present work, enhanced single‐chain magnet (SCM) behavior is observed for a Mo^III–Mn^II chain that exhibits anisotropic magnetic exchange. Self‐assembly of the pentagonal bipyramidal [Mo(CN)₇]^4? anion and the Mn^II unit with a tridentate ligand results in a neutral double zigzag 2,4‐ribbon structure which exhibits SCM behavior with a high relaxation barrier of 178(4) K. Open magnetic hysteresis loops are observed below 5.2 K, with a coercive field of 1.5 T at 2 K. Interestingly, this SCM can be considered to be a result of a step‐wise process based on our previously reported Mn₂Mo single‐molecule magnets (SMMs).     

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.     

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.     

Insertion of a Single‐Molecule Magnet inside a Ferromagnetic Lattice Based on a 3D Bimetallic Oxalate Network: Towards Molecular Analogues of Permanent Magnets

The insertion of the single‐molecule magnet (SMM) [Mn^III(salen)(H₂O)]₂²⁺ (salen^2?=N,N′‐ethylenebis‐(salicylideneiminate)) into a ferromagnetic bimetallic oxalate network affords the hybrid compound [Mn^III(salen)(H₂O)]₂[Mn^IICr^III(ox)₃]₂ ? (CH₃OH) ? (CH₃CN)₂ ( 1 ). This cationic Mn₂ cluster templates the growth of crystals formed by an unusual achiral 3D oxalate network. The magnetic properties of this hybrid magnet are compared with those of the analogous compounds [Mn^III(salen)(H₂O)]₂[Zn^IICr^III(ox)₃]₂ ? (CH₃OH) ? (CH₃CN)₂ ( 2 ) and [In^III(sal₂‐trien)][Mn^IICr^III(ox)₃] ? (H₂O)_0.25 ? (CH₃OH)_0.25 ? (CH₃CN)_0.25 ( 3 ), which are used as reference compounds. In 2 it has been shown that the magnetic isolation of the Mn₂ clusters provided by their insertion into a paramagnetic oxalate network of Cr^III affords a SMM behavior, albeit with blocking temperatures well below 500 mK even for frequencies as high as 160 kHz. In 3 the onset of ferromagnetism in the bimetallic Mn^IICr^III network is observed at T_c=5 K. Finally, in the hybrid compound 1 the interaction between the two magnetic networks leads to the antiparallel arrangement of their respective magnetizations, that is, to a ferrimagnetic phase. This coupling induces also important changes on the magnetic properties of 1 with respect to those of the reference compounds 2 and 3 . In particular, compound 1 shows a large magnetization hysteresis below 1 K, which is in sharp contrast with the near‐reversible magnetizations that the SMMs and the oxalate ferromagnetic lattice show under the same conditions.     

Chemisorption of Exchange‐Coupled [Ni2L(dppba)]+ Complexes on Gold by Using Ambidentate 4‐(Diphenylphosphino)benzoate Co‐Ligands

A new strategy for the fixation of redox‐active dinickel(II) complexes with high‐spin ground states to gold surfaces was developed. The dinickel(II) complex [Ni₂L(Cl)]ClO₄ ( 1 ClO₄), in which L^2? represents a 24‐membered macrocyclic hexaaza‐dithiophenolate ligand, reacts with ambidentate 4‐(diphenylphosphino)benzoate (dppba) to form the carboxylato‐bridged complex [Ni₂L(dppba)]⁺, which can be isolated as an air‐stable perchlorate [Ni₂L(dppba)]ClO₄ ( 2 ClO₄) or tetraphenylborate [Ni₂L(dppba)]BPh₄ ( 2 BPh₄) salt. The auration of 2 ClO₄ was probed on a molecular level, by reaction with AuCl, which leads to the monoaurated Ni^II₂Au^I complex [Ni^II₂L(dppba)Au^ICl]ClO₄ ( 3 ClO₄). Metathesis of 3 ClO₄ with NaBPh₄ produces [Ni^II₂L(dppba)Au^IPh]BPh₄ ( 4 BPh₄), in which the Cl^? is replaced by a Ph^? group. The complexes were fully characterized by ESI mass spectrometry, IR and UV/Vis spectroscopy, X‐ray crystallography ( 2 BPh₄ and 4 BPh₄), cyclic voltammetry, SQUID magnetometry and HF‐ESR spectroscopy. Temperature‐dependent magnetic susceptibility measurements reveal a ferromagnetic coupling J=+15.9 and +17.9 cm^?1 between the two Ni^II ions in 2 ClO₄ and 4 BPh₄ (H=?2 JS₁S₂). HF‐ESR measurements yield a negative axial magnetic anisotropy (D<0), which implies a bistable (easy axis) magnetic ground state. The binding of the [Ni₂L(dppba)]ClO₄ complex to gold was ascertained by four complementary surface analytical methods: contact angle measurements, atomic‐force microscopy, X‐ray photoelectron spectroscopy, and spectroscopic ellipsometry. The results indicate that the complexes are attached to the Au surface through coordinative Au? P bonds in a monolayer.     

