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In this paper, two-dimensional numerical simulations were conducted to study the correlation relationship between detonation cell size and ignition delay time of self-sustained stoichiometric H2/air detonation. The results first show that the average ignition delay time in the induction zone equals to the average period of triple-wave point movement. The shock dynamics and chemical reaction kinetics couples together in self-sustained detonation.

Traditional hypersonic wind tunnels usually produce test flows with low total temperatures and at low sound speeds, and therefore, the thermochemical reaction, one of the key mechanisms in hypersonic flows, is ignored in its experiments. As a result, the real gas effect on the aerodynamic force and moment measurement becomes a very difficult problem to solve in the hypersonic ground tests, and once it was identified as an unknown “unknown” [1]. During the high Mach number and high-altitude segment of the first entry flight of the Space Shuttle orbiter, the vehicle exhibited a nose-up pitching moment increment relative to preflight prediction. Woods et al. [2] noted that preflight predictions based on the aerodynamics in the aerodynamic design data book indicated that a 7.5° deflection of the body flap would be required to trim the Space Shuttle orbiter for the center of gravity and vehicle configuration. In reality, the body flap had to deflect too much large values (δ ≈ 16°) to maintain trim at the proper angle of attack (α = 40°). The deflection of 16° was close to the possible deflection limitation, and the more deflection would lead to a serious flight test accident. Comparison of equilibrium-air computations with perfect gas mode indicates that at least the main part of the so-called hypersonic anomaly was due to real gas effects at very high Mach numbers [3].

A new kind of hollow titania spheres-chitosan (hTiO2-CS) hybrid membranes was prepared by a physical blending method. hTiO2 spheres were found to disperse well in the as-prepared hTiO2-CS hybrid membranes. Their incorporation can reduce the chitosan crystallinity and enhance slightly its hydrophilicity and thermal stability. Subsequently, hTiO2-CS/PAN composite membranes comprising of the hTiO2-CS hybrid membrane as separation layer and a polyacrylonitrile (PAN) membrane as support layer were fabricated. Compared to the CS/PAN membrane, all of them exhibit a much better flux and separation factor for a 90 wt % aqueous solution of isopropanol at 80 °C. This promising kind of composite membranes may find potential application in the dehydration of alcohols.

Algebraic soft-decision decoding (ASD) of Reed–Solomon (RS) codes can obtain significant coding gain over the hard-decision decoding with polynomial complexity. Compared with other ASD algorithms, the low-complexity chase (LCC) decoding testing 2η test vectors has less computation complexity with similar or better coding gain. To reduce the latency of the interpolation, one major step of the LCC decoding, multiple interpolators can be applied and the pipelined architecture is usually adopted to make the throughput of the decoder higher. However, for application specific integrated circuit (ASIC) implementation and practical applications, the area and power consumption of the pipelined decoder are not preferable. This study proposes a modified serial LCC decoder architecture which reduces the power consumption and hardware requirement while keeping the shortest critical path as one adder, one multiplexer and one multiplier. As major contributions of this study, a novel re-encoder and erasure decoder block and an improved way to compute syndromes are proposed to reduce the whole latency of the decoder. For a (458, 410) RS code over Galois Field (GF)(210) with η=8, the hardware requirement and power consumption of the proposed LCC decoder are reduced by 23 and 25% than those of the common pipelined counterparts, respectively.

