Pentanuclear heterobimetallic 3d-4f complexes of Ln2M3-type — structure and magnetism

2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Matthias Siebold ◽  
Maria Korabik ◽  
Uwe Schilde ◽  
Jerzy Mrozinski ◽  
Peter Strauch
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Powdered Sample ◽  
Temperature Dependent ◽  
Epr Spectrum ◽  
Metal Interactions ◽  
Spin Interactions ◽  
Metal Metal ◽  
Complete Series

AbstractFrom a series of pentanuclear, heterobimetallic complexes of the general composition [{Ln(H2O)n}2{Ni(dto)2}3] · xH2O, four complexes (Ln = Gd(III) with n = 4; Ln = Dy(III), Ho(III), or Er(III), with n = 5; x = 9–12; dto = 1,2-dithiooxalate) were studied due to their large magnetic moments (up to 14.65 B.M.). The magnetic properties of these complete series were measured at room temperature and the temperature dependent magnetic properties of the complexes Gd2Ni3, Dy2Ni3, Ho2Ni3, and Er2Ni3 were studied at room temperature down to 1.8 K. Whereas the intramolecular metal-metal distances were rather long (Ni1-Ni2: 11.0–11.5 Å; Ln-Ni: 6.0–6.3 Å), relatively short intermolecular metal-metal distances (Ni1-Ni2′: 3.5 Å; Er-Er′: 6.0 Å) were found in the crystal lattice, giving rise to weak intermolecular metal-metal interactions. These weak spin interactions were also supported by the EPR spectrum of a powdered sample of the diamagnetically undiluted Gd2Ni3 complex.

scholarly journals Self-assembly of alkynylplatinum(II) terpyridine amphiphiles into nanostructures via steric control and metal–metal interactions

2016 ◽  
Vol 113 (11) ◽  
pp. 2845-2850 ◽  
Author(s):  
Sammual Yu-Lut Leung ◽  
Keith Man-Chung Wong ◽  
Vivian Wing-Wah Yam
Keyword(s):  
Self Assembly ◽  
Phenylene Ethynylene ◽  
Temperature Dependent ◽  
Visible Absorption ◽  
Metal Interactions ◽  
Assembly Mechanism ◽  
Metal Metal ◽  
End Capping ◽  
Supramolecular Polymerization

A series of mono- and dinuclear alkynylplatinum(II) terpyridine complexes containing the hydrophilic oligo(para-phenylene ethynylene) with two 3,6,9-trioxadec-1-yloxy chains was designed and synthesized. The mononuclear alkynylplatinum(II) terpyridine complex was found to display a very strong tendency toward the formation of supramolecular structures. Interestingly, additional end-capping with another platinum(II) terpyridine moiety of various steric bulk at the terminal alkyne would lead to the formation of nanotubes or helical ribbons. These desirable nanostructures were found to be governed by the steric bulk on the platinum(II) terpyridine moieties, which modulates the directional metal−metal interactions and controls the formation of nanotubes or helical ribbons. Detailed analysis of temperature-dependent UV-visible absorption spectra of the nanostructured tubular aggregates also provided insights into the assembly mechanism and showed the role of metal−metal interactions in the cooperative supramolecular polymerization of the amphiphilic platinum(II) complexes.

Magnetic Properties of Compounds RE2Cu2Mg (RE = Y, La, Pr, Nd)

2003 ◽  
Vol 58 (6) ◽  
pp. 497-500 ◽  
Author(s):  
Gunter Kotzybaa ◽  
Ratikanta Mishrab ◽  
Rainer Pöttgena
Keyword(s):  
Magnetic Properties ◽  
High Frequency ◽  
Remanent Magnetization ◽  
Magnetic Transition ◽  
Magnetic Moments ◽  
Temperature Dependent ◽  
Furnace Temperature ◽  
Pauli Paramagnetism ◽  
Magnetization Behavior ◽  
Curie Temperatures

