scholarly journals Supramolecular Assemblies of Trinuclear Copper(II)-Pyrazolato Units: A Structural, Magnetic and EPR Study

Chemistry ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 626-644
Author(s):  
Kaige Shi ◽  
Logesh Mathivathanan ◽  
Radovan Herchel ◽  
Athanassios K. Boudalis ◽  
Raphael G. Raptis
Keyword(s):  
Magnetic Susceptibility ◽  
Solid State ◽  
Dft Calculations ◽  
Variable Temperature ◽  
One Dimensional ◽  
Frozen Solution ◽  
Variable Temperature Magnetic Susceptibility ◽  
Anionic Complexes ◽  
Weak Ferromagnetic ◽  
Exchange Parameters

Two anionic complexes, {[Cu3(µ3-OH)(µ-4-Ph-pz)3Cl3]2[Cu(4-Ph-pzH)4](µ-Cl)2}2− (1) and [Cu3(µ3-OH)(µ-pz)3(µ1,1-N3)2(N3)]− (2), crystallize as one-dimensional polymers, held together by weak Cu-(µ-Cl) and Cu-(µ-N3) interactions, respectively. Variable temperature magnetic susceptibility analyses determined the dominant antiferromagnetic intra-Cu3 exchange parameters in the solid state for both complexes, whereas the weak ferromagnetic inter-Cu3 interactions manifested also in the solid state EPR spectra, are absent in the corresponding frozen solution spectra. DFT calculations were employed to support the results of the magnetic susceptibility analyses.

scholarly journals A Novel Family of Triangular CoII2LnIII and CoII2YIII Clusters by the Employment of Di-2-Pyridyl Ketone

2019 ◽  
Vol 5 (2) ◽  
pp. 35 ◽  
Author(s):  
Constantinos G. Efthymiou ◽  
Áine Ní Fhuaráin ◽  
Júlia Mayans ◽  
Anastasios Tasiopoulos ◽  
Spyros P. Perlepes ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Solid State ◽  
Structural Characterization ◽  
Metal Clusters ◽  
Variable Temperature ◽  
Ac Susceptibility ◽  
Exchange Interactions ◽  
Ac Magnetic Susceptibility ◽  
Ferromagnetic Exchange ◽  
Weak Ferromagnetic

The synthesis, structural characterization and magnetic study of novel CoII/4f and CoII/YIII clusters are described. In particular, the initial employment of di-2-pyridyl ketone, (py)2CO, in mixed metal Co/4f chemistry, provided access to four triangular clusters, [CoII2MIII{(py)2C(OEt)(O)}4(NO3)(H2O)]2[M(NO3)5](ClO4)2 (M = Gd, 1; Dy, 2; Tb, 3; Y, 4), where (py)2C(OEt)(O)− is the monoanion of the hemiketal form of (py)2CO. Clusters 1–4 are the first reported Co/4f (1–3) and Co/Y (4) species bearing (py)2CO or its derivatives, despite the fact that over 200 metal clusters bearing this ligand have been reported so far. Variable-temperature, solid-state dc and ac magnetic susceptibility studies were carried out on 1–4 and revealed the presence of weak ferromagnetic exchange interactions between the metal ions (JCo-Co = +1.3 and +0.40 cm−1 in 1 and 4, respectively; JCo-Gd = +0.09 cm−1 in 1). The ac susceptibility studies on 2 revealed nonzero, weak out-of-phase (χ’’M) signals below ~5 K.

One-Dimensional Polymers Based on [{CpMo(CO)2}2(?,?2-P2)]: Solid-State Conformation Analysis by NMR Spectroscopy and DFT Calculations

2005 ◽  
Vol 11 (7) ◽  
pp. 2163-2169 ◽  
Author(s):  
Manfred Scheer ◽  
Laurence Gregoriades ◽  
Junfeng Bai ◽  
Marek Sierka ◽  
Gunther Brunklaus ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Conformation Analysis ◽  
One Dimensional ◽  
Solid State Conformation

scholarly journals Phosphonate Metal-Organic Frameworks: A Novel Family of Semiconductors

2020 ◽  
Author(s):  
Konrad Siemensmeyer ◽  
Craig A. Peeples ◽  
Patrik Tholen ◽  
Bünyemin Çoşut ◽  
Gabriel Hanna ◽  
...  
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Band Gap ◽  
Narrow Band ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
One Dimensional ◽  
Metal Organic ◽  
Copper Dimers ◽  
Electrodes For Supercapacitors

<p>Herein is reported the first semiconducting and magnetic phosphonate metal-organic framework (MOF), TUB75, which contains a one-dimensional inorganic building unit composed of a zig-zag chain of corner-sharing copper dimers. The solid-state UV-Vis spectrum of TUB75 reveals the existence of a narrow band gap of 1.4 eV, which agrees well with the 1.77 eV one obtained from DFT calculations. Magnetization measurements show that TUB75 is composed of antiferromagnetically coupled copper dimer chains. Due to their rich structural chemistry and exceptionally high thermal/chemical stabilities, phosphonate MOFs like TUB75 may open new vistas in engineerable electrodes for supercapacitors. </p>

Thiophenophane metal complexes IV. Effects from ligand changes outside the coordination sphere