Enzyme@capsule nano/microsystems, which refer to the enzyme-immobilized capsules, have received tremendous interest owing to the combination of the high catalytic activities of encapsulated enzymes and the hierarchical structure of the capsule. The preparation of capsules and simultaneous encapsulation of enzymes is recognized as the core process for the rational design and construction of enzyme@capsule nano/microsystems. The strategy used has three major steps: (a) generation of the templates, (b) surface coating on the templates, and (c) removal of the templates, and it has been proven to be effective and versatile for the construction of enzyme@capsule nano/microsystems. Several conventional methods, including layer-by-layer assembly of polyelectrolytes, liquid crystalline templating method, etc., were used to design and construct enzyme@capsule nano/microsystems, but these have two major drawbacks. One is the low mechanical stability of the systems and the second is the harsh conditions used in the construction process. Learning from nature, several biomimetic/bioinspired methods such as biomineralization, biomimetic/bioinspired adhesion, and their combination have been exploited for the construction of enzyme@capsule nano/microsystems. In this chapter, we will present a general protocol for the construction of enzyme@capsule nano/microsystems using the latter approach. Some suggestions for improved design, construction, and characterization will also be presented with detailed procedures for specific examples.

Co-doped 3C-SiC nanowires were synthesized using high-purity SiO, Co and carbon nanotubes as starting materials. The nanowires consist of cubic SiC with diameters ranging from 20 to 200 nm and lengths up to tens of micrometers, High resolution transmission electron microscopy reveals that the nanowires preferentially grew along the [111] direction. Extended X-ray absorption fine structure (EXAFS) reveals that the secondary phase of Co3O4 was formed in the Co-doped 3C-SiC sample. The nanowires exhibit the coexistence of paramagnetic response and weak ferromagnetic behavior. The influence of secondary phase Co3O4 on the magnetic properties in the Co-doped SiC nanowires has been briefly discussed. (C) 2014 Elsevier B.V. All rights reserved.

Six compounds of the general formula [Ln(pfpr)3]2(NITPhOMe)·nH2O, where LnNd, Gd, Dy, Ho, Er, Y, pfpr=pentafluoropropionate, NITPhOMe=2-(4'-methoxyphenyl)-4,4,5, 5-tetra-methylimidazoline-1-oxyl-3-oxide, and n=4 (for Nd, Dy, Er); 3 (for Gd); 6 (for Ho); 5 (for Y), have been synthesized. These complexes were characterized by elemental analyses, IR, electronic spectra and molar conductances. The variable temperature (4–300 K) magnetic susceptibility of the complex [Gd(pfpr)3]2(NITPhOMe)·3H2O was determined. The observed susceptibility data were fit to those from theoretical magnetic equation by least-squares method. The exchange integral, J, was found to be equal to 2.14 cm−1. This indicates a weak ferromagnetic spin-exchange interaction between the radical and the gadolinium(III) ion.

Six novel μ-oxamido binuclear complexes, namely Cu(axpn)Ln(L)2(ClO4)3 (Ln: Eu, Gd, Tb, Nd, Ho, Er), where oxpn is N,N'-bis(3-aminopropyl) oxamido, L denotes 5-nitro,10-phenanthroline (abbreviated as NO2-phen), have been synthesized and characterised. The magnetic susceptibility of complexes Cu(oxpn)Gd(NO2-phen)2(ClO4)3.2H2O was measured over the 4–300 K and the observed data were successfully simulated by equation based on spin Hamiltonian operator (H = -2J1 · S2), giving the exchange integral J(Cu-Gd)=-1.62 cm−1. This indicates a weak antiferromagnetic interaction between the Cu(II) and Gd(III) ions.

Six novel μ-oxamido heterobinuclear complexes, namely Cu(oxae)Ln(Me2bpy)2-(ClO4)3 (LnLa, Nd, Gd, Tb, Ho, Er), where oxae denotes N, N'-bis(2-aminoethyl)oxamido dianion, Me2bpy is 4,4'-dimethyl-2,2'-bipyridyl, have been synthesized and characterised by elemental analyses, IR, conductivity measurements and electronic spectra. The temperature dependence of the magnetic susceptibility of Cu(oxae)Gd(Me2bpy)2(ClO4)3 has been measured over the range 4–300 K. The least-squares fit of the experimental susceptibilities yielded J = 1.87 cm−1. The observed Gd(III)-Cu(II) coupling is ferromagnetic. One plausible mechanism that can cause a ferromagnetic coupling between Gd(III) and Cu(II) is discussed in terms of spin-polarization.

