Synthesis,crystal structure and magnetic properties of a two‐dimensional cyanide‐based heterometallic coordination polymer with cationic piperazinium ligands: poly[aquatetra‐μ2‐cyanido‐κ8C:N‐dicyanido‐κ2C‐(piperazinium‐κN4)cobalt(III)copper(II)]

Cyanide as a bridge can be used to construct homo‐ and heterometallic complexes with intriguing structures and interesting magnetic properties. These ligands can generate diverse structures, including clusters, one‐dimensional chains, two‐dimensional layers and three‐dimensional frameworks. The title cyanide‐bridged Cu^II–Co^III heterometallic compound, [Cu^IICo^III(CN)₆(C₄H₁₁N₂)(H₂O)]_n, has been synthesized and characterized by single‐crystal X‐ray diffraction analysis, magnetic measurement, thermal study, vibrational spectroscopy (FT–IR) and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (SEM–EDS). The crystal structure analysis revealed that it has a two‐dimensional grid‐like structure built up of [Cu(Hpip)(H₂O)]³⁺ cations (Hpip is piperazinium) and [Co(CN)₆]³⁻ anions that are linked through bridging cyanide ligands. The overall three‐dimensional supramolecular network is expanded by a combination of interlayer O—H...N and N—H...O hydrogen bonds involving the coordinated water molecules and the N atoms of the nonbridging cyanide groups and monodentate cationic piperazinium ligands. A magnetic investigation shows that antiferromagnetic interactions exist in the title compound.     

Poly[tetraamminecopper(II) bis[tris(μ2‐cyanido‐κ2C,N)dicuprate(I)]]: a unique CuI–CuII mixed‐valence complex containing anionic cuprous cyanide layers and [Cu(NH3)4]2+ cations

The title compound, {[Cu(NH₃)₄][Cu(CN)₃]₂}_n, features a Cu^I–Cu^II mixed‐valence CuCN framework based on {[Cu₂(CN)₃]⁻}_n anionic layers and [Cu(NH₃)₄]²⁺ cations. The asymmetric unit contains two different Cu^I ions and one Cu^II ion which lies on a centre of inversion. Each Cu^I ion is coordinated to three cyanide ligands with a distorted trigonal–planar geometry, while the Cu^II ion is ligated by four ammine ligands, with a distorted square‐planar coordination geometry. The interlinkage between Cu^I ions and cyanide bridges produces a honeycomb‐like {[Cu₂(CN)₃]⁻}_n anionic layer containing 18‐membered planar [Cu(CN)]₆ metallocycles. A [Cu(NH₃)₄]²⁺ cation fills each metallocyclic cavity within pairs of exactly superimposed {[Cu₂(CN)₃]⁻}_n anionic layers, but there are no cations between the layers of adjacent pairs, which are offset. Pairs of N—H...N hydrogen‐bonding interactions link the N—H groups of the ammine ligands to the N atoms of cyanide ligands.     

Synthesis,Structure and Magnetic Properties of a Cyano‐bridged Dinuclear Compound fac‐{[FeIII(pzTp)(CN)2(μ‐CN)] CuII(TPyA)}·Et2O·ClO4 (pzTp = tetrakis(pyrazolyl)borate)

The reaction of tricyanometallate precursor, (Bu₄N)[(pzTp)Fe(CN)₃] with Cu(ClO₄)₂·6H₂O in the presence of the tetradentate ligand tris(2‐pyridylmethyl)amine (TPyA) afford the dinuclear compound fac‐{[Fe^III(pzTp)(CN)₂(μ‐CN)]Cu^II(TPA)}·Et₂O·ClO₄ ( 1 ) (pzTp = tetrakis(pyrazolyl)borate). The molecular structure was determined by single‐crystal X‐ray diffraction. In compound 1 , the Fe^III ion is coordinated by three cyanide carbon atoms and three nitrogen atoms of pzTp anions. Whereas, the Cu^II ion is surrounded by one cyanide nitrogen atom and four nitrogen atoms from the TPyA ligand. Magnetic measurements indicate the intramolecular ferromagnetic coupling is observed for compound 1 , and it has S = 1 ground states.     

