Chelate complexes of molybdenum. I. Thiolo-bridged molybdenum(III) complexes with low magnetic moments

1965 ◽  
Vol 18 (10) ◽  
pp. 1549 ◽  
Author(s):  
LF Lindoy ◽  
SE Livingstone ◽  
TN Lockyer
Keyword(s):  
Magnetic Moment ◽  
Magnetic Moments ◽  
Thiol Group ◽  
Molybdenum Atom ◽  
Chelating Ligands ◽  
Chelate Complexes ◽  
Metal Interaction ◽  
Metal Metal ◽  
Multinuclear Complexes ◽  
Bridging Groups

Thiolo-bridged complexes of molybdenum(III) have been obtained from the reaction in alcohol of lithium hexachloromolybdate(III) enneahydrate with a number of chelating ligands containing a thiol group. These multinuclear complexes have three bridging groups--either three thiolo-bridges or two thiolo-bridges and one chloro-bridge-linking the molybdenum atoms which, except in one complex, are probably eight-coordinate, Only two complexes were obtained from the reaction of the ligands with potassium hexabromomolybdate(III) in alcohol. The bromo-derivatives were similar to but less stable than their chloro-analogues. All the complexes have anomalously low magnetic moments ranging from 0.3 to 1.56 BAT. per molybdenum atom, owing to metal-metal interaction either directly or via the bridging atoms. A monomeric five-coordinate molybdenum(1v) complex MoO[(PriO)2PS2]2 with a low magnetic moment (μ 0.9 B.M.) is also described.

Nitrogenous chelate complexes of transition metals. VII. Complexes of silver(I) and silver(II) with tridentate chelating ligands

1970 ◽  
Vol 23 (6) ◽  
pp. 1125 ◽  
Author(s):  
CM Harris ◽  
TN Lockyer
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Absorption Band ◽  
Magnetic Moments ◽  
Chelating Ligands ◽  
Chelate Complexes ◽  
Complex Ions ◽  
Strong Absorption Band ◽  
Stable Species ◽  
Complexes Of Transition Metals

Silver(1) complexes of 2,2',2"-terpyridine and a related Schiff base chelate 8-(or-pyridylmethyleneamino)quinoline have been prepared. They are of the type Ag(chelate)X, where X = NO3, ClO4, and PF6. Both Ag(terpy)+ and Ag(pmq)+ are stable in solution and conductance measurements have been obtained. Ag(terpy)PF6 is monomeric in nitrobenzene. Reaction of the above complex ions with pyridine or triphenylphosphine affords stable species of the form [Ag(chelate)(py)]+ and [Ag(chelate)(Ph3P)]+ which have been isolated as their perchlorate salts. Both Ag(chelate)+ and [Ag(ohelate)L]+ involve unusual stereochemistry for AgI. The known paramagnetic AgII complexes Ag(terpy)X2 (X = NO3, ClO4, �S2O8) have been reprepared. They are unstable in solution and reduce readily to AgI. They all show magnetic moments in the range 1.7-1.9 B.M. Ag(terpy)2+ in an aqueous solution of CeIv shows a strong absorption band at 470 mμ (880).

scholarly journals Spin Gapless Semiconductor–Nonmagnetic Semiconductor Transitions in Fe-Doped Ti2CoSi: First-Principle Calculations

2018 ◽  
Vol 8 (11) ◽  
pp. 2200 ◽  
Author(s):  
Yu Feng ◽  
Zhou Cui ◽  
Ming-sheng Wei ◽  
Bo Wu ◽  
Sikander Azam
Keyword(s):  
Magnetic Moment ◽  
Electronic Structures ◽  
Magnetic Moments ◽  
Total Magnetic Moment ◽  
First Principle ◽  
Half Metallic ◽  
Heusler Compound ◽  
First Principle Calculations ◽  
Metallic Ferromagnet

Employing first-principle calculations, we investigated the influence of the impurity, Fe atom, on magnetism and electronic structures of Heusler compound Ti2CoSi, which is a spin gapless semiconductor (SGS). When the impurity, Fe atom, intervened, Ti2CoSi lost its SGS property. As TiA atoms (which locate at (0, 0, 0) site) are completely occupied by Fe, the compound converts to half-metallic ferromagnet (HMF) TiFeCoSi. During this SGS→HMF transition, the total magnetic moment linearly decreases as Fe concentration increases, following the Slate–Pauling rule well. When all Co atoms are substituted by Fe, the compound converts to nonmagnetic semiconductor Fe2TiSi. During this HMF→nonmagnetic semiconductor transition, when Fe concentration y ranges from y = 0.125 to y = 0.625, the magnetic moment of Fe atom is positive and linearly decreases, while those of impurity Fe and TiB (which locate at (0.25, 0.25, 0.25) site) are negative and linearly increase. When the impurity Fe concentration reaches up to y = 1, the magnetic moments of Ti, Fe, and Si return to zero, and the compound is a nonmagnetic semiconductor.

