Synthesis, Structure and Magnetic Properties of Lanthanide Cluster Compounds

Synthesis, Structure and Magnetic Properties of Lanthanide Cluster Compounds
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ISBN-10 : OCLC:609904431
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Rating : 4/5 (31 Downloads)

Synopsis Synthesis, Structure and Magnetic Properties of Lanthanide Cluster Compounds by : Lucas Edward Sweet

This dissertation focuses on the exploratory synthesis of compounds that contain R6ZI12 (R= Ce, Gd, Er; Z=Mn, Fe, Co, C2) clusters with the goal of finding magnetically interesting compounds. Several new compounds were made via high temperature, solid state methods and structurally characterized using x-ray diffraction. Compounds that contain isolated clusters were studied in order to understand the magnetic coupling between lanthanide atoms. The exploration of transition metal centered clusters resulted in the discovery of two new structure types, CsR(R6CoI12)2 (R=Gd and Er) and (CeI)0.26(Ce6MnI9)2. The xray crystal structure of CsEr(Er6CoI12)2 was solved in the Pa3 0́3 space group with the cell length 18.063(2) Å at 250K (Z = 4, R1 [I>2(I)] = 0.0459). (CeI)0.26(Ce6MnI9)2 was made by combining KI, CeI3, MnI2 and Ce metal and heating to 850°C for 500 hrs. The single crystal x-ray structure for (CeI)0.26(Ce6MnI9)2 was solved in the trigonal, P3 0́3 space group with lattice parameters of a = 11.695(1) Å c = 10.8591(2) Å (Z = 2, R1 [I>2(I)] = 0.0895). The magnetic susceptibilities of hexanuclear gadolinium clusters in the compounds Gd(Gd6ZI12) (Z = Co, Fe or Mn), CaxGd1-x(Gd6MnI12) and CsGd(Gd6CoI12)2 are reported. The single-crystal structure of Gd(Gd6CoI12) and CaxGd1-x(Gd6MnI12) are reported here as well. The compound with a closed shell of cluster bonding electrons, Gd(Gd6CoI12), exhibits the effects of antiferromagnetic coupling over the entire range of temperatures measured (4 - 300 K). Clusters with unpaired, delocalized cluster bonding electrons (CBEs) exhibit enhanced susceptibilities consistent with strong ferromagnetic coupling, except at lower temperatures (less than 30 K) where intercluster antiferromagnetic coupling suppresses the susceptibilities. Four new compounds containing Gd6C2 clusters have been found: Gd6C2I11, Gd(Gd6C2I12), CsGd(Gd6C2I12)2 and Cs(Gd6C2I12). Gd6C2I11 and Cs(Gd6C2I12) crystallized in the P-1 space group while Gd(Gd6C2I12) and CsGd(Gd6C2I12)2 crystallized in the R-3 and P-3 space groups respectively. The magnetic susceptibility data for Cs(Gd6C2I12) indicate strong intracluster ferromagnetic coupling, but antiferromagnetic coupling suppresses the susceptibility below 150 K. DFT calculations on CsGd6C2I12 and molecular models indicate that the magnetic coupling between the basal Gd atoms is stronger than the magnetic coupling involving the axial Gd atoms in the distorted clusters.

Lanthanide Single Molecule Magnets

Lanthanide Single Molecule Magnets
Author :
Publisher : Springer
Total Pages : 219
Release :
ISBN-10 : 9783662469996
ISBN-13 : 3662469995
Rating : 4/5 (96 Downloads)

Synopsis Lanthanide Single Molecule Magnets by : Jinkui Tang

This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures – an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and explore new directions. Jinkui Tang is a professor at Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. Peng Zhang is currently pursuing his PhD at Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, with a specific focus on the molecular magnetism of lanthanide compounds under the supervision of Prof. Jinkui Tang.