The Mo2FeB2 type magnesium intermetallics RE2Cu2Mg (RE = Y, La, Pr, Nd) were synthesized from the elements by reactions in sealed tantalum tubes in a high-frequency furnace. Temperature-dependent magnetic susceptibility measurements of Y2Cu2Mg and La2Cu2Mg indicate Pauli paramagnetism. Pr2Cu2Mg and Nd2Cu2Mg show Curie-Weiss behaviour with experimental magnetic moments of 3.67(2) μB/Pr and 3.47(2) μB/Nd, respectively. Both compounds are ordered ferromagnetically at Curie temperatures of 12.0(5) (Pr2Cu2Mg) and 43.0(5) K (Nd2Cu2Mg). Pr2Cu2Mg shows a very complex magnetization behavior with an additional magnetic transition around 2.5 T. The neodymium compound shows a pronounced square loop behavior in the magnetization at 4.5 K with a high remanent magnetization of 1.55(1) μB/Nd atom and a coercive field of 0.31(1) T.

Rare earth-rhodium-plumbides RE2Rh2Pb with RE = La–Nd, Sm, Gd and Tb

2018 ◽  
Vol 73 (12) ◽  
pp. 1015-1021 ◽  
Author(s):  
Lukas Heletta ◽  
Rainer Pöttgen
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Induction Melting ◽  
Temperature Dependent ◽  
X Ray ◽  
Conduction Electrons ◽  
Paramagnetic Behavior ◽  
Arc Melting ◽  
Intergrowth Structures

AbstractThe plumbides RE2Rh2Pb (RE = La–Nd, Sm, Gd, Tb) were synthesized in sealed niobium ampoules by induction melting of the pure elements or directly via arc-melting. The characterization of the samples by X-ray powder diffraction confirmed their Mo2B2Fe-type structure (space group P4/mbm) at room temperature. The Sm2Rh1.924Pb structure was refined from single-crystal X-ray diffractometer data: a=760.02(5), c=378.20(3) pm, wR=0.0387, 292 F2 values, 13 variables. The rhodium site shows small defects. The RE2Rh2Pb plumbides are simple 1:1 intergrowth structures of AlB2 and CsCl related slabs of compositions RERh2 and REPb. The Rh2 dumbbell in the SmRh2 slab of Sm2Rh2Pb shows a Rh–Rh distance of 281 pm. Temperature-dependent magnetic susceptibility measurements of La2Rh2Pb, Pr2Rh2Pb and Nd2Rh2Pb showed that the rhodium atoms carry no localized magnetic moments. La2Rh2Pb exhibits Pauli-paramagnetic behavior induced by the conduction electrons. The ground state of the praseodymium compound is ferromagnetic below TC=3.3 K while the neodymium compound shows a transition to an antiferromagnetic state at TN=6.1 K and a metamagnetic transition at a critical field of ca. 1000 Oe.

scholarly journals Copper(II) Halide Salts with 1-(4′-Pyridyl)-Pyridinediium

Inorganics ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 18 ◽  
Author(s):  
Jeffrey C. Monroe ◽  
Christopher P. Landee ◽  
Melanie Rademeyer ◽  
Mark M. Turnbull
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Hydrogen Bonding ◽  
Room Temperature ◽  
Crystal Packing ◽  
Monoclinic Space Group ◽  
Antiferromagnetic Exchange ◽  
Temperature Dependent ◽  
Packing Arrangement ◽  
Halide Salts

The compounds [1,4′-bipyridine]-1,1′-diium [CuCl4] (1) and [1,4′-bipyridine]-1,1′-diium [CuBr4] (2) were prepared and their crystal structures and magnetic properties are reported. The compounds are isomorphous and crystallize in the monoclinic space group C2/c. The cation crystallizes in a two-fold disordered fashion with the terminal nitrogen and carbon atoms exhibiting 50% occupancies. This results in a crystal packing arrangement with significant hydrogen bonding that is very similar to that observed in the corresponding 4,4′-bipyridinediium complexes. Temperature dependent magnetic susceptibility measurements and room temperature EPR spectroscopy indicate the presence of very weak antiferromagnetic exchange. The data were fit to the Curie–Weiss law and yielded Weiss constants of −0.26(5) K (1) and −1.0(1) K (2).

ChemInform Abstract: Magnetic Properties and Metal-Metal Interactions in Mixed-Metal (Pt2M) Trimers (M: Ni, Co).

