Synthesis, crystal structures, and magnetic properties of a new family of heterometallic cyanide-bridged Fe(III)2M(II)2 (M=Mn, Ni, and Co) square complexes

New heterobimetallic tetranuclear complexes of formula [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Mn(II)(bpy)(2)](2)(ClO(4))(2)·CH(3)CN (1), [Fe(III){HB(pz)(3)}(CN)(2)(μ-CN)Ni(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (2a), [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Ni(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (2b), [Fe(III){HB(pz)(3)}(CN)(2)(μ-CN)Co(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (3a), and [Fe(III){B(pz)(4)}(CN)(2)(μ-CN)Co(II)(dmphen)(2)](2)(ClO(4))(2)·2CH(3)OH (3b), [HB(pz)(3)(-) = hydrotris(1-pyrazolyl)borate, B(Pz)(4)(-) = tetrakis(1-pyrazolyl)borate, dmphen = 2,9-dimethyl-1,10-phenanthroline, bpy = 2,2'-bipyridine] have been synthesized and structurally and magnetically characterized. Complexes 1-3b have been prepared by following a rational route based on the self-assembly of the tricyanometalate precursor fac-[Fe(III)(L)(CN)(3)](-) (L = tridentate anionic ligand) and cationic preformed complexes [M(II)(L')(2)(H(2)O)(2)](2+) (L' = bidentate α-diimine type ligand), this last species having four blocked coordination sites and two labile ones located in cis positions. The structures of 1-3b consist of cationic tetranuclear Fe(III)(2)M(II)(2) square complexes [M = Mn (1), Ni (2a and 2b), Co (3a and 3b)] where corners are defined by the metal ions and the edges by the Fe-CN-M units. The charge is balanced by free perchlorate anions. The [Fe(L)(CN)(3)](-) complex in 1-3b acts as a ligand through two cyanide groups toward two divalent metal complexes. The magnetic properties of 1-3b have been investigated in the temperature range 2-300 K. A moderately strong antiferromagnetic interaction between the low-spin Fe(III) (S = 1/2) and high-spin Mn(II) (S = 5/2) ions has been found for 1 leading to an S = 4 ground state (J(1) = -6.2 and J(2) = -2.7 cm(-1)), whereas a moderately strong ferromagnetic interaction between the low-spin Fe(III) (S = 1/2) and high-spin Ni(II) (S = 1) and Co(II) (S = 3/2) ions has been found for complexes 2a-3b with S = 3 (2a and 2b) and S = 4 (3a and 3b) ground spin states [J(1) = +21.4 cm(-1) and J(2) = +19.4 cm(-1) (2a); J(1) = +17.0 cm(-1) and J(2) = +12.5 cm(-1) (2b); J(1) = +5.4 cm(-1) and J(2) = +11.1 cm(-1) (3a); J(1) = +8.1 cm(-1) and J(2) = +11.0 cm(-1) (3b)] [the exchange Hamiltonian being of the type H? = -J(S?(i)·S?(j))]. Density functional theory (DFT) calculations have been used to substantiate the nature and magnitude of the exchange magnetic coupling observed in 1-3b and also to analyze the dependence of the exchange magnetic coupling on the structural parameters of the Fe-C-N-M skeleton.     

Heterotrimetallic oxalato-bridged ReIV2MII complexes (M=Mn, Co, Ni, Cu): synthesis, crystal structure, and magnetic properties

The use of the (NBu4)2[ReIVCl4(ox)] mononuclear species as a ligand toward divalent first row transition metal ions in the presence of imidazole affords the new trinuclear compounds of formula (NBu4)2[{ReIVCl4(mu-ox)}2MII(Him)2] [NBu4+=tetra-n-butylammonium cation, ox=oxalate dianion, Him=imidazole; M=Mn (1), Co (2), Ni (3), Cu (4)] whose preparation, crystal structures, and magnetic properties are reported. 1-4 are isostructural complexes which are made up of discrete trinuclear [{ReIVCl4(mu-ox)}2MII(Him)2]2- anions and bulky NBu4+ cations. The Re and M atoms exhibit somewhat distorted octahedral surroundings which are built by four chloro and two oxalate oxygens (Re) and two imidazole nitrogen and four oxalate oxygen atoms (M), the central M atom being linked to the two peripheral Re atoms through bis-bidentate oxalate. The values of the Re...M separation across bridging oxalate vary in the range 5.646(2) (M=Ni) to 5.794(2) A (M=Mn). Magnetic susceptibility measurements on polycrystalline samples of 1-4 in the temperature range 1.9-300 K show the occurrence of significant intramolecular antiferro- (1) and ferromagnetic (2-4) interactions. The nature and magnitude of the magnetic coupling in 1-4 are qualitatively understood through orbital symmetry considerations.     

