Two tetranuclear Ni(II) complexes from substituted imidazole dicarboxylates: syntheses,structures, thermal and magnetic properties

Two tetranuclear nickel(II) complexes, [Ni₄ (p-BrPhHIDC)₄(py)₄(H₂O)₄]·CH₃OH (p-BrPhH₃IDC = 2-(p-bromophenyl)-1H-imidazole-4,5-dicarboxylic acid) (1) and [Ni₄(p-ClPhHIDC)₄ (CH₃CN)₄(H₂O)₄]·4H₂O (p-ClPhH₃IDC = 2-(p-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid, py = pyridine) (2), have been solvothermally synthesised and structurally characterised. Both compounds consist of similar tetranuclear Ni(II) cores, in which the imidazole dicarboxylate ligands adopt the similar coordination mode. The thermal properties of 1 and 2 have been investigated. Also, it is discovered that there exists antiferromagnetic coupling between the Ni(II) ions in 1 and 2; the best fittings to the experimental magnetic susceptibilities gave J = ? 9.89 cm^? 1 and g = 2.18 for 1, and J = ? 10.54 cm^? 1 and g = 2.14 for 2.     

Intermolecular Interaction and Magnetic Coupling Mechanism of a Mononuclear Nickel(II) Complex

The mononuclear complex [Ni(HOphen)(OSO₃)(H₂O)₃] · 5H₂O (HOphen = 1, 10‐phenanthrolin‐2‐ol) was prepared and its single structure was determined by X‐ray crystallography. In this complex, the Ni^II ion has a distorted octahedral arrangement. Crystal structure analysis shows that two kinds of π–π stacking interactions and C–H ··· O short contact intermolecular interactions exist among the adjacent complexes. Fitting to the variable‐temperature magnetic susceptibility data gave the magnetic coupling constant, 2J = –0.98 cm^–1. Theoretical calculations, based on density functional theory (DFT) coupling with the broken‐symmetry approach (BS), revealed that the π–π stacking magnetic coupling pathways resulted in weak ferromagnetic interactions with 2J = 4.86 cm^–1 and 2J = 4.16 cm^–1, respectively, for the adjacent Ni^II ions with separations of 8.568(19) Å and 8.749(32) Å, respectively; whereas the magnetic coupling pathway of the C–H ··· O short contact intermolecular interaction led to a weak antiferromagnetic interaction with 2J = –17.62 cm^–1 for the adjacent Ni^II ions with a separation of 10.291(26) Å. The ferromagnetic coupling sign can be explained by the McConnell I spin‐polarization mechanism.     

Field-Induced SMM Behaviour of Tetranuclear Coordination Clusters with a Cubane [Ni4O4] Core

Two tetranuclear Ni(II) complexes: [Ni₄(HL¹)₄] ⋅ H₂O ( 1 ) and [Ni₄(HL²)₄] ⋅ 1.5 dmf ( 2 ) where dmf=dimethylformamide, H₃L¹=4-(tert-butyl)-2-(((2-hydroxy-5-nitrophenyl)imino)methyl)-6-(hydroxymethyl)phenol and H₃L²=4-(tert-butyl)-2-(hydroxymethyl)-6-(((2-hydroxyphenyl)-imino)methyl)phenol, have been prepared and characterized by single crystal X-Ray diffraction, elemental analysis and FT-IR spectroscopy. The solid-state structures reveal the formation of highly symmetric and asymmetric [Ni₄O₄] cubane cores in complexes 1 and 2 , respectively. Extensive magnetic studies show that both complexes present ferromagnetic exchange interactions between the Ni(II) ions within the cubane core with g=2.113(3), J₁=−7.89(8) cm⁻¹, J₂=13.3(1) cm⁻¹ and |D|=11.3(4) cm⁻¹ (for 1 ) and g=2.206(4), J₁=1.0(1) cm⁻¹, J₂=7.8(1) cm⁻¹ and |D|=8.7(2) cm⁻¹ (for 2 ). The large anisotropy, high ground spin state (arising from the ferromagnetic coupling) and the good isolation of the clusters provided by the Schiff base ligands, give rise to the first examples of field-induced single-molecule magnets (FI−SMM) in Ni₄O₄ clusters and to the highest energy barrier reported to date in a Ni₄O₄ cluster.     

