Bivalent cobalt complexes of 2,4,6-Tri(2'-pyridyl)-1,3,5-triazine

1969 ◽  
Vol 22 (1) ◽  
pp. 141 ◽  
Author(s):  
RN Warrener ◽  
EC Watton
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Cobalt Atom ◽  
Cobalt Complexes ◽  
Octahedral Complex ◽  
Tetrahedral Coordination ◽  
Temperature Moment ◽  
Single Exception ◽  
Dimeric Form ◽  
Thermogravimetric Studies

This paper reports the isolation of a series of new coordination compounds formed with the terdentate ligand 2,4,6-tri(2?-pyridyl)- 1,3,5-triazine (tpt) and various bivalent cobalt salts. The stereochemistries of these compounds are proposed after consideration of their elementary analyses, visible solid and solution spectra, infrared spectra, magnetic moments, and thermogravimetric studies. ��� The chelates obtained include octahedral bis-complexes of the type [Co tpt2]X2 (where X = Cl, Br, I, CNS, ClO4, NO3, BF4, or BPh4) and five- coordinate mono-complexes of the type CoXz tpt (where X = Cl, Br, I, or NCS). A third dimeric form is also reported of general formula Co2X4 tpt,nH2O (where X = Cl, n = 0 or I; X = Br, n = 0 or 2). In this latter form the ligand appears to function as a composite of both terpyridine and bipyridine, showing simultaneous terdentate and bidentate behaviour, with one cobalt atom in either a five-coordinate or six- coordinate environment, and the other metal atom involved in tetrahedral coordination. ��� In general the compounds formed are high-spin with normal room- temperature magnetic moments. The single exception is the red octahedral complex [Co tpt2]Cl2, 8.5H2O, which has a room-temperature moment of only 4.0 B.M.

scholarly journals 3D Metal–Organic Frameworks Based on Co(II) and Bithiophendicarboxylate: Synthesis, Crystal Structures, Gas Adsorption, and Magnetic Properties

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1269
Author(s):  
Vadim A. Dubskikh ◽  
Anna A. Lysova ◽  
Denis G. Samsonenko ◽  
Alexander N. Lavrov ◽  
Konstantin A. Kovalenko ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Adsorption ◽  
Magnetic Moments ◽  
Bet Surface Area ◽  
Separation Performance ◽  
Bridging Ligands ◽  
Magnetization Data ◽  
Metal Organic ◽  
Ch4 Adsorption ◽  
Gas Separation Performance

Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc2−) [Co3(btdc)3(bpy)2]·4DMF, 1; [Co3(btdc)3(pz)(dmf)2]·4DMF·1.5H2O, 2; [Co3(btdc)3(dmf)4]∙2DMF∙2H2O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co3(RCOO)6}, connected either by btdc2– ligands (1, 3) or by both btdc2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N2, O2, CO, CO2, CH4 adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m2⋅g−1 and promising gas separation performance with selectivity factors up to 35.7 for CO2/N2, 45.4 for CO2/O2, 20.8 for CO2/CO, and 4.8 for CO2/CH4. The molar magnetic susceptibilities χp(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μeff (300 K) ≈ 4.93 μB. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2.

scholarly journals Structure and Properties of Ln2MoO6 Oxymolybdates (Ln = La, Pr, Nd) Doped with Magnesium

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Ekaterina Orlova ◽  
Elena Kharitonova ◽  
Timofei Sorokin ◽  
Alexander Antipin ◽  
Nataliya Novikova ◽  
...  
Keyword(s):  
Rare Earth ◽  
Infrared Spectroscopy ◽  
Room Temperature ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Spectroscopy Data ◽  
Structure And Properties ◽  
Hygroscopic Properties ◽  
Thermogravimetric Studies ◽  
Mg Doped