The three‐dimensional coordination network in poly[di‐μ3‐cyanido‐μ5‐[5‐(pyridin‐4‐yl)tetrazolato]‐tricopper(I)]

In the title three‐dimensional tetrazolate‐based coordination polymer, poly[bis(μ₃‐cyanido‐κ³N:C:C)[μ₅‐5‐(pyridin‐4‐yl)tetrazolato‐κ⁵N:N′:N′′:N′′′:N′′′′]tricopper(I)], [Cu₃(C₆H₄N₅)(CN)₂]_n, there are two types of coordinated Cu^I atoms. One type exhibits a tetrahedral environment and the other, residing on a twofold axis, adopts a trigonal coordination environment. The closest Cu...Cu distance is only 2.531 (2) Å, involving a bridging cyanide C atom. All four tetrazolate and the pyridine N atom of the 4‐(pyridin‐4‐yl)‐1H‐tetrazolate anion are coordinated to these Cu^I atoms and exhibit a μ₅‐bridging mode. The three‐dimensional coordination network can be topologically simplified as a rarely observed (3,3,4,5)‐connected network with the Schläfli symbol (4.6.8⁴)₂.(4².6.8⁷).(6.8²)₃.     

catena‐Poly­[[[1,8‐bis(2‐hydroxy­ethyl)‐1,3,6,8,10,13‐hexa­aza­cyclo­tetra­decane]copper(II)]‐μ‐cyano‐[tri­cyano­nitro­soiron(III)]‐μ‐cyano]

The bimetallic title complex, [CuFe(CN)₅(C₁₂H₃₀N₆O₂)(NO)] or [Cu(L)Fe(CN)₅(NO)] [where L is 1,8‐bis(2‐hydroxy­ethyl)‐1,3,6,8,10,13‐hexa­aza­cyclo­tetra­decane], has a one‐dimensional zigzag polymeric –Cu(L)–NC–Fe(NO)(CN)₃–CN–Cu(L)– chain, in which the Cu^II and Fe^II centres are linked by two CN groups. In the complex, the Cu^II ion is coordinated by four N atoms from the L ligand [Cu—N(L) = 1.999 (2)–2.016 (2) Å] and two cyanide N atoms [Cu—N = 2.383 (2) and 2.902 (3) Å], and has an elongated octahedral geometry. The Fe^II centre is in a distorted octahedral environment, with Fe—N(nitroso) = 1.656 (2) Å and Fe—C(CN) = 1.938 (3)–1.948 (3) Å. The one‐dimensional zigzag chains are linked to form a three‐dimensional network via N—H⋯N and O—H⋯N hydrogen bonds.     

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.     

Diamond‐ and Graphite‐Like Octacyanometalate‐Based Polymers Induced by Metal Ions

By using cyclohexane‐1,2‐diamine (chxn), Ni(ClO₄)₂ ? 6H₂O and Na₃[Mo(CN)₈] ? 4H₂O, a 3D diamond‐like polymer {[Ni^II(chxn)₂]₂[Mo^IV(CN)₈] ? 8H₂O}_n ( 1 ) was synthesised, whereas the reaction of chxn and Cu(ClO₄)₂ ? 6H₂O with Na₃[M^V(CN)₈] ? 4H₂O (M=Mo, W) afforded two isomorphous graphite‐like complexes {[Cu^II(chxn)₂]₃[Mo^V(CN)₈]₂ ? 2H₂O}_n ( 2 ) and {[Cu^II(chxn)₂]₃[W^V(CN)₈]₂ ? 2H₂O}_n ( 3 ). When the same synthetic procedure was employed, but replacing Na₃[Mo(CN)₈] ? 4H₂O by (Bu₃NH)₃[Mo(CN)₈] ? 4H₂O (Bu₃N=tributylamine), {[Cu^II(chxn)₂Mo^IV(CN)₈][Cu^II(chxn)₂] ? 2H₂O}_n ( 4 ) was obtained. Single‐crystal X‐ray diffraction analyses showed that the framework of 4 is similar to 2 and 3 , except that a discrete [Cu(chxn)₂]²⁺ moiety in 4 possesses large channels of parallel adjacent layers. The experimental results showed that in this system, the diamond‐ or graphite‐like framework was strongly influenced by the inducement of metal ions. The magnetic properties illustrate that the diamagnetic [Mo^IV(CN)₈] bridges mediate very weak antiferromagnetic coupling between the Ni^II ions in 1 , but lead to the paramagnetic behaviour in 4 because [Mo^IV(CN)₈] weakly coordinates to the Cu^II ions. The magnetic investigations of 2 and 3 indicate the presence of ferromagnetic coupling between the Cu^II and W^V/Mo^V ions, and the more diffuse 5d orbitals lead to a stronger magnetic coupling interaction between the W^V and Cu^II ions than between the Mo^V and Cu^II ions.     

