Investigation of slow magnetic relaxation in a series of 1D polymeric cyclobutane-1,1-dicarboxylates based on LnVIV2 units (Ln = Tb, Dy, Ho, Er, Tm, Yb): rare examples of V-4f single-molecule magnets.

The reactions of VOSO·3HO with Na(cbdc) (cbdc - dianion of cyclobutane-1,1-dicarboxylic acid) and lanthanide(III) nitrates taken in a molar ratio of 1 : 2 : 1 were found to yield a series of isostructural heterometallic compounds [NaLn(VO)(cbdc)(HO)] (1Ln, Ln = Tb, Dy, Ho, Er, Tm, Yb). These compounds are constructed from trinuclear anionic units [Ln(VO)(cbdc)(HO)] ({LnV}) linked by Na ions into 1D polymeric chains. The crystal structures of 1Dy and 1Er were determined by single-crystal X-ray diffraction (XRD), and their isostructurality with 1Tb, 1Ho, 1Tm, and 1Yb was proved by powder X-ray diffraction (PXRD).

Assessing the biocompatibility and stability of CeO nanoparticle conjugates with azacrowns for use as radiopharmaceuticals.

The application of nanoparticles is promising for the purposes of nuclear medicine due to the possibilities of using them as vectors and transporters of radionuclides. In this study, we have successfully synthesised conjugates of CeO nanoparticles and azacrown ligands. Then, the radiolabelling conditions with radionuclides Zn, Sc and Bi were selected and the kinetic stability of the complexes in biologically significant media was evaluated.

Lanthanide(III) SMMs with cationic and anionic complex fragments formed by a Schiff base: structure, luminescence, magnetic properties and calculations.

The syntheses, structures, luminescence and magnetic properties of a new series of Ln(III) complexes of the formula [Ln(L)(HO)(DMF)][Ln(L)] (in which HL is ,'-ethylaminebis[1-phenyl-3-methyl-4-formylimino-2-pyrazoline-5-one]; Ln(III) - Gd (1), Tb (2), or Dy (3) ions). The crystal structures were determined by single-crystal X-ray diffraction measurements for all the above-mentioned complexes. The crystals of these compounds consist of cationic [Ln(L)(HO)(DMF)] and anionic [Ln(L)] moieties which form a 3D supramolecular architecture by the H-bonds and electrostatic forces.

Inductive detection of temperature-induced magnetization dynamics of molecular spin systems.

The development and technological applications of molecular spin systems require versatile experimental techniques to characterize and control their static and dynamic magnetic properties. In the latter case, bulk spectroscopic and magnetometric techniques, such as AC magnetometry and pulsed electron paramagnetic resonance, are usually employed, showing high sensitivity, wide dynamic range, and flexibility. They are based on creating a nonequilibrium state either by changing the magnetic field or by applying resonant microwave radiation.

Novel stable ytterbium acetylacetonate-quinaldinate complexes as single-molecule magnets and surprisingly efficient luminophores.

The first Yb complexes comprising a quinoline-2-carboxylate (quinaldinate, Q) ligand, namely 1D-polymeric [Yb(acac)(Q)] (1, acac is the acetylacetonate (pentane-2,4-dionate) anion) and mononuclear [Yb(acac)(Q)(Phen)] (2, Phen is 1,10-phenanthroline), are reported. The bifunctionality of both complexes as field-induced single-molecule magnets (SMMs) and near IR luminophores has been revealed. The SMM properties of 1 and 2 have been discussed in terms of the geometry and composition of the coordination environment.

Field-Induced Slow Magnetic Relaxation in Co Cyclopropane-1,1-dicarboxylates.

New Co substituted malonate field-induced molecular magnets {[RbCo(cpdc)(HO)]∙6HO} () and [CsCo(cpdc)(HO)] () (where cpdc stands for cyclopropane-1,1-dicarboxylic acid dianions) were synthesized. Both compounds contain mononuclear bischelate fragments {Co(cpdc)(HO)} where the quasi-octahedral cobalt environment (CoO) is complemented by water molecules in apical positions. The alkali metal atoms play the role of connectors between the bischelate fragments to form 3D and 2D polymeric structures for and , respectively.

Mononuclear Transition Metal Cymantrenecarboxylates as Precursors for Spinel-Type Manganites.

Novel mononuclear cymantrenecarboxylate complexes of transition metals, [Co(HO)](CymCO)·4HO (Cym = (η-CH)Mn(CO)) (), [Ni(HO)](CymCO)·4HO (), [Zn(HO)](CymCO)·4HO (), [Co(CymCO)(imz)] (imz = imidazole, ), [Co(CymCO)(bpy)]·2PhMe (bpy = 2,2'-bipyridyl, ), [Ni(CymCO)(bpy)(HO)][CymCO]·0.5MePh·2HO (), [Cu(CymCO)(imz)] (), and [Cu(CymCO)(bpy)(HO)] (), were obtained and characterized by single-crystal X-ray analysis. Complexes - are isostructural.