Solvent effects on the dimensionality of oxamato-bridged manganese(II) compounds

Abstract

Two new oxamate-containing manganese(II) complexes, [{Mn(H₂edpba)(H₂O)₂}₂]_n (1) and [Mn(H₂edpba)(dmso)₂]?dmso?CH₃COCH₃?H₂O (2) (H₄edpba = N,N′-ethylenediphenylenebis(oxamic acid) and dmso = dimethylsulfoxide), have been synthesized and the structures of 1 and 2 were characterized by single crystal X-ray diffraction. The structure of 1 consists of neutral honeycomb networks in which each manganese(II) is six-coordinate by one H₂edpba^2? ligand and two carboxylate–oxygens from two other H₂edpba^2? ligands building the equatorial plane. Each manganese is connected to its nearest neighbor through two carboxylate(monoprotonated oxamate) bridges in an anti-syn conformation. A dmso solution of single crystals of 1 was placed under acetone atmosphere affording 2, whereas putting 2 in equimolar water:ethanol mixture results in 1. The molecular structure of 2 is made up of mononuclear manganese(II) units which are interlinked by weak C–H?π and edge-to-face π-stacking interactions leading to supramolecular chains along the crystallographic b axis. Magnetic measurements reveal the occurrence of an antiferromagnetic coupling between two manganese(II) ions through anti-syn carboxylate bridges for 1 [J = ?1.18 cm^?1, the Hamiltonian being defined as H = ?J S₁^.S₂] and very weak intrachain ferromagnetic interactions in 2 [J = + 0.046 cm^?1, H = ?J ∑_iS_i^.S_i + 1].     

Crystal structure of tetraphenylarsonium aquatetracyanonitridorhenate(V), (AsPh4)2 [ReN(H2O)(CN)4]·5H2O

The crystal structure of (AsPh₄)₂[ReN(H₂O)(CN)₄]·5H₂O has been determined from three-dimensional X-ray diffraction data. The yellow crystals are monoclinic, space group P2₁/n with cell dimensionsa=15.482(1),b=19.950(2),c=16.999(1)? and β=101.69(6)^o,Z=4,D _expt=1.48(1)g cm⁻³ andD _calc=1.52g cm⁻³. The anisotropic refinement of 7858 observed reflections converged toR=0.055. The [ReN(H₂O)(CN)₄]²⁻ ion has a distorted octahedral geometry. Bond distances: Re≡N=1.639(8), Re−OH₂=2.496(7) and Re−C_(av)=2.11(1) ?. The rhenium atom is displaced by 0.35 ? out of the plane formed by the four carbon atoms of the cyano ligands towards the terminal nitrido ligand. TMC 2479     

Structural diversity for three Zn(II) coordination polymers from 4-nitrobenzene-1,2-dicarboxylate and bispyridyl ligand

Three Zn(II) complexes, [Zn₂(bpp)₂(FNA)₂]·H₂O (1), [Zn(bpp)(FNA)]·H₂O (2), and Zn₂(bpp)₂(FNA)₂ (3) (bpp = 1,3-bi(4-pyridyl)propane, H₂FNA = 4-nitrobenzene-1,2-dicarboxylic acid), were synthesized and characterized by single-crystal and powder X-ray diffraction methods, IR spectroscopy, TG analyses, elemental analyses, and fluorescent analysis. In 1, the Zn(II) ions are linked by FNA anions and bpp into 2-D layers. The Zn(II) ions in 2 are bridged by FNA anions into chiral chains, which are interlinked by bpp into 3-D metal–organic framework with (6⁵·8) CdS topology. Complex 3 features 1-D zigzag chains, which are interconnected by bpp ligands to give a 3-D framework with (6·7⁴·8)(6⁴·7·8) topology. Complexes 2 and 3 exhibit significant ferroelectric behavior (for 2 remnant polarization Pr = 0.050 μC cm^?2, coercive field Ec = 1.13 kV cm^?1, saturation of the spontaneous polarization Ps = 0.239 μC cm^?2; for 3 Pr = 0.192 μC cm^?2, Ec = 4.64 kV cm^?1, Ps = 0.298 μC cm^?2).     

