The magnet-like behavior can beobserved by slow relaxation of the magnetization below theblocking temperature. Since the discovery of SMMs in theearly 1990s, this assumption has formed the basis for theunderstanding of the origin of the anisotropic barrier.However, in recent years the development of novel lantha-nide-only SMMs that challenge and defy this theory pose anumber of questions:

A Polynuclear Lanthanide Single-Molecule Magnet with a Record

Molecular Nanomagnets : Fundamental Understanding

The synthesis methods, some reactions, and specific features of the structures of aryl compounds of pentavalent antimony and examples of their possible use are systematized and described on the basis of an analysis of the works published since 2009 to the present time. Some earlier works are also reviewed due to this special significance. When discussing the synthesis methods, the main attention is given to the most efficient approaches to the syntheses of the aryl compounds, for example, the reactions of ligand redistribution, substitution, and oxidative addition. The formation of heterocyclic antimony compounds is considered. The data on the biological and catalytic activities of selected antimony derivatives are presented. The bibliography consists of 318 references.

Aryl Compounds of Pentavalent Antimony: Syntheses, Reactions, and Structures

Homometallic titanium oxo clusters are one of the most important groups of metal oxo clusters, with more than 300 examples characterized by X-ray structure analyses. Most of them are uncharged and are obtained by partial hydrolysis and condensation of titanium alkoxo derivatives. The cluster cores, ranging from 3 to >50 titanium atoms, are stabilized by organic ligands. Apart from residual OR groups, carboxylato and phosphonato ligands are most frequent. The article critically reviews and categorizes the known structures and works out basic construction principles by comparing the different cluster types.

Titanium-Oxo Clusters with Bi- and Tridentate Organic Ligands: Gradual Evolution of the Structures from Small to Big.

The discovery a decade ago that individual molecules can function as magnetizable magnets provided a new, 'bottom-up' approach to nanoscale magnetic materials, and such molecules have since been called single-molecule magnets (SMMs). Each molecule functions as a nanoscale, single-domain magnetic particle that, below its blocking temperature (TB), exhibits the classical macroscale property of a magnet, namely magnetization hysteresis. In addition, they straddle the classical/quantum interface in also displaying quantum tunnelling of magnetization (QTM) and quantum phase interference, the properties of the atomic or microscale. SMMs have a number of potential applications, including very high density information storage, where each bit would be stored as the magnetization orientation of an individual molecule, and as quantum bits for quantum computing, taking advantage of the quantum superposition of states provided by the QTM. To facilitate development of techniques for addressing individual SMMs for such applications, and other reasons, it has been of interest to us to explore whether very large examples (by molecular standards) could be synthesized. In effect, can the molecular (or 'bottom-up') approach reach the size regime of the classical (or 'top-down') approach to nanoscale magnetic materials? Indeed, here we sure that a giant Mn84 SMM can be prepared with a torus structure of 4 nm dimensions, that it displays both magnetization hysteresis and QTM, and that it crystallizes as highly ordered, supramolecular nanotubes.

Giant Single-Molecule Magnets: A Mn84 Torus and its Supramolecular Nanotubes

The reaction of organobismuth precursors with trityl-H-phosphinic acid in varying reaction conditions afforded colorless crystals, whose single crystal X-ray characterization revealed the formation of monomer {(Ph3Bi)[(Ph3C)(H)PO2]2}·3/2(CH3CN)2.1/2H2O (1) and butterfly shaped tetranuclear cluster Bi4(μ3-O)2[(Ph3C)(H)(PO2)]8·2CH2Cl2·1/2CH3CN.2H2O (2). The reaction of titanium isopropoxide with two different phosphinic acids trityl-H-phosphinic acid and cycP(O)(OH) led to isolation of cubane type octahedral complex {Ti8(μ2-O)8(μ2-OH)4[(Ph3C)(H)PO2]12}[3C7H8] (3) and hexanuclear complex Ti6(μ2-cycPO2)9(μ2-O)6(μ2-OH)3·4CH3CN·4H2O (4) respectively.