Poly[diaqua(μ‐4,4′‐bipyridine‐κ2N:N′)bis(μ‐cyanido‐κ2C:N)bis(cyanido‐κC)nickel(II)copper(II)]: a metal–organic cyanide‐bridged framework

The structure of the title compound, [NiCu(CN)₄(C₁₀H₈N₂)(H₂O)₂]_n or [{Cu(H₂O)₂}(μ‐C₁₀H₈N₂)(μ‐CN)₂{Ni(CN)₂}]_n, was shown to be a metal–organic cyanide‐bridged framework, composed essentially of –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains (4,4′‐bpy is 4,4′‐bipyridine) linked by [Ni(CN)₄]²⁻ anions. Both metal atoms sit on special positions; the Cu^II atom occupies an inversion center, while the Ni^II atom of the cyanometallate sits on a twofold axis. The 4,4′‐bpy ligand is also situated about a center of symmetry, located at the center of the bridging C—C bond. The scientific impact of this structure lies in the unique manner in which the framework is built up. The arrangement of the –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains, which are mutually perpendicular and non‐intersecting, creates large channels running parallel to the c axis. Within these channels, the [Ni(CN)₄]²⁻ anions coordinate to successive Cu^II atoms, forming zigzag –Cu—N[triple‐bond]C—Ni—C[triple‐bond]N—Cu– chains. In this manner, a three‐dimensional framework structure is constructed. To the authors' knowledge, this arrangement has not been observed in any of the many copper(II)–4,4′‐bipyridine framework complexes synthesized to date. The coordination environment of the Cu^II atom is completed by two water molecules. The framework is further strengthened by O—H...N hydrogen bonds involving the water molecules and the symmetry‐equivalent nonbridging cyanide N atoms.     

Cyanide-bridged [Fe8M6] clusters displaying single-molecule magnetism (M=Ni) and electron-transfer-coupled spin transitions (M=Co)

Cyanide‐bridged metal complexes of [Fe₈M₆(μ‐CN)₁₄(CN)₁₀ (tp)₈(HL)₁₀(CH₃CN)₂][PF₆]₄?n CH₃CN?m H₂O (HL=3‐(2‐pyridyl)‐5‐[4‐(diphenylamino)phenyl]‐1H‐pyrazole), tp^?=hydrotris(pyrazolylborate), 1 : M=Ni with n=11 and m=7, and 2 : M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2₁/n. They have tetradecanuclear cores composed of eight low‐spin (LS) Fe^III and six high‐spin (HS) M^II ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown‐like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro‐ and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2 , respectively. Ac magnetic susceptibility measurements of 1 showed frequency‐dependent in‐ and out‐of‐phase signals, characteristic of single‐molecule magnetism (SMM), while desolvated samples of 2 showed thermal‐ and photoinduced intramolecular electron‐transfer‐coupled spin transition (ETCST) between the [(LS‐Fe^II)₃(LS‐Fe^III)₅(HS‐Co^II)₃(LS‐Co^III)₃] and the [(LS‐Fe^III)₈(HS‐Co^II)₆] states.     

Poly[deca‐μ2‐cyanido‐dicyanidobis(μ2‐ethylenediamine)bis(ethylenediamine)tricadmium(II)dicobalt(III)]: a two‐dimensional coordination polymer

The title coordination polymer, [Cd₃Co₂(CN)₁₂(C₂H₈N₂)₄]_n, has an infinite two‐dimensional network structure. The asymmetric unit is composed of two crystallographically independent Cd^II atoms, one of which is located on a twofold rotation axis. There are two independent ethylenediamine (en) ligands, one of which bis‐chelates to the Cd atom that sits in a general position, while the other bridges this Cd atom to that sitting on the twofold axis. The Cd atom located on the twofold rotation axis is linked to four equivalent Co^III atoms via cyanide bridges, while the Cd atom that sits in a general position is connected to three equivalent Co^III atoms via cyanide bridges. In this way, a series of trinuclear, tetranuclear and pentanuclear macrocycles are linked to form a two‐dimensional network structure lying parallel to the bc plane. In the crystal structure, these two‐dimensional networks are linked via N—H...N hydrogen bonds involving an en NH₂ H atom and a cyanide N atom, leading to the formation of a three‐dimensional structure. This coordination polymer is only the second example involving a cyanometallate where the en ligand is present in both chelating and bridging coordination modes.     