Bis[μ-3,3′-dimethyl-3,3′-methylenebis(2,3-dihydro-1H-imidazole)]disilver(I)(Ag—Ag) dichloride hemihydrate

2006 ◽  
Vol 62 (7) ◽  
pp. m1565-m1566 ◽  
Author(s):  
Da-Qi Wang
Keyword(s):  
Title Compound ◽  
Carbene Ligands ◽  
Metal Interaction ◽  
Metal Metal ◽  
Linear Geometry

In the title compound, [Ag2(C9H12N4)2]Cl2·0.5H2O, each AgI atom is coordinated by two C atoms of two heterocyclic carbene ligands, displaying a nearly linear geometry. The Ag—Ag separation is quite long, indicating a very weak metal–metal interaction.

Studies of metal halides. Magnetic properties of some molybdenum(III) binuclear complex halides

1969 ◽  
Vol 22 (1) ◽  
pp. 121 ◽  
Author(s):  
IE Grey ◽  
PW Smith
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Binuclear Complex ◽  
Magnetic Behaviour ◽  
Metal Halides ◽  
Metal Interaction ◽  
Metal Metal ◽  
Halide Complexes

The variation of magnetic susceptibility with temperature for a number of binuclear halide complexes of molybdenum of formula A3IMo2X9 (A = Cs, Et4N, Et3NH; X = Cl, Br) has been studied over the range 90-400�K. The magnetic behaviour is consistent with that expected for magnetically isolated exchange-coupled pairs of molybdenum atoms. The coupling is interpreted as occurring mainly by direct metal-metal interaction rather than superexchange.

scholarly journals Origin of the Low Magnetic Moment in Fe2AlTi: An Ab Initio Study

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1732 ◽  
Author(s):  
Martin Friák ◽  
Anton Slávik ◽  
Ivana Miháliková ◽  
David Holec ◽  
Monika Všianská ◽  
...  
Keyword(s):  
Ab Initio ◽  
Magnetic Moment ◽  
Energy Surface ◽  
Magnetic Moments ◽  
Local Magnetic Moment ◽  
Spin Configuration ◽  
Spin Effects ◽  
Order Of Magnitude ◽  
Huge Impact ◽  
Insight Into

The intermetallic compound Fe 2 AlTi (alternatively Fe 2 TiAl) is an important phase in the ternary Fe-Al-Ti phase diagram. Previous theoretical studies showed a large discrepancy of approximately an order of magnitude between the ab initio computed magnetic moments and the experimentally measured ones. To unravel the source of this discrepancy, we analyze how various mechanisms present in realistic materials such as residual strain effects or deviations from stoichiometry affect magnetism. Since in spin-unconstrained calculations the system always evolves to the spin configuration which represents a local or global minimum in the total energy surface, finite temperature spin effects are not well described. We therefore turn the investigation around and use constrained spin calculations, fixing the global magnetic moment. This approach provides direct insight into local and global energy minima (reflecting metastable and stable spin phases) as well as the curvature of the energy surface, which correlates with the magnetic entropy and thus the magnetic configuration space accessible at finite temperatures. Based on this approach, we show that deviations from stoichiometry have a huge impact on the local magnetic moment and can explain the experimentally observed low magnetic moments.

scholarly journals Prediction of Co and Ru Nanocluster Morphology on 2D MoS2 from Interaction Energies

2021 ◽  
Author(s):  
Cara-Lena Nies ◽  
Michael Nolan
Keyword(s):  
Thin Film ◽  
Density Functional ◽  
Bulk Material ◽  
Single Layer ◽  
Metal Substrate ◽  
Single Atom ◽  
Metal Interaction ◽  
Wide Range ◽  
Metal Metal ◽  
Sulphur Vacancy

Layered materials, such as \ce{MoS2}, have a wide range of potential applications due to the properties of a single layer which often differ from the bulk material. They are of particular interest as ultra-thin diffusion barriers in semi-conductor device interconnects and as supports for low dimensional metal catalysts. Understanding the interaction between metals and the \ce{MoS2} monolayer is of great importance when selecting systems for specific applications. In previous studies the focus has been largely on the strength of the interaction between a single atom or a nanoparticle of a range of metals, which has created a significant knowledge gap in understanding thin film nucleation on 2D materials. In this paper, we present a density functional theory (DFT) study of the adsorption of small Co and Ru structures, with up to four atoms, on a monolayer of \ce{MoS2}. We explore how the metal-substrate and metal-metal interactions contribute to the stability of metal clusters on \ce{MoS2}, and how these interactions change in the presence of a sulphur vacancy, to develop insight to allow prediction of thin film morphology. The strength of interaction between the metals and \ce{MoS2} is in the order Co > Ru. The competition between metal-substrate and metal-metal interaction allows us to conclude that 2D structures should be preferred for Co on \ce{MoS2}, while Ru prefers 3D structures on \ce{MoS2}. However, the presence of a sulphur vacancy decreases the metal-metal interaction, indicating that with controlled surface modification 2D Ru structures could be achieved. Based on this understanding, we propose Co on \ce{MoS2} as a suitable candidate for advanced interconnects, while Ru on \ce{MoS2} is more suited to catalysis applications.

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