A blockwall‐type layered bis(dithiolato)nickelate radical salt exhibiting high‐ κ and two‐dimensional antiferromagnetic coupling feature

Author(s):  
Wan‐Wan Yao ◽  
Yin Qian ◽  
Xuan‐Rong Chen ◽  
Xiao‐Ming Ren
2013 ◽  
Vol 68 (8) ◽  
pp. 877-884 ◽  
Author(s):  
Wei Xu ◽  
Jian-Li Lin

Reaction of MnSO4 and trans-1,2-bis(4-pyridyl)ethene (bpe) results in a new coordination polymer, [Mn(H2O)2(bpe)(SO4)]·H2O. The title complex crystallizes in the polar monoclinic space group C2. The octahedrally coordinated Mn atoms are bridged by sulfate anions and bpe ligands to form two-dimensional sheets with (42·63·8) topology. This polar complex displays ferroelectricity with a remanent polarization (2Pr) of ca. 0:5779 μC cm-2, a coercive field (2Ec) of 8:8 kV cm-1, and a saturation of the spontaneous polarization (PS) of ca. 0:4177 μC cm-2. The magnetic behavior of the title complex suggests significant antiferromagnetic coupling interactions between Mn(II) ions bridged by sulfate anions. Furthermore, the title complex was subjected to elemental analysis, IR spectroscopic measurement and thermal analysis.


1988 ◽  
Vol 66 (8) ◽  
pp. 2079-2087 ◽  
Author(s):  
John S. Haynes ◽  
John R. Sams ◽  
Robert C. Thompson

Six new pyrazine-bridged complexes of iron(II) have been prepared and studied using magnetic susceptibility, differential scanning calorimetry, and vibrational, electronic, and Mössbauer spectroscopic methods. Fe(pyz)(CF3SO3)2 exhibits a susceptibility maximum at 4.4 K and analysis of the magnetic data according to a two-dimensional S = 2 system in the (isotropic) Heisenberg limit yields best-fit values of J = −0.26 cm−1 and g = 2.20. Variable temperature Mössbauer spectra between 4.2 and 1.6 K are also reported for this compound and show the onset of magnetic hyperfine splitting below ~3.8 K. Analysis of magnetic data for Fe(pyz)2(CH3SO3)2 and Fe(pyz)2(CF3SO3)2•CH3OH according to the two-dimensional Heisenberg model also indicates the presence of weak antiferromagnetic exchange in these complexes (J = −0.18 and −0.20 cm−1, respectively). No clear evidence for magnetic concentration was obtained from our studies on Fe(pyz)2(CIO4)2, Fe(pyz)(p-CH3C6H4SO3)2, and Fe(pyz)(p-CH3C6H4SO3)2•2CH3OH; any antiferromagnetic coupling in these complexes must be considerably weaker than in the other complexes studied.


2021 ◽  
Vol 7 (5) ◽  
pp. 73
Author(s):  
Hongdao Li ◽  
Jiao Lu ◽  
Jing Xie ◽  
Pei Jing ◽  
Licun Li

Two multi-dentate nitronyl nitroxide radicals, namely, bisNITPhPy ([5-(4-pyridyl)-1,3-bis(1′-oxyl-3′-oxido-4′,4′,5′,5′-tetramethyl-4,5-hydro-1H-imidazol-2-yl)]benzene) and NIT-3Py-5-4Py (2-{3-[5-(4-pyridyl)]pyridyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were assembled with CuII ions to obtain two-dimensional heterospin 2p–3d coordination polymers [Cu7(hfac)14(bisNITPhPy)2]n (1) and [Cu2(hfac)4(NIT-3Py-5-4Py)]n (2) (hfac: hexafluoroacetylacetonate). In both compounds, the bisNITPhPy and NIT-3Py-5-3Py radicals acted as pentadentate and tetradentate ligands, respectively, to connect with CuII ions, generating a 2D layer structure. The analysis of the magnetic behavior indicated that strong antiferromagnetic coupling and ferromagnetic interaction (J = 17.1 cm−1) coexisted in 1. For 2, there were ferromagnetic couplings between the CuII ion and NO group, as well as the CuII ion and radical via the pyridine ring with J1 = 32.8 and J2 = 2.2 cm−1, respectively.


2021 ◽  
Vol 03 (01) ◽  
pp. 060-066
Author(s):  
Shaofei Wu ◽  
Hoa Phan ◽  
Jing Li ◽  
Haomin Xu ◽  
Xing Li ◽  
...  