Single-Molecule Magnets

Single-Molecule Magnets
Author :
Publisher : John Wiley & Sons
Total Pages : 448
Release :
ISBN-10 : 9783527343218
ISBN-13 : 3527343210
Rating : 4/5 (18 Downloads)

Synopsis Single-Molecule Magnets by : Malgorzata Holynska

Concise overview of synthesis and characterization of single molecule magnets Molecular magnetism is explored as an alternative to conventional solid-state magnetism as the basis for ultrahigh-density memory materials with extremely fast processing speeds. In particular single-molecule magnets (SMM) are in the focus of current research, both because of their intrinsic magnetization properties, as well as because of their potential use in molecular spintronic devices. SMMs are fascinating objects on the example of which one can explain many concepts. Single-Molecule Magnets: Molecular Architectures and Building Blocks for Spintronics starts with a general introduction to single-molecule magnets (SMM), which helps readers to understand the evolution of the field and its future. The following chapters deal with the current synthetic methods leading to SMMs, their magnetic properties and their characterization by methods such as high-field electron paramagnetic resonance, paramagnetic nuclear magnetic resonance, and magnetic circular dichroism. The book closes with an overview of radical-bridged SMMs, which have shown application potential as building blocks for high-density memories. Covers a hot topic – single-molecule magnetism is one of the fastest growing research fields in inorganic chemistry and materials science Provides researchers and newcomers to the field with a solid foundation for their further work Single-Molecule Magnets: Molecular Architectures and Building Blocks for Spintronics will appeal to inorganic chemists, materials scientists, molecular physicists, and electronics engineers interested in the rapidly growing field of study.

Polyoxometalate Chemistry for Nano-Composite Design

Polyoxometalate Chemistry for Nano-Composite Design
Author :
Publisher : Springer Science & Business Media
Total Pages : 232
Release :
ISBN-10 : 9780306479335
ISBN-13 : 0306479338
Rating : 4/5 (35 Downloads)

Synopsis Polyoxometalate Chemistry for Nano-Composite Design by : Toshihiro Yamase

"Chemists from several international polyoxometalate research groups discussed recent results, including: controlled self-organization processes for the preparation of nano-composites; electronic interactions in magnetic mixed-valence cryptands and coronands; synthesis of the novel polyoxometalates with topological or biological significance; systematic investigations in acid-base and/or redox catalysis for organic transformations; and electronic properties in materials science."--Page v

Rare Earth Coordination Chemistry

Rare Earth Coordination Chemistry
Author :
Publisher : John Wiley & Sons
Total Pages : 602
Release :
ISBN-10 : 9780470824863
ISBN-13 : 0470824867
Rating : 4/5 (63 Downloads)

Synopsis Rare Earth Coordination Chemistry by : Chun-Hui Huang

Edited by a highly regarded scientist and with contributions from sixteen international research groups, spanning Asia and North America, Rare Earth Coordination Chemistry: Fundamentals and Applications provides the first one-stop reference resource for important accomplishments in the area of rare earth. Consisting of two parts, Fundamentals and Applications, readers are armed with the systematic basic aspects of rare earth coordination chemistry and presented with the latest developments in the applications of rare earths. The systematic introduction of basic knowledge, application technology and the latest developments in the field, makes this ideal for readers across both introductory and specialist levels.

The Synthesis and Magnetochemistry of Transition and Lanthanide Metal Compounds

The Synthesis and Magnetochemistry of Transition and Lanthanide Metal Compounds
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Publisher :
Total Pages :
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ISBN-10 : OCLC:1064459602
ISBN-13 :
Rating : 4/5 (02 Downloads)

Synopsis The Synthesis and Magnetochemistry of Transition and Lanthanide Metal Compounds by : Charlene Amanda Smith