Copper(II) and cadmium(II) isothiocyanate coordination polymers with 4,4′‐bi‐1,2,4‐triazole

The coordination polymers catena‐poly[[[(4,4′‐bi‐1,2,4‐triazole‐κN¹)bis(thiocyanato‐κN)copper(II)]‐μ‐4,4′‐bi‐1,2,4‐triazole‐κ²N¹:N^1′] dihydrate], {[Cu(NCS)₂(C₄H₄N₆)₂]·2H₂O}_n, (I), and poly[tetrakis(μ‐4,4′‐bi‐1,2,4‐triazole‐κ²N¹:N^1′)bis(μ‐thiocyanato‐κ²N:S)tetrakis(thiocyanato‐κN)tricadmium(II)], [Cd₃(NCS)₆(C₄H₄N₆)₄]_n, (II), exhibit chain and two‐dimensional layer structures, respectively. The differentiation of the Lewis acidic nature of Cu^II and Cd^II has an influence on the coordination modes of the triazole and thiocyanate ligands, leading to topologically different polymeric motifs. In (I), copper ions are linked by bitriazole N:N′‐bridges into zigzag chains and the tetragonal–pyramidal CuN₅ environment is composed of two thiocyanate N atoms and three triazole N atoms [basal Cu—N = 1.9530 (18)–2.0390 (14) Å and apical Cu—N = 2.2637 (15) Å]. The structure of (II) contains two types of crystallographically unique Cd^II atoms. One type lies on an inversion center in a distorted CdN₆ octahedral environment, with bitriazole ligands in the equatorial plane and terminal isothiocyanate N atoms in the axial positions. The other type lies on a general position and forms centrosymmetric binuclear [Cd₂(μ‐NCS‐κ²N:S)₂(NCS)₂] units (tetragonal–pyramidal CdN₄S coordination). N:N′‐Bridging bitriazole ligands link the Cd centers into a flat (4,4)‐network.     

A cyanide‐bridged heterometallic coordination polymer constructed from square‐planar [Ni(CN)4]2−: synthesis,crystal structure,thermal decomposition,electron paramagnetic resonance (EPR) spectrum and magnetic properties

Square‐planar complexes are commonly formed by transition metal ions having a d⁸ electron configuration. Planar cyanometallate anions have been used extensively as design elements in supramolecular coordination systems. In particular, square‐planar tetracyanometallate(II) ions, i.e. [M(CN)₄]²⁻ (M^II = Ni, Pd or Pt), are used as good building blocks for bimetallic Hofmann‐type assemblies and their analogues. Square‐planar tetracyanonickellate(II) complexes have been extensively developed with N‐donor groups as additional co‐ligands, but studies of these systems using O‐donor ligands are scarce. A new cyanide‐bridged Cu^II–Ni^II heterometallic compound, poly[[diaquatetra‐μ₂‐cyanido‐κ⁸C:N‐nickel(II)copper(II)] monohydrate], {[Cu^IINi^II(CN)₄(H₂O)₂]·H₂O}_n, has been synthesized and characterized by X‐ray single‐crystal diffraction analyses, vibrational spectroscopy (FT–IR), thermal analysis, electron paramagnetic resonance (EPR) and magnetic moment measurements. The structural analysis revealed that it has a two‐dimensional grid‐like structure built up of cationic [Cu(H₂O)₂]²⁺ and anionic [Ni(CN)₄]²⁻ units connected through bridging cyanide ligands. The overall three‐dimensional supramolecular network is expanded by a combination of interlayer O—H…N and intralayer O—H…O hydrogen‐bond interactions. The first decomposition reactions take place at 335 K under a static air atmosphere, which illustrates the existence of guest water molecules in the interlayer spaces. The electron paramagnetic resonance (EPR) spectrum confirms that the Cu^II cation has an axial coordination symmetry and that the unpaired electrons occupy the d orbital. In addition, magnetic investigations showed that antiferromagnetic interactions exist in the Cu^II atoms through the diamagnetic [Ni(CN)₄]²⁻ ion.     