Magnetic Properties of a Single‐Molecule Lanthanide–Transition‐Metal Compound Containing 52 Gadolinium and 56 Nickel Atoms

Monodisperse metal clusters provide a unique platform for investigating magnetic exchange within molecular magnets. Herein, the core–shell structure of the monodisperse molecule magnet of [Gd₅₂Ni₅₆(IDA)₄₈(OH)₁₅₄(H₂O)₃₈]@SiO₂ ( 1 a @SiO₂) was prepared by encapsulating one high‐nuclearity lanthanide–transition‐metal compound of [Gd₅₂Ni₅₆(IDA)₄₈(OH)₁₅₄(H₂O)₃₈]?(NO₃)₁₈?164 H₂O ( 1 ) (IDA=iminodiacetate) into one silica nanosphere through a facile one‐pot microemulsion method. 1 a @SiO₂ was characterized using transmission electron microscopy, N₂ adsorption–desorption isotherms, and inductively coupled plasma‐atomic emission spectrometry. Magnetic investigation of 1 and 1 a revealed J₁=0.25 cm^?1, J₂=?0.060 cm^?1, J₃=?0.22 cm^?1, J₄=?8.63 cm^?1, g=1.95, and z J=?2.0×10^?3 cm^?1 for 1 , and J₁=0.26 cm^?1, J₂=?0.065 cm^?1, J₃=?0.23 cm^?1, J₄=?8.40 cm^?1 g=1.99, and z J=0.000 cm^?1 for 1 a @SiO₂. The z J=0 in 1 a @SiO₂ suggests that weak antiferromagnetic coupling between the compounds is shielded by silica nanospheres.     

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.     

Mono-, di-, and trinuclear phosphonate oxygen-bridged copper(II) complexes: syntheses,structures, and properties

Reactions of copper salts, zoledronic acid, and 2,2′-bipyridine/1,10-phenanthroline in aqueous ethanolic solutions afforded four phosphonate oxygen-bridged copper complexes, Cu(bipy)(H₄zdn)(HSO₄) (1), [Cu₂(bipy)₂(H₂zdn)(H₂O)(Cl)]·4H₂O (2), [Cu₂(phen)₂(H₂zdn)(H₂O)(Cl)]·2.5H₂O (3), and [Cu₃(bipy)₃(H₄zdn)(H₂zdn)(SO₄)]·5H₂O (4) (H₅zdn = zoledronic acid, bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline). The copper centers of 1–4 have square pyramidal coordination geometries. The Cu(II) ions are coordinated to bipy/phen, zoledronate, and HSO₄^?/Cl^? forming mononuclear units for 1, dinuclear for 2 and 3, and trinuclear for 4. These building units are further extended into 3-D supramolecular networks via multiple hydrogen bond interactions. Temperature-dependent magnetic properties of 2 and 4 suggest weak antiferromagnetic coupling (J = ?4.53(8) cm^?1 for 2, J = ?1.69(4) cm^?1 for 4). The antitumor activity of 2 was evaluated against the human lung cancer cell line and indicates effective time- and dose-dependent cytotoxic effects.     