An Unusual Stable Mononuclear MnIII Bis‐terpyridine Complex Exhibiting Jahn–Teller Compression: Electrochemical Synthesis,Physical Characterisation and Theoretical Study

The mononuclear manganese bis‐terpyridine complex [Mn(tolyl‐terpy)₂](X)₃ ( 1 (X)₃; X=BF₄, ClO₄, PF₆; tolyl‐terpy=4′‐(4‐methylphenyl)‐2,2′:6′,2“‐terpyridine), containing Mn in the unusual +III oxidation state, has been isolated and characterised. The 1 ³⁺ ion is a rare example of a mononuclear Mn^III complex stabilised solely by neutral N ligands. Complex 1 ³⁺ is obtained by electrochemical oxidation of the corresponding Mn^II compound 1 ²⁺ in anhydrous acetonitrile. Under these conditions the cyclic voltammogram of 1 ²⁺ exhibits not only the well‐known Mn^II/Mn^III oxidation at E_1/2=+0.91 V versus Ag/Ag⁺ (+1.21 V vs. SCE) but also a second metal‐based oxidation process corresponding to Mn^III/Mn^IV at E_1/2=+1.63 V (+1.93 V vs. SCE). Single crystals of 1 (PF₆)₃?2 CH₃CN were obtained by an electrocrystallisation procedure. X‐ray analysis unambiguously revealed its tetragonally compressed octahedral geometry and high‐spin character. The electronic properties of 1 ³⁺ were investigated in detail by magnetic measurements and theoretical calculations, from which a D value of +4.82 cm^?1 was precisely determined. Density functional and complete active space self consistent field ab initio calculations both correctly predict a positive sign of D, in agreement with the compressed tetragonal distortion observed in the X‐ray structure of 1 (PF₆)₃?2 CH₃CN. The different contributions to D were calculated, and the results show that 1) the spin–orbit coupling part (+2.593 cm^?1) is predominant compared to the spin–spin interaction (+1.075 cm^?1) and 2) the excited triplet states make the dominant contribution to the total D value.     

Influence of Central Metalloligand Geometry on Electronic Communication between Metals: Syntheses,Crystal Structures,MMCT Properties of Isomeric Cyanido‐Bridged Fe2Ru Complexes,and TDDFT Calculations

To investigate how the central metalloligand geometry influences distant or vicinal metal‐to‐metal charge‐transfer (MMCT) properties of polynuclear complexes, cis‐ and trans‐isomeric heterotrimetallic complexes, and their one‐ and two‐electron oxidation products, cis/trans‐ [Cp(dppe)Fe^IINCRu^II(phen)₂CN‐Fe^II(dppe)Cp][PF₆]₂ (cis/trans‐ 1 [PF₆]₂), cis/trans‐[Cp(dppe)Fe^IINCRu^II(phen)₂CNFe^III‐(dppe)Cp][PF₆]₃ (cis/trans‐ 1 [PF₆]₃) and cis/trans‐[Cp(dppe)Fe^IIINCRu^II(phen)₂CN‐Fe^III(dppe)Cp][PF₆]₄ (cis/trans‐ 1 [PF₆]₄) have been synthesized and characterized. Electrochemical measurements show the presence of electronic interactions between the two external Fe^II atoms of the cis‐ and trans‐isomeric complexes cis/trans‐ 1 [PF₆]₂. The electronic properties of all these complexes were studied and compared by spectroscopic techniques and TDDFT//DFT calculations. As expected, both mixed valence complexes cis/trans‐ 1 [PF₆]₃ exhibited different strong absorption signals in the NIR region, which should mainly be attributed to a transition from an MO that is delocalized over the Ru^II‐CN‐Fe^II subunit to a Fe^III d orbital with some contributions from the co‐ligands. Moreover, the NIR transition energy in trans‐ 1 [PF₆]₃ is lower than that in cis‐ 1 [PF₆]₃, which is related to the symmetry of their molecular orbitals on the basis of the molecular orbital analysis. Also, the electronic spectra of the two‐electron oxidized complexes show that trans‐ 1 [PF₆]₄ possesses lower vicinal Ru^II→Fe^III MMCT transition energy than cis‐ 1 [PF₆]₄. Moreover, the assignment of MMCT transition of the oxidized products and the differences of the electronic properties between the cis and trans complexes can be well rationalized using TDDFT//DFT calculations.     