ChemInform ◽  
1987 ◽  
Vol 18 (41) ◽  
Author(s):  
D. M. DUCKWORTH ◽  
D. M. L. GOODGAME ◽  
M. A. HITCHMAN ◽  
B. LIPPERT ◽  
K. S. MURRAY
Keyword(s):  
Magnetic Properties ◽  
Mixed Metal ◽  
Metal Interactions ◽  
Metal Metal

The magnetic properties of the Tris(2-methyl-1,10-phenanthroline)iron(II) ion

1968 ◽  
Vol 21 (1) ◽  
pp. 83 ◽  
Author(s):  
HA Goodwin ◽  
RN Sylva
Keyword(s):  
Magnetic Properties ◽  
Thermal Equilibrium ◽  
Magnetic Moments ◽  
Anomalous Behaviour ◽  
Ligand Field ◽  
Temperature Dependent ◽  
Methyl Group ◽  
Temperature Range ◽  
Effective Strength

The magnetism of the salts [Fe mephen3]X2 (X = I-, ClO4-, BF4-, PF6-; mephen = 2-methyl- 1,l0-phenanthroline) has been investigated over the temperature range c. 100-300�K. The compounds exhibit anomalous behaviour, and this has been qualitatively interpreted as being the result of the presence of nearly equi-energetic ground terms 1A1 and 5T2 of the complexed iron(11) ion, a thermal equilibrium between these terms causing the magnetic moments to be markedly temperature dependent. This behaviour is apparently the result of the sterie hindrance to the coordination of an iron(11) ion induced by the presence of the methyl group in the ligand and the consequent lowering of the effective strength of the ligand field. The colour of the salts varies with temperature, and this has been discussed in terms of π-bonding between the iron(11) ion and the ligand.

Transport and Magnetic Properties of CrO2-Polymer Magnetic Composites

2008 ◽  
Vol 47-50 ◽  
pp. 326-330
Author(s):  
Viorel Sandu ◽  
Stelian Popa ◽  
C. Plapcianu ◽  
Elena Sandu ◽  
N. Hurduc ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Methyl Methacrylate ◽  
Room Temperature ◽  
Electric Transport ◽  
Temperature Dependent ◽  
Magnetic Composites ◽  
Tunneling Model ◽  
Poly Methyl Methacrylate ◽  
High Fields ◽  
Increasing Temperature

We report the transport and magnetic properties of sintered CrO2-polymer composites. In order to improve the elastic properties of the CrO2-based composites, we investigated two types of styrene-based copolymers: poly(methyl methacrylate)-styrene (9/1 and 5/5) and linear polysiloxaneg- styrene as well as poly(methyl methacrylate)–butadiene 9/1. The electric transport and magnetoresistance are consistent with the spin tunneling model at low temperatures but the contribution of spin independent channels becomes important at high temperature and high fields. All composites display ferromagnetism at room temperature with saturation at low fields and a slightly temperature-dependent coercive field for the samples grafted either with butadiene or with styrene except for CrO2-polysiloxane-g-styrene composite where it exponentially decreases with increasing temperature.

scholarly journals Structural, Chemical and Low Temperature Magnetic Properties of Lead Free 0.6NiFe2O4 - 0.4Na0.5Bi0.5TiO3 Magnetoelectric Composite

2021 ◽  
Author(s):  
G Jegadish Kumar ◽  
M Sarathbavan ◽  
E Senthil Kumar ◽  
M Navaneethan ◽  
K Kamala Bharathi
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Saturation Magnetization ◽  
Room Temperature ◽  
Magnetization Measurement ◽  
Magnetic Interactions ◽  
Lead Free ◽  
Zero Field ◽  
Temperature Dependent ◽  
Magnetoelectric Composite