Structure and properties of an oxalato-bridged dinickel(II) complex with a tetraazamacrocycle bearing an aminomethyl pendant arm, 5-aminomethyl-5R(S),12R(S)-dimethyl-1,4,8,11-tetraazacyclotetradecane

The oxalato-bridged dinickel(II) complex with the title ligand, [Ni₂(L ^a H)₂(μ-ox)](ClO₄)₂·2H₂O (1), was prepared and its structure was determined by X-ray crystallography, as well as that of the monomeric nickel(II) complex, [Ni(L ^a H)ox]ClO₄·3H₂O (2). In Complexes 1 and 2, the ligand, L ^a , is folded along the N(4)–Ni(1)–N(11) axis. The antiferromagnetic coupling between the two nickel(II) centers in 1 was revealed and the coupling constant, J?=??17.4?cm^?1, and g?=?2.11 were estimated. It was found that the oxalato-bridged dimer 1 was readily converted to the mononuclear cis-nickel(II) complex [NiL ^a (OH₂)](ClO₄)₂ (3a), in basic aqueous solution. In [NiL ^a (CH₃CN)]I₂ (3b), which was derived from 3a, the aminomethyl pendant arm is coordinated to the Ni(II) ion and L ^a is folded along the N(1)–Ni(1)–N(8) axis.     

Cyanide-bridged one-dimensional bimetallic complexes based on a tridentate copper(II) building block: synthesis,crystal structures and magnetic properties

The reactions of [M^III(CN)₆]^3? (M = Cr or Co) with Cu^II complexes of a tridentate schiff base [Cu(aemp)Cl] or [Cu(aemp)Ac]₂ (Haemp = 2-[(2-amino-ethylimino)-methyl]-phenol) give rise to 1D cyanide-bridged bimetallic coordination polymers [Cu₄(aemp)₄(H₂O)₂][Cr(CN)₆]Cl (1) and [Cu₃(aemp)₃(H₂O)][Co(CN)₆]·2H₂O·MeOH (2). In complex 1, the six cyanide ligands of the [Cr(CN)₆]^3? moiety are involved in bridging, while in complex 2 only five cyanide ligands act as bridges to give a neutral chain. Magnetic studies reveal that complex 1 exhibits intermetallic ferromagnetic coupling, with J = 8.2 cm^?1.     

(H2teta)2{[Ni(teta)][Fe(CN)6]2}•17H2O (teta＝5,7,7,12,14,14-Hexa-methyl-1,4,8,11-tetraazacyclotetradecane)超分子化合物的合成、晶体结构和磁性质研究

将Ni(teta)(ClO₄)₂ (teta＝5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)的DMF溶液和K₃[Fe(CN)₆]的水溶液在填充了琼脂冻胶的U型管中通过扩散反应, 得到了标题化合物(H₂teta)₂{[Ni(teta)][Fe(CN)₆]₂}•17H₂O, 该化合物晶体属三斜晶系, 空间群P1, 晶胞参数为a＝0.9998(2) nm, b＝1.5514(3) nm, c＝1.6647(4) nm, α＝114.15(2)°, β＝100.91(2)°, γ＝93.42(2)°, V＝2.2863(10) nm³, z＝1, D_c＝1.196 g•cm^－3, F(000)＝890, μ＝5.84 cm^－1, GOF＝0.894, R₁＝0.0582, wR₂＝0.1446 [I＞2σ(I)]. 该化合物的基本单元由2个[H₂teta]^2＋阳离子、1个{[Ni(teta)][Fe(CN)₆]₂}^4－阴离子和17个水分子组成, 它们之间通过N—H…N氢键而形成具有二维平面结构的超分子化合物. 1.8～300 K变温磁化率研究表明, 化合物中三核体系Fe (s＝1/2)-Ni (s＝1)-Fe (s＝1/2)中心原子间通过氰基桥联而发生强的铁磁相互作用, 磁参数J＝4.33 cm^－1, g＝2.6, θ＝60 K. 通过TG-DTG测定了配合物的热稳定性.     