Electronic structures of superconductors YBa2Cu3−x M x O y (M=Sn,Ni)

Based on the EHMO approach, the energy band structures for superconductors YBa₂Cu_3–x Sn _x O _y (y>7) and YBa₂Cu_3–x Ni _x O_y (y<7) were calulated in the present paper. The influence of the cation doping at the Cu site in the unit cell and the oxygen content on their electronic structures was studied. The results showed that the cation doping at the Cu site resulted in the great decreases in the bandwidths of the broad anisotropic Cu-O bands and the densities of states. In YBa₂Cu_3–x Sn _x O _y , however, these decreases are compensated by the increase in the oxygen content caused by the Sn-doping, which results in a small change in the total densities of states. For YBa₂Cu_3–x Ni _x O _y , the effect of the doping on its electronic structures in dominant. The Ni-doping, therefore, results in a great change in the electronic structures. In addition, the study on the projected densities of states of the Ni-doped system revealed that the 2D Cu-O planes in the Y-Ba-Cu-O system played a dominant role in superconductivity.     

Syntheses, X-ray crystal structures, and magnetic properties of novel linear M2[II]U[IV] complexes (M=Co, Ni, Cu, Zn)

Attempts to prepare heterobimetallic complexes in which 3d and uranium magnetic ions are associated by means of the Schiff bases H(2)L(i) derived from 2-hydroxybenzaldehyde or 2-hydroxy-3-methoxybenzaldehyde were unsuccessful because of ligand transfer reactions between [ML(i)] (M=Co, Ni, Cu) and UCl(4) that led to the mononuclear Schiff base complexes of uranium [UL(i)Cl(2)]. The crystal structure of [UL(3)Cl(2)(py)(2)] [L(3)=N,N'-bis(3-methoxysalicylidene)-ethylenediamine; py=pyridine] was determined. The hexadentate Schiff base ligand N,N'-bis(3-hydroxysalicylidene)-2,2-dimethyl-1,3-propanediamine (L) was useful for the synthesis of novel trinuclear complexes of the general formula [[ML(py)](2)U] (M=Co, Ni, Zn) or [[CuL(py)]M'[CuL]] (M'=U, Th, Zr) by reaction of [M(H(2)L)] with [M'(acac)(4)] (acac=MeCOCHCOMe). The crystal structures of the Co(2)U, Ni(2)U, Zn(2)U, Cu(2)U, and Cu(2)Th complexes show that the two ML fragments are orthogonal, being linked to the central actinide ion by the two pairs of oxygen atoms of the Schiff base ligand. In each compound, the UO(8) core exhibits the same dodecahedral geometry, and the three metals are linear. The magnetic study indicated that the two Cu(2+) ions are not coupled in the Cu(2)Zr and Cu(2)Th compounds. The magnetic behavior of the Co(2)U, Ni(2)U, and Cu(2)U complexes was compared with that of the Zn(2)U derivative, in which the paramagnetic 3d ion was replaced with the diamagnetic Zn(2+) ion. A weak antiferromagnetic coupling was observed between the Ni(2+) and the U(4+) ions, while a ferromagnetic interaction was revealed between the Cu(2+) and U(4+) ions.     

Synthesis,properties and crystal structures of R[MIII(bdt)2] complexes (M = Ni,Co, Cu)

New nickel, cobalt and copper complexes with benzene-1,2-dithiole (bdt), of general formula R[M(bdt)₂]: M = Ni, Co and Cu; R = Me₄N, Et₄N, Pr₄N, Me₃PhN, MePh₃P, Ph₄P have been synthesized and characterized by standard physico-chemical methods (elemental analyses, magnetochemical and conductivity measurements, i.r. and u.v.–;vis. spectroscopy). X-ray structural analysis of (MePh₃P)[M(bdt)₂], M = Ni, Co and Cu, confirms that the MS₄ chromophore lies in a slightly distorted square coordination arrangement around the central atom. The three complexes have also been studied by cyclic voltammetry.     