A unique coordination polymer, {[CuLNa(ClO4)]·H2O}n (1), was isolated from the solution containing sodium perchlorate and the neutral macrocyclic oxamidocopper(II) complex [CuL] (H2L = 2,3-dioxo-5,6:13, 14-dibenzo-7, 12-bis(ethoxycarbonyl)-1, 4, 8, 11-tetraazacyclotetradeca-7, 11-diene). The complex is composed of [Na2Cu2] tetrametallacycles bridged by perchlorate ions to form infinite one-dimensional chains which are stacked via τ-τ interactions and weak coordination bonds to result in a two-dimensional supramolecular network. The perclorate ions were found to coordinate to sodium atoms in the unusual bridging chelating tridentate mode of μ2-(O:O′,O″).

A dinuclear manganese(III) tetradentate Schiff-base complex, [Mn2(salophen)2(4,4′-bipy)3](BPh4)2 (1) (salophen = N,N′-o-phenylene-bis(salicylideneaminato)), has been synthesized and structurally characterized. Compound 1 crystallized in the triclinic, P 1 space group, a = 13.431(4), b = 13.791(4), c = 13.886(4) A, α = 73.599(5)°, β = 80.410(6)°, γ = 71.241(5)°, V = 2328.3(12) A3. Complex 1 contains two Mn(salophen) moieties bridged by 4,4′-bipy to form a dinuclear unit, with two terminal 4,4′-bipy ligands. Variable temperature magnetic susceptibility (2–300 K) shows very weak ferromagnetic interactions between the Mn(III) ions.

Two one-dimensional (1-D) chain manganese-nitroxide complexes {[Mn(NIT4Py)2(ip)(H2O)2]·4H2O}n (1) and [Mn(IM4Py)2(ip)(H2O)2]n (2) (NIT4Py = 2-(4′-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, IM4Py = 2-(4′-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and ip = isophthalate anion) have been synthesized and characterized by elemental analyses, IR spectrum and electronic absorption spectra. Complex 1 was structurally characterized and it crystallizes in neutral 1-D chains where MnII nitroxide units [Mn(NIT4Py)2(H2O)2] are linked by isophthalate anions. The magnetic measurements show that complex 1 exhibits antiferromagnetic couplings, while complex 2 exhibits ferromagnetic interactions between the MnII ion and the nitroxide radicals.

Two novel lanthanide picolinate complexes [Ln(pic)3](Ln = Nd(1) and Sm(2); Hpic = picolinic acid) were prepared by hydrothermal method. The results of an X-ray crystallographic analysis reveal that both of complexes are unique tris-carboxylato-bridged one-dimensional chain structures. This 1D chain consists of one zigzag strand and two helical strands formed by oxygen atoms of the carboxylato groups and metal ions. The luminescence properties of complex 2 show the characteristic transition of the Sm(III). The magnetic properties of complexes 1 and 2 also have been studied.

Two new binuclear cobalt(II) complexes, [Co2L1(μ2-DPP)]2+ (1) (HL1 = N, N, N′, N′- tetrakis (2-benzimidazolylmethyl)-2-hydroxyl -1,3-diaminopropane; DPP = diphenylphosphinate) and [Co2L2(μ2-BNPP)2]+ (2) (HL2 = 2,6-bis-[N,N-di(2- pyridylmethyl)aminomethyl]-4-methylphenol, BNPP = bis(4-nitrophenyl)phosphate) have been synthesized and their crystal structures and magnetic properties are shown. In 1, each CoII atom has a distorted trigonal bipyramidal coordination sphere with a N3O2 donor set and the central two CoII atoms are bridged by one alkoxo-O atom and one μ2-DPP ion with the Co1-Co2 separation of 3.542A. In 2, each CoII atom has a pseudo octahedral environment with a N3O3 donor set and the central two CoII atoms are bridged by a phenolic oxygen atom of L2 and two μ2-BNPP ions with the Co1-Co2 separation of 3.667A. Susceptibility data of 1 and 2 indicate intramolecular antiferromagnetic coupling of the high-spin CoII atoms.

