Anomalous magnetism of iron(II) complexes of methyl-substituted pyridylthiazoles

1972 ◽  
Vol 25 (4) ◽  
pp. 715 ◽  
Author(s):  
HA Goodwin ◽  
DW Mather
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
High Spin ◽  
Metal Atom ◽  
Electronic Spectra ◽  
Chelating Agents ◽  
Strong Dependence ◽  
Chelating Agent ◽  
Crossover Region ◽  
Field Strengths

Bis-ligand iron(11) and nickel(11) complexes of the potentially tridentate chelating agents 2-(3-methyl-2-pyridylamino)-4-(2-pyridyl)thiazole and 2-(4-methyl- 2-pyridylamino)-4-(2-pyridyl)thiazole are described. The electronic spectra of the nickel(11) complexes show that the field strengths of the ligands are in the neighbourhood of the Crossover region for iron(11). The magnetic properties of the cationic iron(11) complexes are anomalous and consistent with a spin-equilibrium involving the nearly equi-energetic 5T2 and 1A1 states of the metal atom. The magnetism shows a strong dependence on the associated anion. 2-(6-Methyl-2-pyridylamino)-4- (2-pyridyl)thiazole is also described. In its bis-ligand iron(11) complexes it functions as a bidentate chelating agent and the complexes are high-spin. All three ligands may be deprotonated to yield inner complexes with iron(11) which in some instances have anomalous magnetic properties associated with the presence of a spin-equilibrium. 2-(6-Methyl-2-pyridyl)-4-(2-pyridyl)thiaole and its bis-ligand iron(11) and nickel(11) complexes are also described. The iron(11) complexes are high-spin and show normal temperature dependence of their magnetism.

Metal complexes of 1,10-phenanthroline derivatives. X. 5T2 ↔ 1A1 transitions in iron(II) complexes of 2-(1,10-Phenanthrolin-2-yl)imidazole derivatives

1975 ◽  
Vol 28 (3) ◽  
pp. 505 ◽  
Author(s):  
DW Mather ◽  
HA Goodwin
Keyword(s):  
Metal Complexes ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Chelating Agents ◽  
Elevated Temperatures ◽  
Magnetic Moments ◽  
Spin Transition ◽  
Benzimidazole Derivative ◽  
Crossover Region ◽  
Experimental Temperature Range

The preparation of the tridentate chelating agents 2-(1,10- phenanthrolin-2-yl)imidazoline and 2-(1,10-phenanthrolin-2- yl)benzimidazole and their bis-ligand complexes with iron(II) and nickel(II) is described. The latter ligand coordinates as either a neutral or anionic tridentate. Data from the spectra of the nickel(II) complexes indicate that the ligands have field strengths in the iron(II) crossover region. The temperature dependence of the magnetism of the imidazoline iron(II) complex reveals a gradual, temperature- induced 5T2 ↔ 1A1 transition which is not complete within the experimental temperature range (83-363 K). Both the cationic and neutral iron(II) complexes of the benzimidazole derivative are essentially low-spin at room temperature but a significant increase in their magnetic moments at elevated temperatures indicates that a spin transition may be occurring in these compounds too.

Sulphur-nitrogen chelating agents. VII. Five- and six-coordinate complexes of cobalt(II), nickel(II), and copper(II) with an S-N-S tridentate ligand

1969 ◽  
Vol 22 (9) ◽  
pp. 1817 ◽  
Author(s):  
SE Livingstone ◽  
JD Nolan
Keyword(s):  
High Spin ◽  
Electronic Spectra ◽  
Copper Complexes ◽  
Chelating Agents ◽  
Nickel Complexes ◽  
Tridentate Ligand ◽  
Octahedral Complex ◽  
Halide Complexes

Mono-ligand complexes of the tridentate ligand N-(2-methylthiophenyl)- 2?-methylthiophenylmethyleneimine (SNS) of the type MX2(SNS) (M = Co, Ni, Cu; X = Cl, Br, I, or FCS) have been prepared. The electronic spectra indicate that the cobalt halide complexes are five-coordinate, whereas the complex Co(NCS)2- (SNS) and the nickel complexes are six- coordinate and polymeric. The copper complexes CuX2(SNS) (X = Cl, Br) are possibly five-coordinate. ��� The bis-complexes of nickel [Ni(SNS)2]X2 (X = ClO4, BF4) are high- spin but the complex [Co(SNS)2](ClO4)2 appears to be a rare example of a low-spin octahedral complex of cobalt(II).