Synthesis, crystal structures and spectroscopic properties of two novel oxamido-bridged trinuclear complexes [Cu2M] (M = Cu, Zn)

Based on the complex ligand CuL (H₂L = 2,3-dioxo-5,6:14,15-dibenzo-7,13-diphenyl-1,4,8,12-tetraazacyclo-pentadeca-7,13-diene), two novel oxamido-bridged trinuclear complexes have been prepared. They are of the formula Cu(CuL)₂(ClO₄)₂ · 4C₂H₅OH (1) and [(CuL)₂Zn(C₂H₅OH)₂](ClO₄)₂ · 2C₂H₅OH (2). The crystal structures of the two complexes have been determined by X-ray crystallography. In complex (1), the central Cu is in a complete square-planar environment, bonding to four oxygen atoms of the oxamido macrocyclic ligand, while in complex (2), the Zn center is six-coordinate in an octahedral geometry, the four oxygen donors from macrocyclic ligand form the basal plane and the axial positions are occupied by other oxygen atoms from C₂H₅OH molecules. The spectroscopic properties have been investigated and the EPR spectra have been simulated by WINEPR and SimFonia programs.     

Two novel heterometallic Cu(II)-Sr(II) coordination polymers based on 3,5-pyrazoledicarboxylic acid: synthesis, crystal structures and magnetic properties

The syntheses, crystal structures and magnetic properties are described for two novel 2D heterometallic Cu(II)-Sr(II) coordination polymers {Sr(H(2)O)(6)[(Im)(4)Cu(4)(pdc)(4)Sr(H(2)O)(4)]·6H(2)O}(n) (1) and [Cu(2)(H(2)O)(2)(pdc)(2)Sr(H(2)O)(3)](n) (2) (H(3)pdc = 3,5-pyrazoledicarboxylic acid; Im = imidazole). The 1 : 1 : 1 : 5 reaction of SrCl(2)·6H(2)O, Cu(NO(3))(2)·3H(2)O, H(3)pdc and imidazole in H(2)O-EtOH at 120 °C under autogenous pressure gave 1. Complex 2 was obtained from the 1 : 1 : 1 H(3)pdc/Sr(OH)(2)·8H(2)O/Cu(NO(3))(2)·3H(2)O reaction mixture in H(2)O-EtOH under solvothermal conditions. Complex 1 can be described as a 2D grid-shaped network with the four Cu(II) ions in a saddle-like conformation. In complex 2, Sr(II) ions link metalloligands [Cu(2)(pdc)(2)(H(2)O)(2)](2-) to generate a 2D layer framework. Variable-temperature solid-state dc magnetic susceptibility studies have been performed in the temperature range 2.0-300 K for complexes 1 and 2. Antiferromagnetic Cu(II)···Cu(II) exchange interactions were found for both 1 and 2.     

Three-dimensional 3d-4f heterometallic coordination polymers: synthesis, structures, and magnetic properties

Three new 3d-4f heterometallic coordination polymers, [Ln(2)(H(2)O)(4)M(2)(H(2)O)(2)(QA)(5)].nH(2)O (H(2)QA = quinolinic acid; Ln = Gd, M = Ni, n = 7 (1); Ln = Gd, M = Co, n = 6.5 (2); Ln = Dy, M = Co, n = 6.5 (3)), have been synthesized through hydrothermal pretreatment and cooling-down crystallization. These compounds possess the isostructural 3D frameworks with 1D chairlike channels along the c axis, which are occupied by noncoordinating water molecules. Crystal data: for 1, C(35)H(41)Gd(2)Ni(2)N(5)O(33), orthorhombic, space group Pna2(1), with a = 28.567(6) A, b = 14.498(3) A, c = 12.250(2) A, and Z = 4; for 2, C(35)H(40)Gd(2)Co(2)N(5)O(32.5), orthorhombic, space group Pna2(1), with a = 28.843(3) A, b = 14.4325(13) A, c = 12.2275(9) A, and Z = 4; for 3, C(35)H(40)Dy(2)Co(2)N(5)O(32.5), orthorhombic, space group Pna2(1), with a = 28.8471(14) A, b = 14.4534(10) A, c = 12.2520(7) A, and Z = 4. The magnetic behaviors for the three compounds have been investigated.     