Two novel complexes [Zn(NIT3-py)(tp)]n 1 and [Zn(im3-py)(tp)]n 2 (NIT3-py = 2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, im3-py = 2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl, tp = terephthalato) have been synthesized and structurally determined by X-ray diffraction analysis. Complex 1 is, monoclinic, space group P2/c, with a = 12.6459(14), b = 6.9110(8), c = 20.0376(17) A, β = 112.030(5), V = 1623.3(3) A3 with Z = 2, for d calc = 1.428 Mg/m3. The analog 2 is, monoclinic, space group P2/n, with a = 12.2313(15), b = 6.8478(9), c = 19.908(3) A, β = 107.368(2), V = 1591.4(3) A3, with Z = 2 for d calc = 1.390 Mg/m3. X-ray analysis reveals that both Zn(II) ions are four-coordinated by two carboxylate oxygen atoms and two pyridyl-N atoms from nitroxide radicals to form a tetrahedron geometry. Each terephthalate dianion bridges two Zn(II) ions in bis-monodentate mode, resulting in a 1D chain structure. Two New Zinc(II) Nitroxide Radical Complexes bridged by terephthalate have been synthesized and structurally determined by X-ray diffraction analysis, the description of which is shown in the text.

A novel two-dimensional grid dimeric manganese(III) tetradentate Schiff-base complex, {[Mn4(salen)4(C4H4O4)](ClO4)2}n1, (salen = N,N′-ethylene-bis-salicylideneaminato, C4H4O4 = succinic acid), has been synthesized and structurally characterized. X-ray structure analysis reveals that in 1, succinic acid acts as a tetradentate ligand, each linking four [Mn2(salen)2]2+ moieties via carboxyl O atoms into a 2D unique net containing 30-membered cyclic centrosymmetrical polygonal grids.

A new double asymmetric μ1,1-azido bridged binuclear copper(II) complex, [Cu2(μ1,1-N3)2(Him2-py)2(N3)2] (Him2-py = 2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-hydroxy), has been synthesized and characterized structurally and magnetically. The crystal structure shows this complex is binuclear with copper(II) in a distorted square-pyramidal geometry, bridged by double asymmetric end-on azide ligands. The variable temperature magnetic susceptibility analyses reveal weak antiferromagnetic interaction mediated by the bridge.

A lanthanide complex [Nd(tcph)(Htcph)(H2O)5] (1) (H2tcph = tetrachlorophthalic acid) has been characterized by X-ray single crystal diffraction, elemental analysis, IR, UV-Vis and fluorescence spec...

Two new binuclear copper(II) complexes containing four spin carriers with pyridyl-substituted nitroxide radicals have been synthesized and characterized structurally and magnetically. These complexes are formulated as [Cu2(oxap)(IM4py)2](ClO4)2 (1) and [Cu2(oxap)(NIT4py)2](ClO4)2 (2), respectively, in which oxap stands for N,N′-bis(2-aminopropyl). IM4py stands for 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and NIT4py for 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. The structures of the complexes consist of centro-symmetric trans oxamido-bridged copper(II) binuclear units and nitroxide radicals. In 1 and 2 the copper atoms are in a distorted square plane and radicals (IM4py and NIT4py) coordinate to copper via nitrogen atoms from pyridine rings. Magnetic analysis indicates that 1 and 2 exhibit strong metal-metal antiferromagnetic coupling through oxamido-bridged and antiferromagnetic exchange interactions between copper(II) ion and radicals, respectively. The magnetic behaviors ...