Cyano‐bridged extended heteronuclear supramolecular architectures with hexacyano­cobalt(III) as building blocks

The cyano‐bridged heteronuclear coordination polymer poly[tris[(5,12‐dimethyl‐7,14‐diphenyl‐1,4,8,11‐tetraazacyclo­tetra­deca‐4,11‐diene)copper(II)]‐hexa‐μ‐cyano‐bis[tricyano­cobalt(III)] di­methyl­formamide solvate trihydrate], {[Cu₃Co₂(CN)₁₂(C₂₄H₃₂N₄)₃]·C₃H₇NO·3H₂O}_n, was synthesized by the assembly reaction of [CuL]²⁺ (L is 5,12‐dimethyl‐7,14‐di­phenyl‐1,4,8,11‐tetraazacyclotetradeca‐4,11‐diene) and [Co(CN)₆]³⁻ in a dimethyl­formamide–water solution. The structure consists of neutral cyano‐bridged Cu₃Co₂ units with the unique Co atom in a general position and all three Cu atoms on independent inversion centres. Each [Co(CN)₆]³⁻ ion connects three Cu^II ions via three cyano groups to form a novel cyano‐bridged two‐dimensional stair‐shaped‐layer structure. The water and dimethyl­formamide molecules are situated in the inter‐fragment spaces.     

Two different one‐dimensional structural motifs in [catena‐{Cu(tacn)}2Pd(CN)4]Br2·[catena‐Cu(tacn)Pd(CN)4]2·H2O (tacn is 1,4,7‐triazacyclononane)

The title compound, catena‐poly[[bis[(triazacyclononane‐κ³N,N′,N′′)copper(II)]‐di‐μ‐cyanido‐κ⁴N:C‐palladate(II)‐di‐μ‐cyanido‐κ⁴C:N] dibromide bis[[(triazacyclononane‐κ³N,N′,N′′)copper(II)]‐μ‐cyanido‐κ²N:C‐[dicyanidopalladate(II)]‐μ‐cyanido‐κ²C:N] monohydrate], {[Cu₂Pd(CN)₄(C₆H₁₅N₃)₂]Br₂·[Cu₂Pd₂(CN)₈(C₆H₁₅N₃)₂]·H₂O}_n, (I), was isolated from an aqueous solution containing tacn·3HBr (tacn is 1,4,7‐triazacyclononane), Cu²⁺ and tetracyanidopalladate(2−) anions. The crystal structure of (I) is essentially ionic and built up of 2,2‐electroneutral chains, viz. [Cu(tacn)(NC)–Pd(CN)₂–(CN)–], positively charged 2,4‐ribbons exhibiting the composition {[Cu(tacn)(NC)₂–Pd(CN)₂–Cu(tacn)]²ⁿ⁺}_n, bromide anions and one disordered water molecule of crystallization. The O atom of the water molecule occupies two unique crystallographic positions, one on a centre of symmetry, which is half occupied, and the other in a general position with one‐quarter occupancy. One of the tacn ligands also exhibits disorder. The formation of two different types of one‐dimensional structural motif within the same structure is a unique feature of this compound.     

A cyanide‐bridged FeII–NdIII bimetallic assembly with a one‐dimensional ladder‐like chain structure

The title complex, catena‐poly[[[(2,2′‐bipyridine‐1κ²N,N′)tris(methanol‐2κO)(nitrato‐2κ²O,O′)‐μ‐cyanido‐1:2C:N‐cyanido‐1κC‐iron(II)neodymium(III)]‐di‐μ‐cyanido‐1:2′C:N;2:1′N:C] methanol solvate], {[Fe^IINd^III(CN)₄(NO₃)(C₁₀H₈N₂)(CH₃OH)₃]·CH₃OH}_n, is made up of ladder‐like one‐dimensional chains oriented along the c axis. Each ladder consists of two strands based on alternating Fe^II and Nd^III centers connected by cyanide bridges. Furthermore, two such parallel chains are connected by additional cyanide cross‐pieces (the `rungs' of the ladder), which likewise connect Fe^II and Nd^III centers, such that each [Fe(CN)₄(bipy)]²⁻ unit (bipy is 2,2′‐bipyridine) coordinates with three Nd^III centers and each Nd^III center connects with three different [Fe(CN)₄(bipy)]²⁻ units. In the complex, the iron(II) cation is six‐coordinated with a distorted octahedral geometry and the neodymium(III) cation is eight‐coordinated with a distorted dodecahedral environment.     

Redox‐Assisted Self‐Assembly of a Water‐Soluble Cyanido‐Bridged Mixed Valence {CoIII/FeII}2 Square

The facile redox‐assisted assembly of a water‐soluble, extremely robust, cyanide‐bridged mixed‐valence [{Co^III{(Me)₂(μ‐ET)cyclen}}₂{(μ‐NC)₂Fe^II(CN)₄}₂]^2? square is reported. The preparation process involved the use of the enhanced lability of inert Co^III synthons triggered by outer‐sphere redox processes. Characterization of the final compounds has been carried out by NMR, UV/Vis, electrochemistry, and ICP analyses. DFT calculations have been conducted to optimize a structure that has the same hydrodynamic radius as that obtained from DOSY experiments. The new compound is extremely robust, surviving in aqueous solution within the 0–12 pH range for months. The species shows a high affinity for both protons and hydroxo ions in aqueous medium.     