Two types of LnCu hydroxo-trimethylacetate complexes with 0D and 1D motifs: synthetic features, structural differences, and slow magnetic relaxation.

Two series of heterometallic Ln-Cu compounds containing a butterfly-like tetranuclear metal core were synthesized and characterized by X-ray diffraction and magnetometry. The structures of the new compounds were shown to depend on the nature of the hydroxide used for the synthesis. The reactions of copper(II) and lanthanide(III) salts with Hpiv (Hpiv is trimethylacetic acid) and LiOH in a MeCN-EtOH mixture afford the molecular complexes [LnCu(μ-OH)(piv)(HO)]·4EtOH (1Ln, Ln = Gd, Tb, Dy, Ho, Yb), whereas the similar reactions using NaOH instead of LiOH give the 1D coordination polymers [NaLnCu(μ-OH)(piv)(EtOH)]·EtOH (2Ln, Ln = Gd, Tb, Dy, Ho, Yb).

Generation of a Hetero Spin Complex from Iron(II) Iodide with Redox Active Acenaphthene-1,2-Diimine.

The reaction of the redox active 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (dpp-BIAN) and iron(II) iodide in acetonitrile led to a new complex [(dpp-BIAN)FeI] (). Molecular structure of was determined by the single crystal X-ray diffraction analysis. The spin state of the iron cation in complex at room temperature and the magnetic behavior of in the temperature range of 2-300 K were studied using Mossbauer spectroscopy and magnetic susceptibility measurements, respectively.

Molecular and Polymer LnM (Ln = Eu, Gd, Tb, Dy; M = Zn, Cd) Complexes with Pentafluorobenzoate Anions: The Role of Temperature and Stacking Effects in the Structure; Magnetic and Luminescent Properties.

Varying the temperature of the reaction of [{Cd(pfb)(HO)}·(pfb)], [Ln(pfb)(HO)]·HO (Hpfb = pentafluorobenzoic acid), and 1,10-phenanthroline (phen) in MeCN followed by crystallization resulted in the isolation of two type of products: 1D-polymers [LnCd(pfb)(phen)]1.5MeCN (Ln = Eu (I), Gd (II), Tb (III), Dy (IV)) which were isolated at 25 °C, and molecular compounds [TbCd(pfb)(phen)] (V) formed at 75 °C. The transition from a molecular to a polymer structure becomes possible because of intra- and intermolecular interactions between the aromatic cycles of phen and pfb from neighboring tetranuclear LnCd fragments.

Mapping Magnetic Properties and Relaxation in Vanadium(IV) Complexes with Lanthanides by Electron Paramagnetic Resonance.

Vanadium(IV) complexes are actively studied as potential candidates for molecular spin qubits operating at room temperatures. They have longer electron spin decoherence times than many other transition ions, being the key property for applications in quantum information processing. In most cases reported to date, the molecular complexes were optimized through the design for this purpose.

Towards comparative investigation of Er- and Yb-based SMMs: the effect of the coordination environment configuration on the magnetic relaxation in the series of heteroleptic thiocyanate complexes.

We prepared and studied two similar series of Er and Yb thiocyanates, involving [Ln(HO)(NCS)]·HO (1Er, 1Yb) as well as the molecular and ionic complexes with 2,2'-bipyridine (bpy) and 1,10-phenantroline (phen), [Ln(HO)(bpy)(NCS)]·0.5(bpy)·HO (2Er, 2Yb), [Ln(HO)(phen)(NCS)]·phen·0.5HO (3Er, 3Yb), [Hbpy][Ln(bpy)(NCS)]·HO (4Er, 4Yb) and [Hphen][Ln(phen)(NCS)] (5Er, 5Yb).

Slow Spin Relaxation in Dioxocobaltate(II) Anions Embedded in the Lattice of Calcium Hydroxyapatite.

Pure-phase cobalt-doped calcium hydroxyapatite ceramic samples with composition Ca(PO)[(CoO)(OH)], where x = 0-0.2, were synthesized by high-temperature solid-state reaction, and their crystal structures, vibrational spectra, and magnetic properties were studied. Co atoms are found to enter into the apatite trigonal channel formally substituting H atoms and forming bent dioxocobaltate(II) anions.

Cobalt-Based Single-Ion Magnets on an Apatite Lattice: Toward Patterned Arrays for Magnetic Memories.

Single-ion magnets (SIMs) that can maintain magnetization direction on an individual transition metal atom represent the smallest atomic-scale units for future magnetic data storage devices and molecular electronics. Here we present a robust extended inorganic solid hosting efficient SIM centers, as an alternative to molecular SIM crystals. We show that unique dioxocobaltate(II) ions, confined in the channels of strontium hydroxyapatite, exhibit classical SIM features with a large energy barrier for magnetization reversal (U) of 51-59 cm.