Cyanide-bridged complexes based on dinuclear Cu(II)-M(II) [M = Pb and Cu] building blocks: Synthesis, crystal structures and magnetic properties

Four cyanide-bridged heterometallic complexes {[CuPb(L 1 )][Fe III (bpb)(CN) 2 ]} 2 ·(ClO 4 ) 2 ·2H 2 O·2CH 3 CN (1), {[CuPb(L 1 )] 2 [Fe II (CN) 6 ](H 2 O) 2 }·10H 2 O (2), {[Cu 2 (L 2 )][Fe III (bpb)(CN) 2 ] 2 }·2H 2 O·2CH 3 OH (3) and {[Cu 2 (L 2 )] 3 [Fe III (CN) 6 ] 2 (H 2 O) 2 }·10H 2 O (4) have been synthesized by treating K[Fe III (bpb)(CN) 2 ] [bpb 2-=1,2-bis(pyridine-2-carboxamido)benzenate] and K 3 [Fe III (CN)] 6 with dinuclear compartmental macrocyclic Schiff-base complexes [CuPb(L 1 )] (ClO 4 ) 2 or [Cu 2 (L 2 )]·(ClO 4 ) 2 , in which H 2 L 1 was derived from 2,6-diformyl-4-methyl-phenol, ethylenediamine, and diethylenetriamine in the molar ratio of 2:1:1 and H 2 L 2 from 2,6-diformyl-4-methyl-phenol and propylenediamine in the molar ratio of 1:1. Single crystal X-ray diffraction analysis reveals that compound 1 displays a cyclic hexanuclear heterotrimetallic molecular structure with alternating [FeⅢ (bpb)(CN) 2 ]- and [CuPb(L 1 )] 2+ units. Complex 2 is of a neutral dumb-bell-type pentanuclear molecular configuration consisting of one [Fe(CN)6] 4- anion sandwiched in two [CuPu(L 1 )] 2+ cations, and the pentanuclear moieties are further connected by the hydrogen bonding to give a 2D supramolecular framework. Heterobimetallic complex 3 is a tetranuclear molecule composed of a centrosymmetric [Cu 2 (L2)] 2+ segment and two terminal cyanide-containing blocks [FeⅢ (bpb)(CN)2 ]- . Octanuclear compound 4 is built from two [Fe(CN)6]3- anions sandwiched in the three [Cu 2 L 2 ] 2+ cations. Investigation of their magnetic properties reveals the overall antiferromagnetic behavior in the series of complexes except 2.     

Hydrothermal syntheses,crystal structures,and properties of two-dimensional homo- and heterometallic cyanide-bridged complexes: [Cu2(CN)2(bpym)] and [Fe(bipy)2(CN)4Cu2] (bpym = 2,2'-bipyrimidine,bipy = 2,2'-bipyridine)

The hydrothermal reaction of K(3)[Fe(CN)(6)], CuCl(2), and 2,2'-bipyridine (bipy) resulted in the formation of a 2D cyanide-bridged heterobimetallic Fe(II)-Cu(I) complex, [Fe(bipy)(2)(CN)(4)Cu(2)], 1. Working in the same conditions, but using 2,2'-bipyrimidine (bpym) instead of bipy and methanol as solvent, we obtained the homometallic Cu(I) complex [Cu(2)(CN)(2)(bpym)](2), 2. The structure of 1 consists of cyanide-bridged Fe(II)-Cu(I) layers, constructed from alternately fused 6 (Fe(2)Cu(4)) and 10 (Fe(2)Cu(8)) metal-membered centrosymmetric rings, in which copper(I) and iron(II) ions exhibit distorted trigonal planar and octahedral cooordination environments, respectively. The formation of 1 can be explained by assuming that, under high pressure and temperature, iron(III) and copper(II) ions are reduced with the simultaneous and/or subsequent substitution of four cyanide ligands by two bipy molecules in the ferricyanide anions. It is interesting to note that 1 is the first cyanide-bridged heterobimetallic complex prepared by solvothermal methods. The structure of 2 consists of neutral 2D honeycomb layers constructed from fused Cu(6)(CN)(4)(bpym)(2) rings, in which copper(I) atoms exhibit distorted tetrahedral geometry. The isolation of 1 and 2, by using K(3)[Fe(CN)(6)] as starting material, demonstrates that hydrothermal chemistry can be used not only to prepare homometallic materials but also to prepare cyanide-bridged bimetallic materials. The temperature dependence of chi(M)T and M?ssbauer measurements for 1 reveal the existence of a high spin <--> low spin equilibrium involving the Fe(II) ions.     