Three different bonding modes of cyano groups in the coordination polymer [Cu(en)2(H2O)][Cu(en)2Ni2Cu2(CN)10]·2H2O (en is 1,2‐diaminoethane)

Partial reduction of the Cu^II ions in the aqueous system Cu^II–en–[Ni(CN)₄]^2? (1/1/1) (en is 1,2‐di­amino­ethane) yields a novel heterobimetallic mixed‐valence compound, poly­[[aqua­bis(1,2‐di­amino­ethane)copper(II)] [hexa‐μ‐cyano‐tetra­cyano­bis(1,2‐di­amino­ethane)­tricopper(I,II)­dinickel(II)] dihydrate], [Cu(C₂H₈N₂)₂(H₂O)][Ni₂Cu₃(CN)₁₀(C₂H₈N₂)₂]·2H₂O or [Cu(en)₂(H₂O)][Cu(en)₂Ni₂Cu₂(CN)₁₀]·2H₂O. The structure is formed by a negatively charged two‐dimensional array of the cyano complex [Cu(en)₂Ni₂Cu₂(CN)₁₀]_n^2n?, [Cu(en)₂(H₂O)]²⁺ complex cations and water mol­ecules of crystallization. These last are involved in a complicated hydrogen‐bonding system. The cyano groups act as terminal, μ₂‐bridging or μ₃‐bridging ligands.     

Syntheses,structures, and host-guest interactions of 2-D grid-type cyanide-bridged compounds [Zn(L)(H2O)2][M(CN)4]·3H2O (L = N,N′-bis(4-pyridylformamide)-1,4-benzene; M = Ni,Pd or Pt)

Self-assembly of Zn²⁺, the pillar ligand N,N′-bis(4-pyridylformamide)-1,4-benzene, and [M(CN)₄]^2? (M = Ni, Pd, or Pt) formed three compounds [Zn(L)(H₂O)₂][M(CN)₄]·3H₂O (1–3). Single-crystal X-ray diffraction (XRD) analysis reveals that 1–3 are isostructural and consist of cyanide-bridged 2-D grid-type layers built of [Zn(L)(H₂O)₂]²⁺ chains cross-linked by [M(CN)₄]^2? units. Thermogravimetric and powder XRD analyses indicate that 1 has a high thermal stability and exhibits reversibility for desorption/resorption of water guest molecules.     

Synthesis and structural characterization of mono- and dinuclear NiII and PdII complexes derived from tetradentate 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene

The reaction of Schiff base 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene (L) with either NiCl₂·6H₂O or [Pd^IICl₂(CH₃CN)₂]/Na[BF₄] in 1?:?1 stoichiometry yielded mononuclear ionic complexes, trans-[Ni^II(L)(H₂O)₂]Cl₂·3H₂O (1·3H₂O) and [Pd^II(L)][BF₄]₂ (2), respectively; the reaction of L with [Pd^IICl₂(CH₃CN)₂] in 1?:?2 ratio yielded dinuclear cis-[Pd^II ₂(μ-L)Cl₄] (3). Complexes 1–3 were characterized by vibrational spectroscopy and X-ray diffraction; diamagnetic 2 and 3 were also characterized by NMR in solution. The molecular structures of 1 and 2 displayed tetradentate coordination of L with formation of two five-membered and one six-membered chelate rings for both complexes. In 3, L showed bidentate coordination mode for each pyridylimine toward Pd^II. Complex 1 has distorted octahedral geometry around Ni^II and an extended hydrogen-bond network; distorted square planar geometry around Pd^II in 2 and 3 was observed.     

A 1-D alternating copper(II) chain based on three acetate-bridging modes: synthesis,crystal structure,DNA binding and magnetic properties

A new 1-D alternating copper(II) polymer, [Cu₂(L)(OAc)₄]_n (1) (L = 5-chloro-2-(pyridine-2-yl)benzo[d]thiazole), has been isolated and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, and magnetic susceptibility. The complex crystallized in the triclinic space group P-1, a = 8.2277(16) Å, b = 9.4233(19) Å, c = 15.831(3) Å, α = 103.38(3)°, β = 99.95(3)°, γ = 92.70(3)°, V = 1171.3(4) Å³, and comprises a 1-D polymer linked by three kinds of acetate-bridging modes in an alternating manner. UV–visible and fluorescence spectra revealed that 1 is bound to CT-DNA in a partial intercalation mode. Through gel electrophoresis assays, 1 displayed an efficient oxidative cleavage activity on supercoiled plasmid DNA (pUC19) in the presence of H₂O₂. Magnetic measurements were performed from 2 to 300 K, and the experimental results were satisfactorily reproduced with J₁ = –160 ± 20 cm^?1, J₂ = 5.8 ± 0.2 cm^?1, zJ′ = 0.381 ± 0.005 cm^?1 and g = 2.1, showing antiferromagnetic coupling between Cu1 and Cu1i, ferromagnetic exchange between Cu2 and Cu2ii, and a weak ferromagnetic molecular field correction accounting for all interspecies interactions.     