The introductory Chapter to this thesis outlines fundamental aspects of 4f lanthanide(III) coordination chemistry, in particular compounds that possess the intriguing properties of slow relaxation of magnetisation, (or the ability to behave as single-molecule magnets, SMMs). The recent renaissance into the study of the magnetic behaviour of 4f-coordination complexes has led to the consideration of utilising organometallic precursors for the development of novel lanthanide containing compounds, which may possess interesting magnetic properties, subsequently forming the basis of Chapter Two. In Chapter Two, the syntheses and structures of the novel lithiated thiolate ligand, lithium triphenylsilylthiolate, (Ph3SiS-Li) (2.1), and the sulfur-bridged, dimetallic dysprosium(III) and gadolinium(III) complexes [(MeCp)2Dy(μ-SSiPh3)]2 (2.2) and [(MeCp)2Gd(μ-SSiPh3)]2 (2.3), are described in detail. The structural and physical properties of these compounds are analysed through NMR, elemental analysis and SQUID magnetometry, alongside supporting theoretical calculations to reveal that compound 2.2 is the first dimetallic, sulfur-bridged SMM reported, giving an energy barrier to the reversal of magnetisation of Ueff = 192 ± 5 K.56bChapter Three reports on the structural development of a series of lanthanide monomers, exhibiting the general motif [Ln(OSiPh3)3(THF)3] (where Ln = Dy(3.4), Er(3.5), Ho(3.6), Gd(3.7), Tb(3.8)), exploiting the siloxide ligand Ph3SiOH through two novel synthetic routes. This Chapter also provides new analytical insight to these complexes by exploring their magnetic properties through a series of SQUID measurements and through the analysis of their electronic properties using air sensitive, variable temperature optical absorption spectroscopy. Compounds 3.4 and 3.5 were revealed to be SMMs, with 3.5 having a much higher thermal barrier to the reversal of magnetisation, Ueff = ~ 28 K, than 3.4, which are supported by theoretical analysis. Chapter Four describes the utility of ligand 2.1 and Ph3SiOH in the context of 3d transition metal cyclopentadienyl chemistry, outlining the syntheses and structures of three distinct compounds; the trimetallic, [Cp2Mn3(μ-OSiPh3)4](4.7), the hetero-cubane tetramer [CpMn(μ-SSiPh3)]4 (4.8) and the dimetallic thiolate-bridged [CpCr(μ-SSiPh3)]2 (4.9) compound. These compounds were formed in reactions exploiting organometallic manganocene and chromocene precursors. Magnetic susceptibility measurements were conducted on these compounds to gain further insight into their structural properties. The magnetic exchange coupling constants for Mn(II) compounds 4.7 and 4.8 were J = - 4.4 cm-1 and J = - 3.0 cm-1 respectively. Furthermore, having demonstrated the use of metal-cyclopentadienyl building blocks in the synthesis of novel SMMs, Chapter Five discusses the possibility of further advancement on the development of this class of magnetic molecules.

Lanthanide-Based Multifunctional Materials

Lanthanide-Based Multifunctional Materials
Author :
Publisher : Elsevier
Total Pages : 492
Release :
ISBN-10 : 9780128138410
ISBN-13 : 0128138416
Rating : 4/5 (10 Downloads)

Synopsis Lanthanide-Based Multifunctional Materials by :

Lanthanide-Based Multifunctional Materials: From OLEDs to SIMs serves as a comprehensive and state-of the art review on these promising compounds, delivering a panorama of their extensive and rapidly growing applications. After an introductory chapter on the theoretical description of the optical and magnetic behaviour of lanthanides and on the prediction of their properties by ab-initio methods, four chapters are devoted to lanthanide-based OLEDs, including the latest trends in visible emitters, the emerging field of near infrared emitters and the first achievements attained in the field of chiral OLEDs. The use of lanthanide complexes as molecular magnets spreads over another two chapters, which explain the evolution of 4f-elements-based SIMs and the most recent advances in heterometallic 3d–4f SMMs. Other very active research areas are covered in the remaining five chapters, dedicated to lanthanide-doped germanate and tellurite glasses, luminescent materials for up-conversion, luminescent thermosensors, multimodal imaging and therapeutic agents, and chemosensors. The book is aimed at academic and industrial researchers, undergraduates and postgraduates alike, and is of particular interest for the Materials Science, Applied Physics and Applied Chemistry communities. Includes the latest progress on lanthanide-based materials and their applications (in OLEDs, SIMs, doped matrices, up-conversion, thermosensors, theragnostics and chemosensors) Presents basic and applied aspects of the Physics and Chemistry of lanthanide compounds, as well as future lines of action Covers successful examples of devices and proofs-of-concept and provides guidelines for the rational design of new materials