Abstract We report on structural, chemical and low temperature magnetic properties of lead free 0.6NiFe2O4 - 0.4Na0.5Bi0.5TiO3 composite. NiFe2O4 (NFO) and Na0.5Bi0.5TiO3 (NBTO) are seen to crystallize in inverse spinel and perovskite structure respectively. 0.6NiFe2O4 - 0.4Na0.5Bi0.5TiO3 composite exhibits both NFO and NBTO phases in appropriate composition. Zero field cooled (ZFC) and field cooled (FC) magnetization measurements carried out from 15 K to 300 K shows a large bifurcation at room temperature. ZFC and FC magnetization measurement exhibit a hump at Tm ⁓ 259.5 K, indicates the possible existence of competing magnetic interactions in 0.6NiFe2O4 - 0.4Na0.5Bi0.5TiO3 composite. Saturation magnetization, remanent magnetization and coercivity values are observed to increase with decreasing the temperature. Temperature dependent saturation magnetization is fit to the Bloch’s law. Magnetocrystalline anisotropy (K1) value at various temperatures are estimated and is seen to increase from 0.23 x104 erg/cc (at 300 K) to 0.34 x104 erg/cc (at 15 K).

Magnetic properties of some tridentate Schiff-base-manganese(II) complexes

1971 ◽  
Vol 24 (11) ◽  
pp. 2249 ◽  
Author(s):  
KD Butler ◽  
KS Murray ◽  
BO West
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Schiff Base ◽  
Anthranilic Acid ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Calculated Data ◽  
Exchange Integral ◽  
X Ray ◽  
Tridentate Schiff Base

A series of manganese(II) chelates of stoicheiometry [MnL] have been synthesized, where LH2 is a dibasic tridenate Schiff base formed between a 5-substituted salicylaldehyde and either a 5-substituted β- hydroxyaniline or anthranilic acid. The complexes are extremely susceptible to oxidation in solution but stable when dry. Some of the complexes were isolated as hemihydrates and others as mixed hydrate- ethanolates. Magnetic susceptibility measurements over the temperature range 80-300�K have been made for a number of the complexes. In some cases the magnetic moments at room temperature are reduced slightly from the spin-only S = 5/2 value and show θ values of c. 15-50�K. The results can be interpreted in terms of binuclear or polynuclear structures with very small values of the exchange integral J. Comparisons between observed and calculated data are not as good as those shown in related VO2+, NiII, CuII, and FeIII systems for which X-ray crystal structures are known.

The crystal, molecular structure and EPR spectrum of dipotassium bis[(μ-isothiocyanato-N,S)-(N-salicylidene-(R)-phenylalaninato)(N-salicylidene-(S)-phenylalaninato)]dicuprate(II)

1990 ◽  
Vol 55 (12) ◽  
pp. 2924-2932 ◽  
Author(s):  
Július Sivý ◽  
František Pavelčík ◽  
Juraj Krätsmár-Šmogrovič ◽  
Milan Žemlička ◽  
Valéria Seressová
Keyword(s):  
Molecular Structure ◽  
Schiff Base ◽  
Room Temperature ◽  
Complex Anion ◽  
Powdered Sample ◽  
Epr Spectrum ◽  
Apical Position ◽  
Bridging Ligands ◽  
Triclinic System ◽  
Axial Site

The title compound crystallizes in the triclinic system with a space group of P1 (No. 2); a = 0.8283(4), b = 0.9477(6), c = 1.2271(5) nm; α = 74.251(41), β = 82.351(34), γ = 70.475(40)°, V = 0.87282(74) nm3, Z = 1, F(000) = 432, μ = 1.624 mm-1, room temperature. The structure was refined to R = 0.0571 (Rw = 0.0568) for 1 920 observed reflections. The Cu(II) adopts a distorted square-pyramidal coordination. The base of the coordination polyhedron is formed by O(1), N(1), O(2) donor atoms of the terdentate Schiff-base dianion (sal-(R)-phe or sal-(S)-phe) and N(2) atom of the additional NCS- ligand. The axial site (apical position) of the pyramid is occupied by a weakly bonded S-atom; Cu-S = 0.2995(1) nm, originating from the -NCS- bridging ligands. Two units, [Cu(sal-(R)-phe)(NCS)]- and the corresponding (S)-form, are thus joined into centrosymmetric dicuprate complex anion; [Cu2(μ-isothiocyanato-N,S)2(sal-(R)-phe)(sal-(S)-phe)]2-. The Q-band EPR spectrum of this complex (powdered sample, room temperature) exhibits orthorhombic g components: gz = 2.234, gy = 2.059 and gx = 2.039 which can be interpreted as molecular ones (G = 4.9).

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