Syntheses,crystal structures,and magnetic properties of a series of double end-on azido-bridged dinuclear manganese(II) complexes

Four azido-bridged dinuclear Mn(II) complexes, [Mn₂(phen)₄ μ-₁,₁-N₃)₂][Fe^III(bpmb)(CN)₂]₂·H₂O (1), [Mn₂(phen)₄(μ-₁,₁-N₃)₂][Fe^III(bpClb)(CN)₂]₂·H₂O (2), and [Mn₂(phen)₄(μ-₁,₁-N₃)₂][M^III(bpdmb)(CN)₂]₂·3H₂O [M = Fe (3) or Cr (4); phen = 1,10-phenanthroline, bpmb^2– = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate, bpClb^2– = 1,2-bis(pyridine-2-carboxamido) 4-chloro-benzenate, bpdmb^2– = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate], have been synthesized using the synthetic strategy of large anion inducement. Single-crystal X-ray diffraction analysis reveals that all four complexes are doubly end-on (EO) azido-bridged binuclear Mn(II) complexes with two large [M(L)(CN)₂]^– (L = bpmb^2?, bpClb^2?, or bpdmb^2?) building blocks acting as charge-compensating anions. The magnetic properties of the complexes have been investigated, and the results indicate that the magnetic coupling between two Mn(II) centers through the EO azide bridges is ferromagnetic, with J = 0.64(1) cm^?1 for 1, 0.43(1) cm^?1 for 2, 0.50(1) cm^?1 for 3, and 0.66(2) cm^?1 for 4. The magneto-structural relationships of EO azido-bridged Mn(II) systems are discussed.     

Charakterisierung von Distorsionsisomeren der Anionen Pentacyano-oxo-molybdat(IV) sowie Tetracyano-oxo-aqua-molybdat(IV) im festen Zustand. Kristallstrukturen von [(C6H5)4P]3[MoO(CN)5] · 7 H2O(grün), [(C6H5)4As]2 [MoO(OH2)(CN)4] · 4 H2O (blau) und [(C6H5)4P]2[MoO(OH2)(CN)4] · 4 H2O (grün)

Characterization of Distortional Isomers of the Anions Pentacyano-oxo-molybdate(IV) and of Tetracyano-aqua-oxo-molybdate(IV) in the Solid State. Crystal Structures of [(C₆H₅)₄P]₃[MoO(CN)₅] · 7 H₂O (green), [(C₆H₅)₄As]₂[MoO(OH₂)(CN)₄] · 4 H₂O (blue), and [(C₆H₅)₄P]₂[MoO(OH₂) (CN)₄] · 4 H₂O (green) Preparation of a series of salts containing the new pentacyano-oxo-molybdate(IV) anion is described: Cs₂H[MoO(CN)₅] (blue), [(CH₃)₄N]₂H[MoO(CN)₅] · 2 H₂O (blue) and [Cr(en)₃] [MoO(CN)₅] · 4 H₂O (green). The green [(C₆H₅)₄P]₃[MoO(CN)₅] · 7 H₂O crystallizes triclinic in the space group P1 . The molybdenum(IV) center is in an pseudo-octahedral environment of a terminal oxo-group (d(Mo?O); 1.705(4) Å), a CN^? group in the trans-position (d(Mo? C): 2.373(6) Å), and four equatorial CN^? groups (averaged d(Mo? C): 2.178 (Å). The blue and green salts exhibit v(Mo?O) stretching frequencies at 948 cm^?1 and 920 cm^?1, respectively. Blue and green salts containing the [MoO(OH₂)(CN)₄]^2? anion and [(C₆H₅)₄P]⁺ or [(C₆H₅)₄As]⁺ cations have been prepared and characterized by single crystal crystallography. [(C₆H₅)₄P]₂[MoO(OH₂)(CN)₄] · 4 H₂O (green) and [(C₆H₅)₄As]₂[MoO(OH₂)(CN)₄] · 4 H₂O (blue) crystallize monoclinic in the space group C—P2₁/n. They are considered to be distortional isomers of the complex anion: the green species has a Mo?O bond distance of 1.72(2) Å whereas for the blue species d(Mo?O) = 1.60(2) Å is found; the corresponding v(Mo?O) frequencies are at 920 cm^?1 and 980 cm^?1.     