Two hetero-spin metal–radical complexes [Cu(NIT2Py)2Cl] · ClO4 · H2O ( 1 ) and [Co(NIT2Py)2(H2O)(CH3OH)] · (ClO4)2 ( 2 ) (NIT2Py = 2-(2′-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were synthesized and characterized structurally and magnetically. The two complexes crystallize in mononuclear structures where two radical ligands coordinate to the metal ion through the nitroxide oxygen atoms directly via the bidentate chelating mode. The magnetic measurements show that two complexes exhibit strong antiferromagnetic interactions between the metal ions and the nitroxide radicals.

The synthesis, structural characterization, and magnetic behavior of a novel one-dimensional azido-bridged manganese(III) complex of formula [Mn(L){sub 2}N{sub 3}] (1) is reported, where HL is the bidentate Schiff base obtained from the condensation of salicylaldehyde with 4-methoxy aniline. Complex 1 crystallizes in the monoclinic system, space group P2{sub 1}/n, with a=11.743(4) A, b=24.986(9) A, c=13.081(5) A, {beta}=95.387(7){sup o} and Z=2. The complex is of one-dimensional chain structure with single end-to-end azido bridges and the manganese(III) ion has an elongated octahedral geometry. Magnetic studies show that the weak antiferromagnetic interaction is mediated by the single end-to-end azido bridge with the exchange parameter J=-5.84 cm{sup -1}. - Graphical abstract: A novel azido-bridged manganese(III) complex with bidentate Schiff base ligands has been prepared and characterized structurally and magnetically. The complex is of one-dimensional chain structure with single end-to-end azido bridges in axial positions. Two bidentate Schiff base ligands coordinate in the equatorial mode. The magnetic measurements show that the complex exhibits weak antiferromagnetic interaction.

A novel iron (II) complex of formula [Fe3(2,2′-bipy)6(ox)3]·12.25H2O (2,2′-bipy = 2,2′-bipyridine, ox = oxalate) has been prepared and structurally characterized by X-ray crystallography. In the complex, the metal atoms are six-coordinated in distorted octahedral environment. In the complex [Fe(ox)3]4− anions and water molecules are linked together into 1D chain structure by hydrogen interaction. The red crystal of the complex is monoclinic, space group P21/c, with a = 22.932(6) A, b = 13.715(4) A, c = 22.493(6) A, β = 93.177(5)°, and V = 7063(3) A3 with Z = 4.

A novel one-dimensional complex salt with the formula [Cd(IM2py)2][Au(CN)2]2 (IM2py = 2-(2′-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl), has been synthesized and its structure was determined by single-crystal X-ray diffraction methods. The coordination geometry around Cd(II) ion is a distorted octahedral. IM2py coordinates to Cd(II) via pyridyl- and imino-N atoms to form a planar, five-membered chelate ring. [Cd(IM2py)2][Au(CN)2]2 units are linked through weak Au ··· Au interactions, generating an infinite 1D zigzag chain. Magnetic studies show weak antiferromagnetic coupling between two radicals through the diamagnetic Cd(II) ion.

Two Mn(II)–Au(I) supramolecular assemblies {{Mn[Au(CN)2]2(H2O)4} [Au(CN)2]2(H2bpy) · H2O}(bpy = 4,4′-bipyridine) 1 and {Mn(4,4′-dmbpy) [Au(CN)2]2(CH3OH)} (4,4′-dmbpy = 4,4′-dimethyl-bipyridine) 2 have been synthesized and magnetic properties have been investigated The interplay of aurophilicity, coordination, hydrogen-bonding and π–π interactions in two complexes result in three-dimensional network.

The novel oxamidato-bridged dinuclear [(CuL)VO(H2O)(C2O4)] complex incorporating a macrocyclic oxamide has been synthesized, spectroscopically, structurally, and magnetically characterized, where (CuL = [5,6: 14,15-dibenzo-1,4,8,12- tetraazacyclopentadeca-7,13-diene-2,3-dione(2-)]copper(II)). Magnetic measurements indicate ferromagnetic interaction between Cu(II) and VO(IV) ions within the complex.

