A Novel Binuclear Cu(Ⅱ) Complex with Nitroxide Radicals Exhibiting Ferromagnetic Interactions

A new binuclear Cu（Ⅱ） complex with nitronyl nitroxide radicals [Cu（NIT3Py）2Cl2]2（NIT3Py = 2-（3＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in monoclinic,space group C2/c with a = 38.483（4）,b = 7.2450（8）,c = 27.559（3） ,β = 134.0180（10）°,V = 5525.6（10） 3,C48H64Cl4Cu2N12O8,Mr = 1206.00,Z = 4,Dc = 1.450 g/cm3,μ（MoKα） = 1.025 mm-1,F（000） = 2504,S = 1.066,the final R = 0.0471 and wR = 0.1121 for 3286 observed reflections（I 2σ（I））.The title complex consists of centrosymmetric dinuclear units [Cu（NIT3Py）2Cl2]2,in which the copper ions are square-pyramidally coordinated by two pyridyl nitrogen atoms of two radical ligands and three chlorine anions,two of which bridge the copper ions.The magnetic measurements show ferromagnetic interactions between the copper ions and the radical ligands.

Two Tri-spin Complexes Based on Lanthanide (Ln~Ⅲ =Dy~Ⅲ and Tb~Ⅲ ) and Nitronyl Nitroxide Radicals: Syntheses, Structures and Properties

Two new tri-spin radical-Ln（III）-radical complexes, [Ln（hfac）3（NITPh-Ph）2] （Ln = Dy （1） and Tb （2）, NITPh-Ph = 4＇-biphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, and hfac = hexafluoroacetylacetonate） have been synthesized and characterized by X-ray diffraction analysis, elemental analysis, IR, Uv-visible and magnetic properties. X-ray analysis reveals that the two complexes are isomorphous and crystallize in the triclinic system, space group P1. For complex 1, a = 12.402（3）, b = 15.414（3）, c = 17.383（3） A, a = 68.61（3）, β = 81.97（3）, y = 79.40（3）°, V = 3031.7（11） A3, Z = 2, Mr = 1401.86, Dc = 1.536 g/cm^3, kt = 1.344 mm^-1, F（000） = 1398, the final GOF = 1.173, R = 0.0670 and wR = 0.1376 for 9035 observed reflections with 1 〉 2a（/）; while for complex 2, a = 12.397（3）, b = 15.391（3）, c = 17.395（4） A, a = 68.62（3）, fl = 81.97（3）, ）, = 79.60（3）°, V = 3030.0（11） A3, Z = 2, Mr = 1398.29, Dc = 1.537 g/cm^3,μ = 1.344 mm-1, F（000） = 1398, the final GOF = 1.130, R = 0.0644 and wR = 0.1382 for 8989 observed reflections with 1 〉 2a（/）. They all consist of the discrete adducts, in which the central Ln（lll） ions are coordinated by six oxygen atoms from three hfacs and two oxygen atoms from nitronyl radicals. The temperature dependency of magnetic susceptibilities for these two complexes is studied, showing that the magnetic interactions are governed by the depopulation of the Ln Stark levels.

Synthesis, Crystal Structure and Magnetic Properties of a New Zn(II)-Nitronyl Nitroxide Complex

A new complex [Zn（NIT-1′-MeBzlm）Cl2（H2O）] （NIT-1′-MeBzlm = 2-{2′-[（1′- methyl）benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been prepared and structurally characterized by X-ray diffraction method. Crystal data： monoclinic, space group P21/n, Z = 4, C15H21Cl2N4O3Zn, Mr = 441.63, a = 7.2225（10）, b = 30.849（4）, c = 8.8758（13）A, β = 103.904（2）°, V = 1919.6（5）A^3, Dc = 1.528 g/cm^3, μ（MoKα） = 1.579 mm^-1, F（000） = 908, R = 0.0436 and wR = 0.1029 for 2456 observed reflections with I〉 2σ（I）. X-ray analysis reveals that the Zn（Ⅱ） ion is four-coordinated with a distorted tetrahedron. There also exist H-bonds, π-π piling interactions and weak intermolecular contacts between the NO groups which form a mutual stagger 3-D network configuration. Magnetic investigation reveals that there exists intermolecular antiferro- and ferromagnetic interactions in the title complex.