The construction of conjugated covalent organic frameworks (COFs) with strong C–C bond linkage remains a big challenge. Herein, we report a new strategy by using an oxidative C–C coupling reaction between electron-rich pyrrole rings at a liquid–liquid interface. Two threefold symmetric monomers containing three terminal pyrrole units were tested, and both gave two-dimensional conjugated COF films with good crystallinity. The bipyrrole units in the as-formed COFs are partially doped, which can be reduced to the neutral form by hydrazine and redoped by I2 vapor. The I2-doped films showed high conductivity (1.35 S/m). Meanwhile, the unpaired electrons exhibited moderate interlayer antiferromagnetic coupling.


Author(s):  
Jian-Qing Tao ◽  
Dan Mao ◽  
Jun Wang

In the title mixed-ligand metal–organic polymeric complex, {[Co(NCS)2(C8H12N6)2]·2H2O}n, the asymmetric unit contains a divalent CoIIcation, which sits on an inversion centre, two halves of two crystallographically distinct and centrosymmetric 1,4-bis(1,2,4-triazol-1-yl)butane (BTB) ligands, oneN-bound thiocyanate ligand and one solvent water molecule. The CoIIatom possesses a distorted {CoN6} octahedral geometry, with the equatorial positions taken up by triazole N atoms from four different BTB ligands. The axial positions are filled by thiocyanate N atoms. In the crystal, each CoIIatom is linked covalently to four others through the distal donors of the tethering BTB ligands, forming a neutral (4,4)-topology two-dimensional rhomboid grid layer motif, which is coincident with the (1\overline{2}1) crystal planes. Magnetic investigations show that weak antiferromagnetic coupling exists between CoIIatoms in the complex.


2002 ◽  
Vol 12 (12) ◽  
pp. 3570-3577 ◽  
Author(s):  
Paola Deplano ◽  
Laura Leoni ◽  
Maria Laura Mercuri ◽  
John A. Schlueter ◽  
Urs Geiser ◽  
...  
Keyword(s):  

2019 ◽  
Vol 75 (2) ◽  
pp. 221-230 ◽  
Author(s):  
Hongguo Hao ◽  
Hongyan Liu ◽  
Yuchen Wang ◽  
Suxian Yuan ◽  
Han Xu ◽  
...  

A series of two-dimensional (2D) coordination polymers (CPs), namely poly[[bis(μ-acetato)diaqua(μ6-biphenyl-3,3′,5,5′-tetracarboxylato)bis(N,N-dimethylacetamide)digadolinium(III)] N,N-dimethylacetamide monosolvate], {[Gd2(C16H6O8)(C2H3O2)2(C4H9NO)2(H2O)2]·C4H9NO} n (CP1), poly[[bis(μ-acetato)diaqua(μ6-biphenyl-3,3′,5,5′-tetracarboxylato)bis(N,N-dimethylacetamide)didysprosium(III)] N,N-dimethylacetamide monosolvate], {[Dy2(C16H6O8)(C2H3O2)2(C4H9NO)2(H2O)2]·C4H9NO} n (CP2), poly[bis(μ-acetato)diaqua(μ6-biphenyl-3,3′,5,5′-tetracarboxylato)bis(N,N-dimethylacetamide)dineodymium(III)], [Nd2(C16H6O8)(C2H3O2)2(C4H9NO)2(H2O)2] n (CP3), poly[bis(μ-acetato)diaqua(μ6-biphenyl-3,3′,5,5′-tetracarboxylato)bis(N,N-dimethylacetamide)disamarium(III)], [Sm2(C16H6O8)(C2H3O2)2(C4H9NO)2(H2O)2] n (CP4), has been synthesized from rigid biphenyl-3,3′,5,5′-tetracarboxylic acid under solvothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra, powder X-ray diffraction and thermogravimetric analyses, and CP1–CP4 crystallize in the monoclinic space group P21/n. CP1–CP4 are isomorphous and feature similar 2D double layers, which are further extended via interlayer hydrogen-bonding interactions into a three-dimensional (3D) supramolecular structure. Hydrogen-bonding interactions between N,N-dimethylacetamide molecules and carboxylate O atoms strengthen the packing of the layers. The organic ligands interconnect with metal ions to generate 2D layered structures with a (4,4)-connected net having {44.62} topology. CP1 has been investigated for its magnetic properties and magnetic susceptibility measurements were carried out in the range 2.0–300 K. The results of the magnetic measurements show weak antiferromagnetic coupling between the GdIII ions in CP1. Moreover, the strong luminescence of CP2 and CP4 can be selectively quenched by the Fe3+ ion and toxic solvents (e.g. acetone).


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