Syntheses,crystal structures,and magnetic properties of 1-D coordination polymers

Three coordination polymers of Robson-type macrocycles, {[Cu₄L¹(4,4′-bipy)₂]·4ClO₄·H₂O}_∞ (1), {[Cu₄L²(4,4′-bipy)₄]·2CH₃CN·4ClO₄·2H₂O}_∞ (2), and {[Zn₂L²(4,4′-bipy)₂]·(ClO₄)₂}_∞ (3) (where H₂L¹ and H₂L² are the [2?+?2] condensation products of 1,3-diaminopropane with 2,6-diformyl-4-methylphenol and 2,6-diformyl-4-fluorophenol, respectively), have been synthesized and characterized. Magnetic susceptibility was measured for 1 and 2 from 2 to 300?K. The optimized magnetic data were J?=?–368.5?cm^?1, J′?=?40.5?cm^?1 with R?=?1.69?×?10^?6 for 1 and J?=?–291.22?cm^?1, J′?=?83.74?cm^?1, ρ = 0.00168 with R?=?1.8?×?10^?11 for 2, respectively. The data reveal strong antiferromagnetic interactions between two Cu(II) ions in the macrocyclic unit and ferromagnetic interaction between the Cu(II) ions in two adjacent macrocyclic units for 1 and 2.     

Structural and magnetic studies on cyano-bridged rectangular Fe2M2 (M = Cu, Ni) clusters

Using the tricyano precursor, (Bu4N)[(Tp)Fe(CN)3] (Tp = Tris(pyrazolyl) hydroborate) (1), four new tetranuclear clusters, [(Tp)Fe(CN)3Cu(Tp)]2.2H2O (2), [(Tp)Fe(CN)3Cu(bpca)]2.4H2O (3) (bpca = bis(2-pyridylcarbonyl)amidate anion), [(Tp)Fe(CN)3Ni(tren)]2(ClO4)2.2H2O (4) (tren = tris(2-amino)ethylamine), and [(Tp)Fe(CN)3Ni(bipy)2]2[(Tp)Fe(CN)3]2.6H2O (5) (bipy = 2,2'-bipyridine), have been synthesized and structurally characterized. The four clusters possess similar square structures, where FeIII and MII (M = CuII or NiII) ions alternate at the rectangle corners. There exist intermolecular - stacking interactions through pyrazolyl groups of Tp- ligands in complexes 2 and 4, which lead to 1D chain structures. Complex 5 shows a 3D network structure through the coexistence of - stacking effects and hydrogen-bonding interactions. Magnetic studies show intramolecular ferromagnetic interactions in all four clusters. The exchange parameters are +11.91 and +1.38 cm(-1) for clusters 2 and 3, respectively, while uniaxial molecular anisotropy can be detected in complex 3 due to the distorted core in its molecular structure. Complex 4 has a ground state of S = 3 and shows SMM behavior with an effective energy barrier of U = 18.9 cm(-1). Unusual spin-glass-like dynamic relaxations are observed for complex 5.     