Metal complexes of 1,10-phenanthroline derivatives. IX. 5T2 ↔ 1A1 spin transitions in iron(II) complexes of 2-(1,10-phenanthrolin-2-yl)thiazole derivatives

1975 ◽  
Vol 28 (1) ◽  
pp. 33 ◽  
Author(s):  
HA Goodwin ◽  
DW Mather ◽  
FE Smith
Keyword(s):  
Metal Atom ◽  
Chelating Agents ◽  
Spin Transition ◽  
Nickel Complexes ◽  
Close Approach ◽  
Crossover Region ◽  
Thiazole Derivatives ◽  
Pyridyl Group ◽  
Spin Pairing ◽  
Experimental Temperature Range

The preparation of the tridentate chelating agents 2-(1,10- phenanthrolin-2-yl)thiazole, 2-(1,10-phenanthrolin-2-yl)-4-(2- pyridyl)thiazole 2-(1,10-phenanthrolin-2-yl)thiazolidine and 2-(1,10- phenanthrolin-2-yl)benzothiazole is described. Data from the spectra of the bis-ligand nickel complexes indicate that the ligands all have field strengths in the iron(II) crossover region. The temperature dependence of the magnetism of the bis-ligand iron(II) complexes reveals that, except for the complexes of the pyridylthiazole, a smooth, temperature-induced 5T2 ↔ 1A1 transition occurs in these compounds. For no complex is the transition complete within the experimental temperature range (83-363 K). The complex of the pyridylthiazole is high-spin throughout the range, the uncoordinated pyridyl group hindering the close approach of ligand and metal atom necessary for spin-pairing. The ability of the other ligands to induce a spin transition is primarily a consequence of distortions in the environment about the metal atom arising from coordination of the five- membered thiazole or related ring.

scholarly journals Study on the Behavior and Removal of Cadmium and Zinc Using Taraxacum officinale and Gazania under the Application of Biodegradable Chelating Agents

2021 ◽  
Vol 11 (4) ◽  
pp. 1557
Author(s):  
Naoki Kano ◽  
Takumi Hori ◽  
Haixin Zhang ◽  
Naoto Miyamoto ◽  
David Eva Vanessa Anak ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Chelating Agents ◽  
Environmental Control ◽  
Chelating Agent ◽  
Taraxacum Officinale ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Experimental Treatments ◽  
The One

The removal of cadmium (Cd) and zinc (Zn) from soil by phytoremediation was investigated using Taraxacum officinale and Gazania. A plant environmental control system was used to cultivate the plants. The effects of different biodegradable chelating agents (i.e., EDDS, HIDS, and GLDA), relative humidity, and other competitive metals on the adsorption of Cd and Zn were also studied. In addition, the approach for metal recovery was explored by extraction of metals from plants after phytoremediation using Gazania. The concentrations of Cd and Zn were determined by inductively coupled plasma mass spectrometry (ICP-MS). In addition, one-way analysis of variance (ANOVA) tests were performed.to determine significant differences between the experimental treatments adopted in this work. Consequently, the following main conclusions were obtained: (1) In the case of Taraxacum officinale, Cd and Zn could be removed even under the presence of other heavy metals. (2) By adding a chelating agent, the amount absorbed by the shoot generally increased. (3) In the case of Gazania, the concentration of Cd was higher in root than that in shoot, whereas the concentration of Zn was higher in the shoot than that in the root. (4) Taraxacum officinale was more suitable for phytoremediation of Cd than Gazania. (5) Cd and Zn could be extracted from plants by adding a low concentration of nitric acid. (6) The one-way ANOVA tests showed no statistically significant differences among the experimental treatments.

Effects of Ta2O5 addition on the microstructure and temperature dependence of magnetic properties of MnZn ferrites

2009 ◽  
Vol 321 (5) ◽  
pp. 438-441 ◽  
Author(s):  
Lezhong Li ◽  
Zhongwen Lan ◽  
Zhong Yu ◽  
Ke Sun ◽  
Ming Luo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Mnzn Ferrites

High-spin tetranuclear iron(III) grids: Synthesis, crystal structure and magnetic properties

Polyhedron ◽  
2013 ◽  
Vol 52 ◽  
pp. 970-975 ◽  
Author(s):  
Yi-Tong Wang ◽  
Ai-Li Cui ◽  
De-Zhong Shen ◽  
Hui-Zhong Kou
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
High Spin
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