A New One-dimensional Dicyanamide Bridged Zinc(II) Complex Containing Nitronyl Nitroxide Radicals:Synthesis,Crystal Structure and Magnetic Properties

A new one-dimensional dicyanamide bridged zinc（Ⅱ） complex containing nitronyl nitroxide radicals [Zn（NO3）（NIT-1′-MeBzIm）（dca）]n·（H2O）n （NIT-1′-MeBzIm = 2-{2′-[（1′-methyl）benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, dca = dicyanamide anion） has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in triclinic, space group P^-1, with a = 7.428（3）, b = 9.839（3）, c = 16.708（6） A^°, α = 93.270（4）, β = 101.642（4）,γ= 100.632（4）°, C17.5H21N8O5.5Zn, Mr = 496.79, V = 1169.7（7） A^°^3, Dc = 1.411 g/cm^3, μ（MoKα） - 1.096 mm^-1, Z = 2, F（000） = 512, R = 0.0583 and wR = 0.1663 for 4295 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that the zinc（Ⅱ） ion is six-coordinated with a distorted octahedral geometry. These units develop as 1D species where dicyanamide ligands bridge zine（ID ions. In addition, molecules are linked by π-π piling interactions to form 1-D double-chains. Magnetic investigation indicates that the weak intramolecular interactions are antiferromagnetic with J = -0.27 cm^-1, where the spin Hamitonian is defined as H = -2∑ijJijSiS within the complex.

Synthesis, Crystal Structure and Magnetic Properties of a Novel Azide-bridged Copper(Ⅱ) Coordination Polymers Containing Nitroxy Nitroxide

A novel azide-bridged copper（Ⅱ） coordination polymer, [Cu3（NITpPy）4（N3）6]n （NITpPy = 4-pyridyl-4,4,5,5-tetramethylimidazline-3-oxide-1-oxyl）, was structurally and magnetically characterized. It crystallizes in the triclinic space group P with a = 7.6932（10）, b = 14.5556（19）, c = 16.122（2） , α = 108.443（2）, β = 95.251（2）, γ = 104.236（2）°, V = 1631.7（4） 3, C48H64Cu3N30O8, Mr = 1379.87, Z = 1, Dc = 1.404 g/cm3, μ（MoKα） = 1.041 mm-1, F（000） = 713, the R = 0.0510 and wR = 0.1185 for 4285 observed reflections with I 2σ（I）. X-ray analysis reveals that the Cu（Ⅱ） ions are linked by nitrogen atom of μ1,1 azido ligands to form a Cu-Cu-Cu unit. The units are linked by μ1,3 azido ligands through a bridging style to form a one-dimensional coordination polymer. The variable-temperature magnetic susceptibility data of the complex show ferromagnetic interactions in the complex.

Synthesis,Crystal Structure and Magnetic Properties of an Oxalato-bridged Dinickel(Ⅱ) Complex with Nitronyl Nitroxide Radicals

A new oxalato-bridged dinickel（Ⅱ） complex [Ni2（NIT-MeImz）4（C2O4）]（Ac）2·8H2O has been synthesized and characterized structurally as well as magnetically.It crystallizes in monoclinic,space group C2/c with a=24.608（4）,b=21.399（3）,c=17.992（3）,β=131.680（2）°,V=7076（2）3,C50H86N16Ni2O24,Mr=1412.77,Z=4,Dc=1.326 g/cm3,μ（MoKα）=0.614 mm-1,F（000）=2984,R=0.0751 and wR=0.1791 for 2956 observed reflections with Ⅰ＆gt;2σ（Ⅰ）.X-ray analysis reveals that the crystal structure consists of [Ni2（NIT-MeImz）4（C2O4）]2＋ moiety and two Ac^- anions. Each nickel（H） ion is six-coordinated with a distorted octahedral geometry： two nitrogen atoms and two oxygen atoms from NIT-Melmz together with two other oxygen atoms from the oxalato ion. The 2-D net structure is formed and arranged through intermolecular H-bonding interactions. Magnetic measurements show antiferromagnetic interactions for this complex.