Bismuth and Titanium Phosphinates: Isolation of Tetra-, Hexa- and Octanuclear Clusters

http://diposit.ub.edu/dspace/bitstream/2445/154478/1/682850.pdf

Dy2 and Dy4 hydroxo clusters assembled using o-vanillin based Schiff bases as ligands and β-diketone co-ligands: Dy4 cluster exhibits slow magnetic relaxation

Isolation and structural characterization of novel organoantimony(V)-based oxo clusters are reported. (RSb)4(OH)4(t-BuPO3)6 and (RSb)2(O)(t-BuPO3H)6 independently in the presence of pyridine under solvothermal conditions afford the hexanuclear organoantimonate clusters [(RSb)6(μ3-O)2(μ2-O)6(t-BuPO3)4], where R = p-i-PrC6H4 (1), p-ClC6H4 (2). Further, reaction of organostibonate phosphonate with Ti(OiPr)4 in the presence of pyridine under solvothermal conditions afforded the mixed-metal titanium stibonate hexanuclear clusters [(RSb)2Ti4(μ3-O)2(μ2-O)2(t-BuPO3)4(μ-OCH3)4(OCH3)4], where R = p-i-PrC6H4 (3), p-ClC6H4 (4). Band gap measurements were performed on 1-4. They reveal a remarkable reduction in the band gap on moving from the heavier main-group-based oxo cages (1 and 2) to the titanium-incorporated oxo cages (3 and 4).

Assembling Homometallic Sb6 and Heterometallic Ti4Sb2 Oxo Clusters.

The tetranuclear NiII2LnIII2 complexes, [{L'2{Ni(MeOH)(μ-OAc)}2(μ3-MeO)2Ln2}, LnIII = YIII (1), GdIII (2), TbIII (3), and DyIII (4)], were prepared using a Schiff base ligand, H3L [H3L = 3-{(2-hydroxy-3-methoxybenzylidene)amino}-2-(2-hydroxy-3-methoxyphenyl)-2,3-dihydroquinazolin-4(1H)-one, where {L'}3- is the deprotonated open structure of H3L]. X-ray crystallographic analysis of 1-4 revealed that all the complexes crystallized in the orthorhombic (Pbcn) space group, and possessed an isostructural tetranuclear butterfly or defect dicubane like core. Direct current magnetic susceptibility measurements performed on 2-4 revealed that all these complexes show an intramolecular ferromagnetic exchange coupling. Well resolved zero-field out-of-phase signals in ac magnetic susceptibility measurements were observed only in the case of 3 (Ueff = 13.4 K; τ0 = 4.1(7) × 10-7 s). This was attributed to the comparatively strong NiII-TbIII magnetic exchange coupling. DFT and ab initio calculations were carried out on 1-4 to ascertain the nature of the ferromagnetic NiII-LnIII (JNi-Ln) and LnIII-LnIII (JLn-Ln) interactions. Magnetic anisotropy and magnetic relaxation mechanisms were discussed in detail for 3 and 4. Theoretical studies provide a rationale for the slow relaxation of magnetization in 3.

Exchange-driven slow relaxation of magnetization in NiII2LnIII2 (LnIII = Y, Gd, Tb and Dy) butterfly complexes: experimental and theoretical studies.

The reactions of organoantimony(V) halides with N,O-donor ligands in presence of a base were investigated. The synthesis and crystal structure of three novel organoantimony(V) compounds $$(\hbox {Ph}_{2}\hbox {Sb})_{2}(\hbox {Q})_{2}(\hbox {O})_{2}$$
 1, (
 $$\hbox {Ph}_{3}\hbox {Sb}$$
 )(PM)Cl 2 and (
 $$\hbox {Ph}_{2}\hbox {Sb}$$
 )(TEA) 3 [where $$\hbox {Q} = \hbox {8-hydroxyquinoline}$$
 , $$\hbox {PM} = \hbox {2-pyridinemethanol}$$
 and $$\hbox {TEA} = \hbox {triethanolamine}$$
 ] are reported herein. 1 crystallizes as a dimer resulting in the formation of a four-membered $$\hbox {Sb}_{2}\hbox {O}_{2}$$
 ring while 2 and 3 are monomeric in the solid state. Interestingly, compound 3 crystallizes in orthorhombic chiral space group $$P2_{1}2_{1}2_{1}$$
 and is a rare example of spontaneous chirality exhibited in organoantimony(V) compounds. SYNOPSIS Herein we report the synthesis and structural characterization of three organoantimony(V) complexes supported by O,N donor ligands.

/pdf/investigations-on-the-reactivity-of-arylantimony-halides-2vt5sneiy9.pdf

Junaid Ali

Papers

Bismuth and Titanium Phosphinates: Isolation of Tetra-, Hexa- and Octanuclear Clusters

Dy2 and Dy4 hydroxo clusters assembled using o-vanillin based Schiff bases as ligands and β-diketone co-ligands: Dy4 cluster exhibits slow magnetic relaxation

Assembling Homometallic Sb6 and Heterometallic Ti4Sb2 Oxo Clusters.

Exchange-driven slow relaxation of magnetization in NiII2LnIII2 (LnIII = Y, Gd, Tb and Dy) butterfly complexes: experimental and theoretical studies.

Investigations on the reactivity of arylantimony halides with N,O-donor ligands