Mono‐ and dinuclear CuII complexes of the benzyldipicolylamine (BDPA) ligand: crystal structure,synthesis and characterization

The crystal structures of mono‐ and dinuclear Cu^II trifluoromethanesulfonate (triflate) complexes with benzyldipicolylamine (BDPA) are described. From equimolar amounts of Cu(triflate)₂ and BDPA, a water‐bound Cu^II mononuclear complex, aqua(benzyldipicolylamine‐κ³N ,N′ ,N ′′)bis(trifluoromethanesulfonato‐κO )copper(II) tetrahydrofuran monosolvate, [Cu(CF₃SO₃)₂(C₁₉H₁₉N₃)(H₂O)]·C₄H₈O, (I), and a triflate‐bridged Cu^II dinuclear complex, bis(μ‐trifluoromethanesulfonato‐κ²O :O ′)bis[(benzyldipicolylamine‐κ³N ,N′ ,N ′′)(trifluoromethanesulfonato‐κO )copper(II)], [Cu₂(CF₃SO₃)₄(C₁₉H₁₉N₃)₂], were synthesized. The presence of residual moisture in the reaction medium afforded water‐bound complex (I), whereas dinuclear complex (II) was synthesized from an anhydrous reaction medium. Single‐crystal X‐ray structure analysis reveals that the Cu^II centres adopt slightly distorted octahedral geometries in both complexes. The metal‐bound water molecule in (I) is involved in intermolecular O—H…O hydrogen bonds with triflate ligands and tetrahydrofuran solvent molecules. In (II), weak intermolecular C—H…F(triflate) and C—H…O(triflate) hydrogen bonds stabilize the crystal lattice. Complexes (I) and (II) were also characterized fully using FT–IR and UV–Vis spectroscopy, cyclic voltammetry and elemental analysis.     

A Mixed‐Valence {Fe13} Cluster Exhibiting Metal‐to‐Metal Charge‐Transfer‐Switched Spin Crossover

It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal‐to‐metal charge transfer (MMCT) and spin‐crossover (SCO) to tune the valence and spin states of metal ions. Herein, a metallocyanate building block is used to link with a Fe^II‐triazole moiety and generates a mixed‐valence complex {[(Tp^4‐Me)Fe^III(CN)₃]₉[Fe^II₄(trz‐ph)₆]}?[Ph₃PMe]₂?[(Tp^4‐Me)Fe^III(CN)₃] ( 1 ; trz‐ph=4‐phenyl‐4H‐1,2,4‐triazole). Moreover, MMCT occurs between Fe^III and one of the Fe^II sites after heat treatment, resulting in the generation of a new phase, {[(Tp^4‐Me)Fe^II(CN)₃][(Tp^4‐Me)Fe^III(CN)₃]₈ [Fe^IIIFe^II₃(trz‐ph)₆]}? [Ph₃PMe]₂?[(Tp^4‐Me)Fe^III(CN)₃] ( 1 a ). Structural and magnetic studies reveal that MMCT can tune the two‐step SCO behavior of 1 into one‐step SCO behavior of 1 a . Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin‐transition materials with accessible multi‐electronic states.     

Copper(I) and Gold(I) Complexes with N,N′‐Bis(diphenylphosphino)‐2,6‐diaminopyridine as Ligand: Synthesis and Molecular Structures

Reaction of CuI with 1 or 2 equivalent(s) N,N′‐Bis(diphenylphosphino)‐2,6‐diaminopyridine (BDDP) gives two different complexes, [Cu(I)μ‐(BDDP‐κP,N_py)]₂ ( 1 ) and [Cu(BDDP‐κP,N_py)₂]I ( 2 ), in high yields. The determination of the molecular structure show that both Cu^I atoms are tetrahedrally coordinated, rather than a square‐planar geometry reported for Cr⁰, Ni^II‐BDDP complexes before, which contains a planar tridentate chelate ring system. The introduction of AuCl(tht) (tht = tetrahydrothiophene) into [Cu(BDDP‐κP,N_py)₂]I leads unexpectedly to the formation of a digold complex 2,6‐[(ClAuPh₂P)HN]₂C₅H₃N and dimeric [Cu(I)μ‐(BDDP‐κP,N_py)]₂.