The literature data and the results obtained by the authors on the study of the structure and properties of a series of polycrystalline and single-crystal samples of pure and Mg-doped oxymolybdates Ln2MoO6 (Ln = La, Pr, Nd) are analyzed. Presumably, the high-temperature phase I41/acd of Nd2MoO6 single crystals is retained at room temperature. The reason for the loss of the center of symmetry in the structures of La2MoO6 and Pr2MoO6 and the transition to the space group I4¯c2 is the displacement of oxygen atoms along the twofold diagonal axes. In all structures, Mg cations are localized near the positions of the Mo atoms, and the splitting of the positions of the atoms of rare-earth elements is found. Thermogravimetric studies, as well as infrared spectroscopy data for hydrated samples of Ln2MoO6 (Ln = La, Pr, Nd), pure and with an impurity of Mg, confirm their hygroscopic properties.

Heterobimetallische 3d-4f-Komplexe mit Bis(1,2-dithiooxalato)nickelat(II) als planarem Brückenbaustein / Heterobimetallic 3d-4f-Complexes with Bis(1,2-dithiooxalato)nickelate(II) as Planar Bridging Block

2005 ◽  
Vol 60 (11) ◽  
pp. 1149-1157 ◽  
Author(s):  
Matthias Siebold ◽  
Alexandra Kelling ◽  
Uwe Schilde ◽  
Peter Strauch
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Lanthanide Ions ◽  
Water Molecules ◽  
Unit Cell Parameters ◽  
Ionic Radii ◽  
X Ray ◽  
Cell Parameters ◽  
Heterobimetallic Complexes ◽  
The Individual

Planar bis(1,2-dithiooxalato)nickelates(II) react in aqueous solutions of lanthanide ions to form pentanuclear, heterobimetallic complexes of the general composition [{Ln(H2O)n}2- {Ni(dto)2}3]・xH2O (Ln = Y3+, La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+; n = 4 or 5; x = 9 - 12). With [{Nd(H2O)5}2{Ni(S2C2O2)2}3]・xH2O (x = 10 - 12) (1) and [{Er(H2O)4}2{Ni(S2C2O2)2}3]・xH2O (x = 9 - 10) (2) we were able to isolate two complexes of this series as single crystals, which were characterized by X-ray structure analysis. Depending on the individual ionic radii of the lanthanide ions, the compounds crystallize in two different crystal systems with the following unit cell parameters: 1, monoclinic in P21/c with a = 11.3987(13), b = 11.4878(8), c = 20.823(2) Å , β = 98.907(9)° and Z = 2; 2, triclinic in P1̅ with a = 10.5091(6), b = 11.0604(6), c = 11.2823(6) Å , α = 107.899(4)°, β = 91.436(4)°, γ = 112.918(4)° and Z = 1. The channels and cavities appearing in the packing of the molecules are occupied by uncoordinated water molecules. High magnetic moments up to 14.65 BM./f.u. have been observed at room temperature due to the combined moments of the individual lanthanide ions.

scholarly journals Atran-analoge Verbindungen des Typs / Atrane Analogous Compounds of the Type

1984 ◽  
Vol 39 (3) ◽  
pp. 341-351 ◽  
Author(s):  
Joseph Grobe ◽  
Gerald Henkel ◽  
Bernt Krebs ◽  
Nikolaos Voulgarakis
Keyword(s):  
Structure Analysis ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Trigonal Bipyramid ◽  
Angular Distortion ◽  
Type I ◽  
Tetrahedral Coordination ◽  
Cage Compounds ◽  
X Ray ◽  
H Nmr