Synthesis, Crystal Structure and Magnetic Properties of a Cobalt(Ⅱ) Complex with Quinoxaline-substituted Nitronyl Nitroxide Radicals

A new complex with the formula [Co（acac）_2（NITQ）_2]×2CH_2Cl_2 1（acac = acetylacetone, NITQ = 2-（2′-quinoxalinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide）, was synthesized and elucidated structurally as well as magnetically in detail. The crystal belongs to the monoclinic system, space group P2_1/c with a = 9.6896（1）, b = 20.539（4）, c = 12.147（2） ？, β = 93.84（3）°, M_r = 997.65, V = 2412.1（8） ？~3, Z = 2, Dc = 1.374 g/cm, F（000） = 1038, m = 0.635 mm^（-1）, the final R = 0.0539 and w R = 0.1289 for 5998 observed reflections（I 〉 2σ（I））. The Co（Ⅱ） ion is coordinated by two nitrogen atoms of quinoxaline rings from two NITQs and four oxygen atoms from two acac ions to complete a distorted octahedral coordination environment. Compound 1 is further linked into a three-dimensional（3D） supramolecular network by hydrogen-bonding, Cl×××O weak contact and π···π stacking interactions. The magnetic measurements show compound 1 exhibits weak ferromagnetic interactions.

Nitroxide radical cathode material with multiple electron reactions

Organic materials with redox-active centers are regarded as promising candidates for rechargeable batteries in recent years for their light weight, low cost, environmental friendliness and structural diversity [1–4]. Organic materials, such as conducting polymers (polyacetylene, polypyrrole, polyaniline, etc.)[5], conjugated carbonyl compounds (quinone compounds, imides, etc.)[6–9] and nitroxide radical (N-O.)[10,11] compounds have been attempted as cathode materials in lithium-ion batteries (LIBs).

Crystal Structure and Magnetic Studies of a New Nitronyl Nitroxide Compound

Compound 1 was first synthesized and characterized. Its crystal structure and magnetic property were determined and investigated. Discussion about the molecule packing in crystal and the macroscopic magnetism was also presented, in combination with computing study of the spatial distribution over the molecule.

Synthesis of Poly(styrene-b-isoprene-b-styrene)viaNitroxide-mediated Radical Polymerization by a Novel Alkoxyamine

Bifunctional alkoxyamine bis-TIPNO derived from 2,2,5-trimethyl-4-phenyl-3-azahexane-3-oxyl （TIPNO） and α, ω-alkyl bromide by atom transfer radical addition（ATRA） was employed as “biradical initiator” for nitroxide-mediated radical polymerization（NMRP） of isoprene and styrene. The kinetics study for the polymerization of styrene at different time showed living features. The poly（styrene-b-isoprene-b-styrene） （SIS） copolymers have two glass transition temperatures, indicating the immiscibility of the corresponding blocks.

Bis-radicals (nitronyl nitroxide and imino nitroxide) Substituted Benzene with Long Alkyl Chain: Synthesis, Magnetic Study and Formation of LB film

The titled compound 1 as well as compounds 2 and 3 with similar chemical structures were prepared and characterized. The magnetic properties of 1 were investigated with SQUID (MPMS, quantum design) magnetometer. Studies with Langmuir-Blodgett (LB) technique indicated that stable condensed film of 1 could be formed at air-water interface and could be transferred onto various solid substrate under suitable conditions.

Novel Reaction of Nitroxide with Hantzsch Dihydropyridines

4-oxo-2, 2, 6, 6-tetramethylpiperidinyl-1-oxy radical (TEMPO), a nitroxide, oxidized 4-substituted Hantzsch 1,4-dihydropyridines (DHP) under UV irradiation in CH3CN to give aromatic products in good yields. A possible mechanism for the oxidation was suggested.

Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H_2O)_3]

A new Zn（Ⅱ） nitronyl nitroxide complex [Zn（NIT4Py）（PDA）（HzO）3] （NIT4Py = 2-（4＇-pyridyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2PDA = pyridine-2,5-dicarboxylic acid） has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P2 1/c with a = 16.881（8）, b = 7.356（4）, c = 18.857（9） A°,β = 108.616（6）°, V = 2219.1 （19）A°^3 ,C 19H25N4O9Zn, Mr = 518.80, Dc = 1.553 g/cm^3, μ（MoKa） = 1.165 mm^-1, F（000） = 1076, Z = 4, the final R = 0.0269 and wR = 0.0715 for 3193 observed reflections with I 〉 2σ（I）. The complex exists as discrete mononuclear molecules and the zinc（Ⅱ） ion is six-coordinated with one radical ligand （NIT4Py）, one bidentate pyridine-2,5-dicarboxylate anion and three water molecules. A three-dimensional network structure is formed through the intermolecular interactions.