Diverse Ligand‐Functionalized Mixed‐Valent Hexamanganese Sandwiched Silicotungstates with Single‐Molecule Magnet Behavior

Under hydrothermal conditions, replacement of the water molecules in the [Mn^III₄Mn^II₂O₄(H₂O)₄]⁸⁺ cluster of mixed‐valent Mn₆ sandwiched silicotungstate [(B‐α‐SiW₉O₃₄)₂Mn^III₄Mn^II₂O₄(H₂O)₄]^12? ( 1 a ) with organic N ligands led to the isolation of five organic–inorganic hybrid, Mn₆‐substituted polyoxometalates (POMs) 2 – 6 . They were all structurally characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, diffuse‐reflectance spectroscopy, and powder and single‐crystal X‐ray diffraction. Compounds 2 – 6 represent the first series of mixed‐valent {Mn^III₄Mn^II₂O₄(H₂O)_4?n(L)_n} sandwiched POMs covalently functionalized by organic ligands. The preparation of 1 – 6 not only indicates that the double‐cubane {Mn^III₄Mn^II₂O₄(H₂O)_4?n(L)_n} clusters are very stable fragments in both conventional aqueous solution and hydrothermal systems and that organic functionalization of the [Mn^III₄Mn^II₂O₄(H₂O)₄]⁸⁺ cluster by substitution reactions is feasible, but also demonstrates that hydrothermal environments can promote and facilitate the occurrence of this substitution reaction. This work confirms that hydrothermal synthesis is effective for making novel mixed‐valent POMs substituted with transition‐metal (TM) clusters by combining lacunary Keggin precursors with TM cations and tunable organic ligands. Furthermore, magnetic measurements reveal that 3 and 6 exhibit single‐molecule magnet behavior.     

A New 3D Manganese(II) Coordination Polymer with 4,4‐Dicarboxy‐2,2′‐bipyridine and 1,10‐Phenanthroline: Synthesis,Structural, and Magnetic Properties

A new 3D Mn^II metal‐organic framework compound {Mn(phen)(dcbp)}_n (H₂dcbp = 4,4‐dicarboxy‐2,2′‐bipyridine, phen = 1,10‐phenanthroline) was isolated under hydrothermal conditions and structurally characterized. In the compound, the dcbp ligand is deprotonated to give a neutral species (metal:ligand with 1:1 stoichiometry). Along the c axis, the neighboring Mn^II ions are linked by two carboxylate bridges in µ₂‐coordinating mode to generate a 1D zigzag chain, and these chains are interlinked by dicarboxylate groups of long dcbp ligands to generate a 3D (4,4)‐connected structure with the (4².8⁴) net topology. IR and UV/Vis spectroscopy and variable temperature magnetic susceptibility measurements were made, which indicated weak antiferromagnetic interactions between the Mn^II ions of the compound.     

Insight into D6h Symmetry: Targeting Strong Axiality in Stable Dysprosium(III) Hexagonal Bipyramidal Single‐Ion Magnets

Following a novel synthetic strategy where the strong uniaxial ligand field generated by the Ph₃SiO^? (Ph₃SiO^?=anion of triphenylsilanol) and the 2,4‐di‐^tBu‐PhO^? (2,4‐di‐^tBu‐PhO^?=anion of 2,4‐di‐tertbutylphenol) ligands combined with the weak equatorial field of the ligand L^N6 , leads to [Dy^III(L^N6)(2,4‐di‐^tBu‐PhO)₂](PF₆) ( 1 ), [Dy^III(L^N6)(Ph₃SiO)₂](PF₆) ( 2 ) and [Dy^III(L^N6)(Ph₃SiO)₂](BPh₄) ( 3 ) hexagonal bipyramidal dysprosium(III) single‐molecule magnets (SMMs) with high anisotropy barriers of U_eff=973 K for 1 , U_eff=1080 K for 2 and U_eff=1124 K for 3 under zero applied dc field. Ab initio calculations predict that the dominant magnetization reversal barrier of these complexes expands up to the 3rd Kramers doublet, thus revealing for the first time the exceptional uniaxial magnetic anisotropy that even the six equatorial donor atoms fail to negate, opening up the possibility to other higher‐order symmetry SMMs.     