Heterocyclic cage compounds of type I (compounds 8-10) have been prepared by condensation reactions of 1,2,2-trifunctional disilanes Me(R)XSiSiMeX2 (R = Me, Ph, OEt; X = NMe2, OEt) with triethanolamine using the “Dilution Principle”. The starting compounds are obtained by Si-Me cleavage of Si2Me6 with acetylchloride/AlCl3 followed by either aminolysis with HNMe2 or alcoholysis with EtOH. 1H NMR spectra indicate N→Si(1) intraction with the more acidic Si atom in 8 and 9. This result is proved by the X-ray structure analysis of 8 (monoclinic, P21/c; a = 7,088(2), b = 15,070(4), c = 12,701(4) Å, β = 104,96(2) at -130 °C, Z = 4); the Si(1)···N distance is found to be 2,768 Å , connected with a significant angular distortion of the tetrahedral coordination around Si(1) towards a trigonal bipyramid. In compound 10, too, N→Si(1) coordination is observed at room temperature in spite of almost equal acidity for both Si atoms. This can be explained by the preference of 5- over 6-membered chelating ring systems. At higher temperatures the 1H NMR spectra show a fluctuation of the N-donor between the two Si centres.

scholarly journals Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O

2014 ◽  
Vol 70 (12) ◽  
pp. 515-518 ◽  
Author(s):  
Erik Hennings ◽  
Horst Schmidt ◽  
Wolfgang Voigt
Keyword(s):  
Phase Diagram ◽  
Room Temperature ◽  
Three Dimensional ◽  
Water Molecules ◽  
Tetrahedral Coordination ◽  
Lattice Water ◽  
Octahedral Environment ◽  
Dimensional Network ◽  
Different Types ◽  
Solid Liquid

The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2solutions is governed by coordination competition of Cl−and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+both in a tetrahedral coordination with Cl−and in an octahedral environment defined by five water molecules and one Cl−shared with the [ZnCl4]2−unit. Thus, these two different types of Zn2+cations form isolated units with composition [Zn2Cl4(H2O)5] (pentaaqua-μ-chlorido-trichloridodizinc). The trihydrate {hexaaquazinc tetrachloridozinc, [Zn(H2O)6][ZnCl4]}, consists of three different Zn2+cations, one of which is tetrahedrally coordinated by four Cl−anions. The two other Zn2+cations are each located on an inversion centre and are octahedrally surrounded by water molecules. The [ZnCl4] tetrahedra and [Zn(H2O)6] octahedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexaaquazinc tetrachloridozinc trihydrate, [Zn(H2O)6][ZnCl4]·3H2O}, consists of isolated octahedral [Zn(H2O)6] and tetrahedral [ZnCl4] units, as well as additional lattice water molecules. O—H...O hydrogen bonds between the water molecules as donor and ZnCl4tetrahedra and water molecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.

scholarly journals Optical and magneto-optical properties of GdxFe(100-x) thin films close to the compensation point

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Eva Jesenská ◽  
Takayuki Ishibashi ◽  
Lukáš Beran ◽  
Martin Pavelka ◽  
Jaroslav Hamrle ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spectral Dependence ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Perpendicular Magnetic Anisotropy ◽  
Theoretical Models ◽  
Compensation Point ◽  
Spin Torque ◽  
Dc Sputtering

Abstract Unlike ferromagnetic materials, ferrimagnetic metals have recently received considerable attention due to their bulk perpendicular magnetic anisotropy, low net magnetization and tunable magnetic properties. This makes them perfect candidates for the research of recently discovered spin-torque related phenomena. Among other ferrimagnetic metals, GdFe has an advantage in relatively large magnetic moments in both sublattices and tunability of compensation point above the room temperature by small changes in its composition. We present a systematic study of optical and magneto-optical properties of amorphous GdxFe(100-x) thin films of various compositions (x = 18.3, 20.0, 24.7, 26.7) prepared by DC sputtering on thermally oxidized SiO2 substrates. A combination of spectroscopic ellipsometry and magneto-optical spectroscopy in the photon energy range from 1.5 to 5.5 eV with advanced theoretical models allowed us to deduce the spectral dependence of complete permittivity tensors across the compensation point. Such information is important for further optical detection of spin related phenomena driven by vicinity of compensation point in nanostructures containing GdFe.