IV Dodekaedrische [Mo(CN)8]‐Koordination in den cyanoverbrückten Cobalt‐ und Nickel‐Amminkomplexen MII2(NH3)8[Mo(CN)8] · 1,5 H2O (MII = Co,Ni) und Ni2(NH3)9[Mo(CN)8] · 2 H2O

Crystal Structures of Octacyanomolybdates(IV). IV Dodecahedral [Mo(CN)₈] Coordination of the Cyano‐Bridged Cobalt and Nickel Ammin Complexes M^II₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (M^II = Co, Ni) and Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O At single crystals of the hydrated cyano complexes Co₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 910.0(4), b = 1671(2), c = 1501(1) pm, β = 93.76(6)°) and Ni₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 899.9(9), b = 1654.7(4), c = 1488(1) pm, β = 94.01°), isostructurally crystallizing in space group P2₁/c, Z = 4, and of trigonal Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O (a = 955.1(1), c = 2326.7(7) pm, P3₁, Z = 3), X‐ray structure determinations were performed at 168 resp. 153 K. The [Mo(CN)₈]^4– groups of the three compounds, prepared at about 275 K and easily decomposing, show but slightly distorted dodecahedral coordination (mean distances Mo–C: 216.3, 215.4 and 216.1 pm). Within the monoclinic complexes the anions twodimensionally form cyano bridges to the ammin cations [M(NH₃)₄]²⁺ and are connected with the resulting [MN₆] octahedra (Co–N: 215.1 pm, Ni–N: 209.8 pm) into strongly puckered layers. The trigonal complex exhibits a chain structure, as one [Ni(NH₃)₅]²⁺ cation is only bound as terminal octahedron (Ni–N: 212.0 pm). Details and the influence of hydrogen bridges are discussed.     

Synthesis,crystal structures,and magnetic properties of three K[M(bpb)(CN)2]-based trinuclear sandwich-like heterobimetallic M(III)–Ni(II) (M = Fe,Cr, Co) complexes

Three trinuclear sandwich-type cyanide-bridged M^III–Ni^II complexes, {[Ni(cyclm)[Fe(bpb)(CN)₂]₂}·8H₂O (1), {[Ni(cyclm)[Cr(bpb)(CN)₂]₂}·2H₂O (2), and {[Ni(cyclm)[Co(bpb)(CN)₂]₂}·CH₃OH·2H₂O (3) (cyclm?=?1,4,8,11-tetraazacyclotetradecane), have been synthesized using K[M(bpb)(CN)₂] (M?=?Fe, Cr, Co; bpb?=?1,2-bis(pyridine-2-carboxamido)benzenate) as building block and one Ni(II) compound containing a 14-membered macrocycle ring as assembling segment. All the complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray structure determination. Single X-ray diffraction analysis shows similar sandwich-like structures, in which the two cyanide-containing building blocks are monodentate through one of their two cyanides, coordinated face to face to the central Ni(II). Investigation of the magnetic properties of 1 and 2 reveals ferromagnetic magnetic coupling between the neighboring Fe(III)/Cr(III) and Ni(II) through the bridging cyanide. A best-fit to the magnetic susceptibilities of 1 and 2 based on the trinuclear M₂Ni model leads to magnetic coupling constants J?=?5.47(1)?cm^?1 for 1 and J?=?6.37(2)?cm^?1 for 2.