18-冠-6与Na2[M(mnt)2](M=Cu,Ni)配合物的合成与结构

研究了18-冠-6分别与Na2[M(mnt)2][M=Cu,Ni;mnt=丁二腈烯二硫醇阴离子,C2S2(CN)^2^-~2]的反应,得到的配合物{[Na(18-C-6)][Na(18-C-6)(H2O)]}[Cu(mnt)2](1),[Na(18-C-6)(H2O)]2[Ni(mnt)2].(18-C-6)(2)通过元素分析、红外光谱、X射线单晶衍射进行了表征。两个配合物均为三斜晶系,空间群P1。1的晶体学结构数据：a=1.22697(19)nm,b=1.22780(19)nm,c=1.5665(3)nm,α=95.083(3)°,β=101.534(3)°,Υ=91.007(3)°,V=2.3016(6)nm^3,Z=2,Dcalcd=1.350g/cm^3,F(000)=976,R1=0.0726,wR2=0.1843.2的晶体学结构数据：a=1.11620(17)nm,b=1.22054(18)nm,c=1.27939(18)nm,α=111.647(2)°,β=29.792(3)°,Υ=103.201(2)°,V=2.5461(4)nm^3,Z=1,Dcalcd=1.304g/cm^3,F(000)=642,R1=0.0459,wR2=0.1003.1中的[Cu(mnt)2]^2^-通过mnt的氮原子与[Na(18-C-6)]^+中的钠原子成键,形成了一维链状结构;[Na(18-C-6)(H2O)]^+只起平衡电荷的作用。2中的[Ni(mnt)2]^2^-也通过配体的mnt氮原子与两个[Na(18-C-6)(H2O)]^+中的钠原子成键,形成稳定的中性配合物。     

Syntheses, structures, and magnetic analyses of a family of heterometallic hexanuclear [Ni4M2] (M = Gd, Dy, Y) compounds: observation of slow magnetic relaxation in the Dy(III) derivative

We described the syntheses, crystal structures, and magnetic behavior of a novel series of heterometallic [Ni(4)M(2)] [M = Gd (1), Dy (2) and Y (3)] hexanuclear compounds afforded by the reaction of rare-earth(III) nitrate, nickel(II) acetate, and Schiff-base ligand 2-(2-hydroxy-3-methoxybenzylideneamino)phenol (H(2)L) in a mixture of ethanol and dichloromethane in the presence of triethylamine. Single-crystal X-ray diffraction measurements reveal that all three compounds have a metal core made up of two Ni(2)MO(4) defective cubanes. The magnetic properties of all compounds have been studied. Solid-state direct-current magnetic susceptibility analyses demonstrate competing antiferromagnetic and ferromagnetic interactions within both compounds 1 and 3. Solid-state alternating-current magnetic susceptibility investigations show a frequency-dependent out-of-phase signal for compound 2 below 4 K, suggestive of slow magnetic relaxation.     

Binuclear heterometallic {M-Ln} pivalate complexes (M = Co, Ni, Cu; Ln = Sm, Gd): synthesis, structure, and thermolysis

Binuclear heterometallic complexes (??²-bpy)CoLn(Piv)₅(H₂O), (??²-bpy)NiLn(Piv)₅(H₂O), and (??²-bpy)CuLn(Piv)₅(HPiv) (Ln = Sm or Gd, Piv- is the pivalate anion) were synthesized. A comparative study of the structural characteristics and the thermolysis of the resulting compounds was performed.     

New heterometallic coordination polymers based on zinc(II) complexes with Schiff-base ligands and dicyanometallates: synthesis,crystal structures,and luminescent properties

Four new d¹⁰ heterometallic coordination polymers have been obtained using three Schiff-base ligands, zinc(II) nitrate, and dicyanometallates: ₁^∞[{Zn₃(Salen)₂}{μ-Au(CN)₂}₂] (1); ₁^∞[Zn(Saldmen){μ-Ag(CN)₂}]·2H₂O (2); ₁^∞[Zn(Salampy){μ-Ag(CN)₂}] (3); ₁^∞[Zn(Salampy){μ-Au(CN)₂}] (4). The Schiff bases are obtained from condensation of salicylaldehyde with ethylenediamine (H₂Salen); N,N-dimethyl-ethylenediamine (HSaldmen) and, respectively, 2-aminomethyl-pyridine (HSalampy). The dicyanometallates are K[Ag(CN)₂] and K[Au(CN)₂]. The compounds were characterized by X-ray single-crystal diffraction, infrared spectroscopy, UV–vis spectroscopy, and elemental analysis. In compound 1, the homotrimetallic units, {Zn₃(salen)₂}²⁺, are connected by two [Au(CN)₂]^? bridges, forming a 1-D double chain. In compounds 2–4, the crystal structures show polymeric zigzag chains generated by the mononuclear zinc(II) nodes and [M(CN)₂]^? spacers. The luminescence properties of the new heterometallic polymers have also been investigated.     