Mixed‐Valence Nickel Bis(azamacrocycle) Compounds with Ghost‐Leg‐type Sheets

The fabrication of so‐called ghost‐leg sheets and their electronic properties is reported. This unique sheet structure is composed of one‐dimensional mixed‐valence nickel chains, which are linked with one another by bis(azamacrocycle) ligands. They are also topologically unique Ni^II/Ni^III mixed‐valence complexes, as confirmed by X‐ray and optical measurements. Moreover, their magnetic susceptibilities indicated two‐dimensional antiferromagnetic behavior following the Fisher 1D chain model with interchain interactions, where spins on Ni^III sites mutually interact antiferromagnetically in the sheets.     

Chiral Supramolecular Nanotubes of Single‐Chain Magnets

We report a single‐chain magnet (SCM) made of a terbium(III) building block and a nitronyl‐nitroxide radical (NIT) functionalized with an aliphatic chain. This substitution is targeted to induce a long‐range distortion of the polymeric chain and accordingly it gives rise to chains that are curled with almost 20 nm helical pitch. They self‐organize as a chiral tubular superstructure made of 11 chains wound around each other. The supramolecular tubes have a 4.5 nm internal diameter. Overall, this forms a porous chiral network with almost 44 % porosity. Ab initio calculations highlight that each Tb^III ion possesses high magnetic anisotropy. Indeed, notwithstanding the supramolecular arrangement each chain behaves as a SCM. Magnetic relaxation with both finite and infinite‐size regimes is observed and confirms the validity of the Ising approximation. This is associated with quite strong coercive field and magnetic remanence (H_c=2400 Oe M_R=2.09 μ_B at 0.5 K) for this class of compounds.     

Cyano‐bridged Molecular Square: [Ni(iprtacn)Fe(phen)2(CN)2]2(PF6)4·6CH3CN – Preparation,Structure, Magnetic Properties and Binding with DNA

The cyano‐bridged molecular square Ni(iprtacn)]₂[Fe(phen)₂(CN)₂]₂(PF₆)₄ · 6CH₃CN ( 1 ) (iprtacn = 1,4,7‐triisopropyl‐1,4,7‐triazacyclononane, phen = 1, 10‐phenanthroline) was prepared and its crystal structure, magnetic properties, and binding with DNA were characterized. The four metal ions Ni^IIFe^IINi^IIFe^II of the complex 1 are almost coplanar. Magnetic susceptibilities measured over the range of 2–300 K show weak antiferromagnetic interactions between the two nickel(II) ions; best fitting for the experimental data leads to J = –1.27 cm^–1. UV/Vis and fluorescence spectra show that the complex is able to displace DNA‐bound EB and bind to DNA with strong interactions.     

catena‐Poly[[(1,10‐phenanthroline‐κ2N,N′)manganese(II)]‐di‐μ‐salicylato‐κ4O:O′]

In the title polymeric complex, [Mn(C₇H₅O₃)₂(C₁₂H₈N₂)]_n, the Mn^II atom is located on a twofold axis and displays a distorted octa­hedral coordination geometry, formed by four salicylate anions and one 1,10‐phenanthroline (phen) mol­ecule. The salicylate anions doubly bridge the Mn^II atoms to form one‐dimensional polymeric chains. A comparison of Mn—O bond distances with the corresponding Mn—O—C angles suggests a significant electrostatic content in the Mn—O bonds. A face‐to‐face distance of 3.352 (7) Å between neighbouring parallel phen planes indicates π–π stacking inter­actions between polymeric chains.     