1996 ◽  
Vol 74 (11) ◽  
pp. 2340-2348 ◽  
Author(s):  
C. Robert Lucas ◽  
Shuang Liu
Keyword(s):  
Magnetic Susceptibility ◽  
Variable Temperature ◽  
Cyclic Voltammograms ◽  
Ferromagnetic Coupling ◽  
X Ray ◽  
H Nmr ◽  
Variable Temperature Magnetic Susceptibility ◽  
Structural Differences ◽  
Coordination Spheres ◽  
Temperature Responses

Preparation of two thiophenophane polythioether macrocycles and 11 of their complexes of Cu(I), Cu(II), Ag(I), and Pd(II) is described. The single crystal X-ray structure of [(CuBr)2(L1)x is reported: space group Pcma, a = 8.7120(6), b = 10.7791(5), c = 12.0929(5) Å, Z = 2, Rf = 0.052, Rw = 0.036 for 521 reflections. Variable-temperature magnetic susceptibility measurements for [(CuCl2)2(L1)] and [(CuCl2)2(L2)] reveal weak antiferromagnetic and weak ferromagnetic coupling, respectively. Cyclic voltammograms of these compounds display two unequal waves in acetonitrile solvent but only one in nitromethane or dimethyl sulfoxide. 1H NMR spectra of {[(η-C3H5)Pd]2(L1)}{PF6}2 and {[(η-C3H5)Pd]2(L2)}{PF6}2 in various solvents show different temperature responses. These magnetic, electrochemical, and NMR effects are discussed in the light of structural differences at sites in the two ligands that are outside the coordination spheres. Key words: magnetic susceptibility, copper, thioether, electrochemistry.

Manganese(II) Oxazolidine Nitroxide Chelates: Structure, Magnetism, and Redox Properties

2014 ◽  
Vol 67 (11) ◽  
pp. 1618 ◽  
Author(s):  
Ian A. Gass ◽  
Mousa Asadi ◽  
David W. Lupton ◽  
Boujemaa Moubaraki ◽  
Alan M. Bond ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Intramolecular Interaction ◽  
Variable Temperature ◽  
Field Measurements ◽  
X Ray Diffraction ◽  
Magnetic Susceptibility Data ◽  
X Ray ◽  
Susceptibility Data ◽  
Variable Temperature Magnetic Susceptibility ◽  
Radical Interaction

The mononuclear oxazolidine nitroxide complex [MnII(L•)2](ClO4)2 (1) (L•, 4-dimethyl-2,2-di(2-pyridyl)oxazolidine N-oxide) has been synthesized and investigated using single-crystal X-ray diffraction, variable-temperature magnetic susceptibility measurements, and electrochemistry. The structural analysis reveals bond lengths compatible with a linear L•–MnII–L• arrangement where the ligands are in the neutral ligand form and the central MnII ion is high spin (S = 5/2). Although analysis of the variable-temperature magnetic susceptibility data suggests a strong antiferromagnetic metal–radical interaction, the radical–radical intramolecular interaction could not be determined unambiguously from such fits. The resultant isolated S = 3/2 ground state is confirmed by low-temperature magnetization versus field measurements. Electrochemical studies reveal similar square schemes and redox intermediates to the previously reported analogues [FeII(L•)2][BF4]2 and [CoII(L•)2][NO3]2.

scholarly journals The use of variable temperature 13 C solid-state MAS NMR and GIPAW DFT calculations to explore the dynamics of diethylcarbamazine citrate

2018 ◽  
Vol 57 (5) ◽  
pp. 200-210 ◽  
Author(s):  
Tiago Venâncio ◽  
Lyege Magalhaes Oliveira ◽  
Tomasz Pawlak ◽  
Javier Ellena ◽  
Nubia Boechat ◽  
...  
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Variable Temperature ◽  
Mas Nmr ◽  
Diethylcarbamazine Citrate

Synthesis, structure, photoluminescent, optical and magnetic properties of a novel thulium p-hydroxybenzenesulfonate complex

2019 ◽  
Vol 234 (3) ◽  
pp. 177-182
Author(s):  
Rong-Hua Hu ◽  
Wen-Tong Chen ◽  
Jian-gen Huang
Keyword(s):  
Magnetic Susceptibility ◽  
Solid State ◽  
Diffuse Reflectance ◽  
Magnetic Measurements ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
X Ray ◽  
Elemental Analyses ◽  
Anti Stokes

Abstract A novel thulium p-hydroxybenzenesulfonate complex [Tm(C6H5O4S)2(H2O)6](C6H5O4S)·3H2O (1) was solvothermally synthesized and characterized by elemental analyses, photoluminescence, solid-state UV/vis diffuse reflectance, magnetic measurements and single-crystal X-ray diffraction. Complex 1 features an ionic structure with the thulium ion possessing a square antiprismatic geometry. Complex 1 crystallized in the monoclinic system with space group P21. Photoluminescent measurements with solid-state sample demonstrate that the anti-Stokes emission bands in the red/NIR spectral region 710 and 812 nm are observed from the Tm3+ 4f intrashell transitions from the 3F2,3 excited states to the 3H6 and 1G4 excited state to the 3H5 state, respectively. Solid-state UV/vis diffuse reflectance spectra of complex 1 show the existence of a wide optical band gap of 3.56 eV. Variable-temperature magnetic susceptibility and field dependence magnetization measurements are also studied and the magnetic susceptibility obeys the Curie-Weiss law (χm=c/(T−θ)) with the value C being of 8.6 K and a negative Weiss constant θ being of −0.2 K.

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