Supramolecular self-assembly of two Cu(II) complexes with 1,2,4-triazole derivatives: syntheses,crystal structures and magnetic properties

Two two-dimensional coordination complexes, {[Cu₄(BTM)₆(OPA)₄] · 4DMF · 3H₂O} _n (1) and {[Cu(BDTM)(OH)](ClO₄) · 2H₂O} _n (2) (BTM = bis(1,2,4-triazol-1-yl)methane, BDTM = bis(3,5-dimethyl-1,2,4-triazol-1-yl)methane, OPA²⁻ = ortho-phthalic dianion, DMF = N,N-dimethylformamide), were synthesized and structurally characterized. Each Cu(II) ion locates in a distorted square pyramidal geometry in 1, in which OPA²⁻ ligands bridge Cu²⁺ ions along a axis to form a magnetic transmission chain and BTM ligands act as flexible spacers to construct the two-dimensional layer structure. In 2, each Cu²⁺ ion adopts tetra-coordination geometry to two hydroxyl groups and two triazolyl nitrogen atoms from two different BDTM ligands. Two hydroxyl groups bridge two Cu²⁺ ions to form a rhombic diamond, and four BDTM ligands connect four diamonds to form a 36-membered macrocyclic structure with large channels along a axis. Magnetic properties revealed that both OPA²⁻ and OH⁻ mediate anti-ferromagnetic interactions between Cu²⁺ ions with J = − 0.06(3) and −301.9(2) cm⁻¹ for 1 and 2, respectively. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Cyanide-bridged polynuclear heterobimetallic complexes: synthesis,crystal structures,and magnetic properties

Transition Metal Chemistry - The reactions of [MnIII(3-EtOSalen)(H2O)2]ClO4 (Salen=N,N-ethylenebis(salicylideneaminato)dianion) with K3[M(CN)8] (M=Mo, W) have been investigated, from which...     

Tetranuclear CoII, MnII, and CuII complexes of a novel binucleating pyrazolate ligand preorganized for the self-assembly of compact [2 x 2]-grid structures

A straightforward synthesis toward the preparation of the rigid pyrazolate ligand L(H) featuring bipyridyl side-arms is described, starting from 2,2'-bipyridyl-N-oxide as the sole organic building block. In this context, optimized procedures for the synthesis of the organic intermediates 6-acetyl-2,2'-bipyridine 1 and 6-methylcarboxy-2,2'-bipyridine 2 are reported. The new ligand comprises two proximate terpyridine-like binding sites and is shown to form discrete [2 x 2]-grid complexes with CoII, MnII, and CuII in a highly selective self-assembly process, even in the presence of excess metal precursor. The thus obtained complexes [Co4L4][Na(NO3)4](NO3) (3), [Mn4L4](PF6)4 (4), and [Cu4L4](ClO4)4 (5) are fully characterized, including X-ray crystallographic analyses, and their magnetic properties are discussed. All three complexes show weak to moderate antiferromagnetic coupling between the four nuclei. The stability of the grid structures proved very high, as dissociation or exchange between metal ions in solution was not observed in a set of competition experiments.     

Syntheses,structures and magnetic studies of three heterometallic Fe2Ln 1D coordination polymers

Three new heterometallic 1D coordination polymers [Fe^III₂Pr(4-Me-sal)₄(2,2′-bipy)₂(H₂O)₆](NO₃) · 2MeOH · 1.5H₂O (1), [Fe^III₂Gd(4-Me-sal)₄(2,2′-bipy)₂(H₂O)₅]Cl_1/2(NO₃)_1/2 · 5H₂O (2) and [Fe^III₂Dy(4-Me-sal)₄(2,2′-bipy)₂(H₂O)₅]Cl_1/2(NO₃)_1/2 · 5H₂O (3) have been synthesized. 1 and 2 were characterized by single-crystal X-ray crystallography, and 3 was shown to be isomorphous to 2 by X-ray powder diffraction. Magnetic studies show that the three compounds show a similar temperature dependence of their magnetic susceptibilities over the range 1.8–300 K. The observed decrease of χT with decreasing temperature for all three compounds could be the result of antiferromagnetic interactions between Fe–Ln centres and/or the depopulation of the Stark sublevels in the case of the anisotropic Ln ions (Pr^III and Dy^III).