1-Imino Nitroxide Pyrene, a Burst-type H^(+) Fluorescent Switch

1-Imino nitroxide pyrene 1 has been characterized as a H^＋ fluorescent switch. The effects of various interfering species, solvents and the irradiation of ultraviolet light on the fluorescence intensity of 1 are also investigated. 1 fluoresces weakly in the 85% ethanol media containing no more than 4.5x10-5 mol/L of H^＋ （HCI）, but can produce a burst increase of about 4 times in the fluorescence intensity when the concentration of H＋ is increased to or over 4.9×10^-5mol/L. The extremely sharp response of 1 to H＋ occurs only within such a narrow concentration range. Moreover, the decrease of H^＋ concentration through adding sodium hydroxide causes the fluorescence quenching, suggesting that 1 may serve as a fluorescent switch for monitoring the concentration change of H＋ around the point of 4.5×10^-5 mol/L.

ESR Approach to the Nature of Solvation by Using s-Butyl n-Heptafluorobutyryl Nitroxide Probe

Stable s-butyl n-heptafluorobutyryl nitroxide 3 has been generated in an electron transfer reaction in F113 ( CFCl2CF2Cl ) solution at r.t. The aN values for 3 in 11 aprotic solvents show a linear correlation with cybotactic solvent parameters ET and Z. The physical significance for slopes, slope×ET or slope×Z, and the extrapolated intercepts on the aN axis are well established. The plots of aN versus noncybotactic solvent parameters, such as dipolar moment and dielectric constant, are badly behaved.

Synthesis, Crystal Structure and Magnetic Properties of Cobalt(II) Complex Involving Imino Nitroxide Radicals

A novel compound [Co(IM2-Py)2(NO3)]?(NO3) (IM2-Py = 2-(2?-pyridyl)-4,4,5,5- tetramethylimidazoline-1-oxyl) has been prepared and structurally characterized by X-ray diffrac- tion method. It crystallizes in orthorhombic, space group P212121 with a = 11.031(2), b = 13.492(3), c = 20.467(4) ?, V = 3046.0(11) ?3, C24H32CoN8O8, Mr = 619.51, Z = 4, Dc = 1.351 g/cm3, μ(MoKα) = 0.620 mm?1, F(000) = 1292, R = 0.0506 and wR = 0.0845 for 3752 observed reflections with I > 2σ(I). X-ray analysis reveals that the crystal structure consists of [Co(IM2- Py)2(NO3)]+ moiety and a NO3 anion. The cobalt(II) ion is six-coordinated with a distorted octahedral geometry. Tempera- ? ture dependence of susceptibility measurements show that there exist an antiferromagnetic inter- action in the compound.

Synthesis of C_(60) Nitroxide Derivatives

C60 derivatives covalently linked with the nitroxide radical of 2, 2, 6,6- tetramethylpiperidine-l-oxyl have been synthesized by the following new method: C60 reactswith 4-oxo-2. 2, 6, 6-tetramethyl-piperidinyloxyl (4-oxo-TEMPO) and an amino acid.

Synthesis and Crystal Structure of a New One-dimensional Zn(II) Nitronyl Nitroxide Complex Bridged by Pyridine-2,4-dicarboxylate Anion

A new one-dimensional （1-D） Zn（Ⅱ） nitronyl nitroxide complex bridged by pyridine-2,4-dicarboxylate anion, [Zn（NIT4Py）（2,4-PDA）（H2O）2], （NIT4Py = 2-（4′-pyridyl）-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide and 2,4-PDA = pyridine-2,4-dicarboxylate anion）, has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.834（2）, b = 7.4376（10）, c = 18.295（3） A, β = 102.848（2）°, V = 2233.2（5） A^3, C19H23N4O3Zn, Mr = 500.78, Dc = 1.489 g/cm^3,μ（MoKa） = 1.152 mm^-1, F（000） = 1036, Z = 4, the final R = 0.0390 and wR = 0.0915 for 3234 observed reflections. In the complex, each zinc（Ⅱ） ion is six-coordinated by one nitrogen atom of the radical ligand （NIT4Py）, one nitrogen atom and two oxygen atoms of two 2,4-PDA anions and two oxygen atoms of two water molecules. Each 2,4-PDA anion bridges two Zn（Ⅱ） ions via a tridentate mode into a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.