A new binuclear copper(II) complex [Cu2(oxpn)(IM2py)2](ClO4)2, containing four spin carriers with pyridyl-substituted nitroxide radicals has been synthesized and characterized structurally and magnetically (oxpn = N,N′-bis(3-aminopropyl)oxamido, IM2py = 2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl). The structure of the complex consists of centrosymmetric trans oxamido-bridged copper(II) binuclear units and nitroxide radicals. The coordination geometry around each copper atom is distorted square pyramidal and the apical position is occupied by a nitrogen atom of the imidazoline ring of a radical ligand. Magnetic analysis indicates that the complex exhibits strong antiferromagnetic coupling between copper(II) ions through the oxamido bridge and a ferromagnetic interaction between copper(II) ions and radical ligands. The magnetic behaviour is discussed with reference to the crystal structure.

A novel one-dimensional azido-bridged coordination polymer of formula [CU2(L)(2)(H2O)(N-3)(4)](n) (1) has been synthesized and charac-terized crystallographically and magnetically, where L is 5-methylpyrimidin-2-amine. Complex 1 consists of 1D chain in which the Cu(II) ions with a square pyramidal geometry are alternately bridged by asymmetric single and symmetric double end-on (EO) azido ligands. Magnetic analysis reveals that the dominating ferromagnetic interaction is mediated by the symmetric double azido bridge with the exchange parameter J=55.17cm(-1). (c) 2007 Elsevier B.V. All rights reserved.

A transition metal-radical heterospin complex [Ni(salox) 2 (IM4Py) 2 ] ( 1 ) (salox = salicylaldoxime, IM4Py = 2-(4′-pyridinyl)-4,4,5,5-tetramethylimidazoline-l-oxyl) ( 1 ) has been synthesized based on the substitution reaction of Ni(salox) 2 (py) 2 and IM4Py. Compound 1 exhibits a chain structure created by the intermolecular hydrogen bonds. Magnetic measurements show intermolecular antiferromagnetic interactions in 1 .

The influence of interface growth interruption on electron spin relaxation time tau s in GaAs/AlGaAs (1 1 0) quantum wells (QWs) grown by solid source molecular-beam epitaxy (SSMBE) has been investigated by grazing incidence X-ray reflectivity and time-resolved Kerr rotation spectroscopy (TRKR). Various inverted interface interruption times were used in growing QWs. Interface roughness of these QW samples was studied by grazing incidence X-ray reflectivity. The simulated results of reflectivity, curves by standard software indicated that interface roughness decreased as the interface growth interruption time increased. TRKR measurements at room temperature showed that the appropriate growth interruption could increase spin relaxation time in GaAs/AlGaAs QWs drastically. This dramatic increase was explained by the suppression of the D'yakonov-Perel' interaction. (c) 2006 Elsevier B.V. All rights reserved.

A novel tetranuclear cubane-like complex [Ni4(hbzim)4(N3)4(mal)2(CH3OH)(H2O)] (Hhbzim = 2-hydroxymethylbenzimidazole, mal = 4-methoxyaniline) has been synthesized and characterized structurally as well as magnetically. The structure analyses reveal that this complex consists of a Ni4O4 cubane core and the different coordinate environments of the nickel(II) ions result in a cubane structure with differing Ni–Ni distances and Ni–O–Ni angles. The magnetic properties of this complex have been interpreted by employing one-J and two-J model. The results show that ferromagnetic interaction dominates in the complex.