White Light Emissive DyIII Single‐Molecule Magnets Sensitized by Diamagnetic [CoIII(CN)6]3− Linkers

The self‐assembly of Dy^III–3‐hydroxypyridine (3‐OHpy) complexes with hexacyanidocobaltate(III) anions in water produces cyanido‐bridged {[Dy^III(3‐OHpy)₂(H₂O)₄] [Co^III(CN)₆]}?H₂O ( 1 ) chains. They reveal a single‐molecule magnet (SMM) behavior with a large zero direct current (dc) field energy barrier, ΔE=266(12) cm^?1 (≈385 K), originating from the single‐ion property of eight‐coordinated Dy^III of an elongated dodecahedral geometry, which are embedded with diamagnetic [Co^III(CN)₆]^3? ions into zig‐zag coordination chains. The SMM character is enhanced by the external dc magnetic field, which results in the ΔE of 320(23) cm^?1 (≈460 K) at H_dc=1 kOe, and the opening of a butterfly hysteresis loop below 6 K. Complex 1 exhibits white Dy^III‐based emission realized by energy transfer from Co^III and 3‐OHpy to Dy^III. Low temperature emission spectra were correlated with SMM property giving the estimation of the zero field ΔE. 1 is a unique example of bifunctional magneto‐luminescent material combining white emission and slow magnetic relaxation with a large energy barrier, both controlled by rich structural and electronic interplay between Dy^III, 3‐OHpy, and [Co^III(CN)₆]^3?.     

A Heterometallic FeII–DyIII Single‐Molecule Magnet with a Record Anisotropy Barrier

A record anisotropy barrier (319 cm^?1) for all d‐f complexes was observed for a unique Fe^II‐Dy^III‐Fe^II single‐molecule magnet (SMM), which possesses two asymmetric and distorted Fe^II ions and one quasi‐D_5h Dy^III ion. The frozen magnetization of the Dy^III ion leads to the decreased Fe^II relaxation rates evident in the Mössbauer spectrum. Ab initio calculations suggest that tunneling is interrupted effectively thanks to the exchange doublets.     

An Unusually Delocalized Mixed‐Valence State of a Cyanidometal‐Bridged Compound Induced by Thermal Electron Transfer

The heterometallic complexes trans ‐[Cp(dppe)FeNCRu(o ‐bpy)CNFe(dppe)Cp][PF₆]_n ( 1 [PF₆]_n , n =2, 3, 4; o ‐bpy=1,2‐bis(2,2′‐bipyridyl‐6‐yl)ethane, dppe=1,2‐bis(diphenylphosphino)ethane, Cp=1,3‐cyclopentadiene) in three distinct states have been synthesized and fully characterized. 1 ³⁺[PF₆]₃ and 1 ⁴⁺[PF₆]₄ are the one‐ and two‐electron oxidation products of 1 ²⁺[PF₆]₂, respectively. The investigated results suggest that 1 [PF₆]₃ is a Class II mixed valence compound. 1 [PF₆]₄ after a thermal treatment at 400 K shows an unusually delocalized mixed valence state of [Fe^III‐NC‐Ru^III‐CN‐Fe^II], which is induced by electron transfer from the central Ru^II to the terminal Fe^III in 1 [PF₆]₄, which was confirmed by IR spectroscopy, magnetic data, and EPR and Mössbauer spectroscopy.     

Developing Intense Blue and Magenta Colors in α‐LiZnBO3: The Role of 3d‐Metal Substitution and Coordination

We describe the synthesis, crystal structures, and optical absorption spectra/colors of 3d‐transition‐metal‐substituted α‐LiZnBO₃ derivatives: α‐LiZn_1?xM^II_xBO₃ (M^II=Co^II (0<x<0.50), Ni^II (0<x≤0.05), Cu^II (0<x≤0.10)) and α‐Li_1+xZn_1?2xM^III_xBO₃ (M^III=Mn^III (0<x≤0.10), Fe^III (0<x≤0.25)). The crystal structure of the host α‐LiZnBO₃, which is both disordered and distorted with respect to Li and Zn occupancies and coordination geometries, is largely retained in the derivatives, which gives rise to unique colors (blue for Co^II, magenta for Ni^II, violet for Cu^II) that could be of significance for the development of new, inexpensive, and environmentally friendly pigment materials, particularly in the case of the blue pigments. Accordingly, this work identifies distorted tetrahedral MO₄ (M=Co, Ni, Cu) structural units, with a long M?O bond that results in trigonal bipyramidal geometry, as new chromophores for blue, magenta, and violet colors in a α‐LiZnBO₃ host. From the L*a*b* color coordinates, we found that Co‐substituted compounds have an intense blue color that is stronger than that of CoAl₂O₄ and YIn_0.90Mn_0.10O₃. The near‐infrared (NIR) reflectance spectral studies indicate that these compounds exhibit a moderate IR reflectivity that could be significant for applications as “cool pigments”.