Syntheses and Crystal Structures of Two New Zinc(Ⅱ) Nitroxide Radical Complexes Bridged by Isophthalate

Two novel complexes [Zn（NIT3-py）（ip）]n 1 and [Zn（im3-py）（ip）]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, ip = isophthalate） have been synthesized and structurally determined by X-ray diffraction. Crystal data for 1： C32H36N6O8Zn, Mr= 698.04, monoclinic, space group Cc with a = 23.600（3）, b = 10.2073（12）, c = 13.4027（16）A,β = 92.586（2）°, V = 3225.3（7） A^3, Dc= 1.438 g/cm^3, F（000） = 1456,μ（MoKa） = 0.822 mm^-1, Z = 4, the final R = 0.0390 and wR = 0.1032 for 6037 independent reflections with Rint = 0.0214. Crystal data for 2： C32H36N6O6Zn, Mr= 666.04, monoclinic, space group C2/c with a = 24.434（4）, b = 13.543（2）, c = 10.2379（16） A, β = 109.024（2）°, V = 3202.8（9）A3 Dc= 1.381 g/cm^3, F（000） = 1392,μ（MoKa） = 0.820 mm^-1, Z = 4, the final R = 0.0304 and wR = 0.0658 for 2833 independent reflections with Rint = 0.0307. X-ray analysis reveals that both Zn（ Ⅱ ） ions are four-coordinated by two pyridyl-N atoms from nitroxide radicals and two carboxylate oxygen atoms to form distorted tetrahedral geometries. Each isophthalate dianion binds two Zn（ Ⅱ ） ions in a monodentate mode, leading to a I-D chain structure.

Syntheses, Crystal Structures and Magnetic Properties of a New Nitronyl Nitroxide Radical and Its Cu(Ⅱ) Complex

A new compound （NIT-mNO2 = 4,4,5,5-tetramethylimidazoline-2-yl-（2＇-chlor-5＇- nitrophenyl）-3-oxide-l-oxyl） 1 and its complex （Cu（NIT-mNO2）（hfac）2） 2 have been synthesized and structurally and magnetically characterized. Complex 1 crystallizes in monoclinic, space group P211n with a = 10.6798（9）, b = 11.2705（9）, c = 12.9559（10）A, β = 107.3770（10）°, V = 1488.3（2） A^3, C13H15ClN3O4, Mr = 312.73, Z = 4, Dc = 1.396 g/cm^3, g（MoKa） = 0.276 mm^-1, F（000） = 652, the final R = 0.0606 and wR = 0.1773 for 3405 independent reflections with Rint = 0.0203. The nitronyl nitroxide unit （imidazoline ring） is not coplanar with the phenyl ring with the dihedral angle between them of 55.75°. The compound results in a 1-D zig-zag chain structure by intermolecular H-bond interaction. Compound 2 crystallizes in triclinic, space group Pi with a = 10.3699（10）, b = 10.6286（11）, c = 15.1683（15）A, a = 77.5330（10）, ,β = 773080（10）, y = 87.3420（10）＊, V = 1592.5（3） A^3, C23HITCIFI2N3O8Cu, Mr = 790.39, Z = 2, Dc = 1.648 g/cm^3, μ（MoKa） = 0.888 mm^-1, F（000） = 788, the final R = 0.0793 and wR = 0.2153 for 5794 independent reflections with Rint = 0.0196. The Cu（Ⅱ） ion is located at a center of symmetry, and each Cu（Ⅱ） is surrounded by six oxygen atoms at the vertices of a distorted tetragonal octahedron. Four of the six oxygen atoms belong to two hfac ligands and occupy the equatorial coordination sites, while the other two of NIT-mNO2 act as μ-1,5 bridge between the Cu（Ⅱ） ion, thus forming a 1-D chain structure. The magnetic susceptibility data indicate intermolecular antiferromagnetic interactions between compound 1 and intrachain ferromagnetic behaviors.