scholarly journals Tuning ferromagnetism at room temperature by visible light

2020 ◽  
Vol 117 (12) ◽  
pp. 6417-6423 ◽  
Author(s):  
Bálint Náfrádi ◽  
Péter Szirmai ◽  
Massimo Spina ◽  
Andrea Pisoni ◽  
Xavier Mettan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Ferromagnetic State ◽  
Perovskite Oxide ◽  
External Control ◽  
Digital Information ◽  
Alternative Approach ◽  
Ferromagnetic Domains ◽  
Radical Method ◽  
Oxide Perovskite

Most digital information today is encoded in the magnetization of ferromagnetic domains. The demand for ever-increasing storage space fuels continuous research for energy-efficient manipulation of magnetism at smaller and smaller length scales. Writing a bit is usually achieved by rotating the magnetization of domains of the magnetic medium, which relies on effective magnetic fields. An alternative approach is to change the magnetic state directly by acting on the interaction between magnetic moments. Correlated oxides are ideal materials for this because the effects of a small external control parameter are amplified by the electronic correlations. Here, we present a radical method for reversible, light-induced tuning of ferromagnetism at room temperature using a halide perovskite/oxide perovskite heterostructure. We demonstrate that photoinduced charge carriers from theCH3NH3PbI3photovoltaic perovskite efficiently dope the thinLa0.7Sr0.3MnO3film and decrease the magnetization of the ferromagnetic state, allowing rapid rewriting of the magnetic bit. This manipulation could be accomplished at room temperature; hence this opens avenues for magnetooptical memory devices.

scholarly journals Thio derivatives of β-diketones and their metal chelates. XX. Magnetic moments of some ruthenium(III) chelates of fluorinated Monothio-β-diketones

1975 ◽  
Vol 28 (11) ◽  
pp. 2531 ◽  
Author(s):  
SE Livingstone ◽  
JH Mayfield ◽  
DS Moore
Keyword(s):  
Room Temperature ◽  
Magnetic Moments ◽  
Metal Chelates ◽  
Magnetic Data ◽  
Derivatives Of

Magnetic data have been obtained for ruthenium(III) chelates of the fluorinated monothio-β-diketones RC(SH)=CHCOCF3 (R = 2-thienyl, β- naphthyl, Ph,p-MeC6H4, m-MeC6H4, m-ClC6H4, m-BrC6H4).The compounds are low-spin (S = 1/2) with moments in the range 1.68-1.84 B.M. at room temperature; the moments decrease with decrease in temperature.

Copper(II) Dihydroxybenzoates; Synthesis and Properties

1993 ◽  
Vol 58 (6) ◽  
pp. 1363-1370 ◽  
Author(s):  
Jozef Sokolík ◽  
Brigita Lučanská ◽  
Gustáv Plesch ◽  
Ingrid Tumová ◽  
Aladár Valent ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Electronic Spectra ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Tetragonal Distortion ◽  
High Toxicity ◽  
Antipyretic Activity ◽  
Pharmacological Screening ◽  
Cooperative Ordering

Compounds of composition Cu(2,5-DHB)2 . 4 H2O (DHB, dihydroxybenoate anion) and Cu(2,Y-DHB)2 . 8 H2O (Y = 4 or 6) were prepared as potential antiinflamatory gents with a view of pharmacological screening. The room-temperature magnetic moments allow to classify all compounds into the group of magnetically diluted copper(II) complexes. According the EPR and electronic spectra, the degree of tetragonal distortion increases passing from Cu(2,6-DHB)2 . 8 H2O (III) through Cu(2,4-DHB)2 . 8 H2O (I) to Cu(2,5-DHB)2 . 4 H2O (II. The complexes differ also in the cooperative ordering in their structures. All tested compounds exhibit higher antiinflamatory activities (on dextran edema) than free carboxylic acids. However, their effects were accompanied with relatively high toxicity. Remarkable results were also achieved on evaluating the antipyretic activity.

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