A new tetranuclear complex [Fe4L2(μ-O)2(μ->OH)2](ClO4)4·H2O (1), (HL = N,N,N′,N′-tetrakis-[(2-pyridyl)methyl]-2-hydroxypropane-1,3-diamine) has been synthesized and its crystal structure and magnetic properties are shown. X-ray crystallography reveals that complex 1 contains a quadruply-charged, tetranuclear iron(III) cation and four perchlorate anions. In 1, the Fe4O6 core is composed of a tetrahedron of iron atoms bridged by six oxygen atoms (two oxo, two hydroxo, and two alkoxo groups from L). This results in an adamantane-type geometry with the iron atoms occupying the bridgehead positions. Susceptibility data of 1 indicate strong intramolecular antiferromagnetic coupling of high-spin FeIII atoms.

A novel complex Zn(NIT2-py)3(ClO4)2(NIT2-py = 2-(2′-pyridyl)-4,4,5,5-tetramethyl-2-imidazoline-1-oxyl-3-oxide) (1) has been synthesized and characterized structurally and magnetically. The metal coordination sphere is fully occupied by three chelating nitroxide ligands, showing a distorted octahedral geometry. Temperature dependence of susceptibility measurements shows a weak ferromagnetic coupling between NIT2-py radicals with J = 2.13 cm−1. The field dependence of the magnetization further confirms that the ground state of the compound S = 3/2 results from ferromagnetic interactions within the complex 1.

A Prussian-blue analogue Mn 3 [Cr(CN) 6 ] 2 ·12H 2 O has been prepared and characterized by single crystal X-ray analysis and magnetic measurements. The complex has a disordered face-centered cubic lattice and shows two magnetic transition temperatures of 74 and 61 K.

Three new metal–radical complexes of the formula [M(NITm-Py)2(N3)2(DMSO)2] [M = Cu(II) 1, Ni(II) 2, Co(II) 3; NITmPy = 2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide] were synthesized and characterized structurally as well as magnetically. Three complexes are three-spin complexes in which two NITmPy radical ligands are coordinated to the metal ion through the nitrogen atoms of the pyridyl rings. The magnetic behaviors of the three complexes are investigated. Complexes 1 and 2 show ferromagnetic interactions while antiferromagnetic coupling is predominant for complex 3. The magnetic properties are analyzed in connection with their structures and the magnetic exchange mechanism is discussed.

Four heteronuclear complexes Mn(CuL)2(SCN)2 (1), {[Mn(CuL)2(mu-dca)2].2H2O}n (2), Zn(CuL)2(SCN)2 (3), and [Fe(CuL)(N3)2]2 (4) incorporating macrocyclic oxamide ligands have been synthesized and structurally characterized. L is the dianion of diethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo[1,4,8,11]-tetraazacyclotetradecine-13,18-dicarboxylate, and dca is the dicyanamide. The structure of 1 or 3 consists of oxamido-bridged trinuclear [MIICuII2] molecules (for 1, M is the manganese(II) ion, and for 3, M is the zinc(II) ion). Both of them consist of 1D supramolecuar chains via pi-pi interactions. The structure of 2 also has the oxamido-bridged trinuclear [MnIICuII2] structure units and consists of 2D layers formed by the linkage of copper(II) and manganese(II) atoms via the oxamido and mu1, 5-dca bridges. Complex 4 consists of oxamido-bridged tetranuclear [FeII2CuII2] molecules and arranges in 1D chains. Different co-ligands may result in different structures in this macrocyclic oxamide system. The variable-temperature magnetic susceptibility measurements (2-300 K) of 1 and 2 both show the pronounced antiferromagnetic interactions between the copper(II) and manganese(II) ions.

A novel malonate-bridged copper (II) compound of formula {[Cu4(4,4′-bpy)8(mal)2(H2O)4](ClO4)2(H2O)4(CH3OH)2}n (4,4′-bpy = 4,4′-bipyridine; mal = malonate dianion) has been prepared and structurally characterized by X-ray crystallography. This compound exhibits a novel three-dimensional network being composed of Cu-4,4′-bipyridine layers which are pillared by malonate bridge ligands. The copper(II) ions has two different coordination environment.