Heterometallic 3d-4f single molecule magnets

The promising potential applications, such as information processing and storage or molecular spintronics, of single-molecule magnets (SMMs) have spurred on the research of new, better SMMs. In this context, lanthanide ions have been seen as ideal candidates for new heterometallic transition metal-lanthanide SMMs. This perspective reviews 3d-4f SMMs up to 2014 and highlights the most significant advances and challenges of the field

Microwave assisted synthesis of polynuclear Ni(II) complexes

In this paper we test a solvent-free microwave assisted synthesis method with a known Ni7 complex, [Ni7(chp)12(OH)2(CH3OH)6] (2), and then extended the method to a more complex ligand system. We prepare two new trinuclear Ni(II) complexes ([Ni3(chp)4(tBuSALOH)2(MeOH)5] (4) and [Ni3(chp)4(iPrSALOH)2(MeOH)6] (5)) and report here their characterization and magnetic properties

Hexanuclear lanthanide clusters encapsulating a mu(6)-CO32- ion displaying an unusual binding mode

Reaction of hydrated lanthanum halides (Ln=La, Pr and Nd) with LH2 [1-(2-HydroxyPhenyl)-3-(2-thienyl)-1,3-Propanedione] in presence of excess triethylamine with methanol as a solvent resulted in the isolation and structural characterization of a series of novel hexanuclear lanthanide clusters templated by mu(6)-CO32- introduced via spontaneous fixation of atmospheric carbon dioxide depicting a new coordination mode of binding. This particular mode of bridging is a first report of its kind in lanthanide clusters. Magnetic analysis of the praseodymium and neodymium analogue shows strong antiferromagnetic interactions in case of praseodymium and weak antiferromagnetic interactions in case of neodymium

A new trinuclear N-N bridged Cu(II) complex with an asymmetric Schiff base ligand derived from hydrazine

In this paper we report the synthesis of an asymmetric Schiff base ligand derived from hydrazine and its Cu(II) trinuclear coordination complex, [Cu-3(HYDRAV)(2)CI2] (HYDRAV-Cu). The ligand HYDRAVH(2) and the Cu(II) complex HYDRAV-Cu have been crystallographically characterized. HYDRAVH(2) contains a fluorescent naphthyl group and emission properties of both HYDRAVH(2) and HYDRAV-Cu are reported. The magnetic properties of HYDRAV-Cu have been investigated. Hydrazine is an excellent precursor for asymmetric Schiff base ligands that afford antiferromagnetic coupling as shown here for HYDRAV-Cu. (C) 2017 Elsevier Ltd. All rights reserved

Double decker luminescent Ytterbium and Erbium SMMs with symmetric and asymmetric Schiff base ligands

Multifunctional molecules that respond both to magnetic fields and light are subject of study due to possible applications in fields as diverse as imaging or information processing and storage. In this paper we report visible and NIR emitting single-molecule magnets (SMMs) of Yb(III) and Er(III) with symmetric (SYML) and asymmetric (AZOL) Schiff base ligands. The prepared complexes SYML-Ln2 and AZOL-Ln3 (Ln = Er, Yb) are SMMs, with the exception of AZOL-Yb3, with a relaxation behavior dominated by quantum tunneling of magnetization. The multi-level double-decker structure of the complexes is ideal for surface deposition in carbon-based materials

Selective detection of Cu2+ and Co2+ in aqueous media: asymmetric chemosensors, crystal structure and spectroscopic studies

Two new azo-azomethine receptors, H2L1 and H2L2, containing hydrazine, naphthalene and different electron withdrawing groups, Cl and NO2, have been designed and synthesized for qualitative and quantitative detection of Cu2+ and Co2+ in aqueous media. The crystal structure of H2L1 is reported. The H2L1 was used as a chemosensor for selective detection of trace amount of Cu2+ in aqueous media. H2L2 was also applied to naked-eye distinction of Cu2+ and Co2+ from other transition metal ions in aqueous media. Detection limit of Cu2+ is 1.13 mu M and 1.26 mu M, in water, for H2L1 and H2L2, respectively, which are lower than the World Health Organization (WHO) recommended level. The binuclear Cu2+ and Co2+ complexes of the receptors have been also prepared and characterized using spectroscopic methods and MALDI-TOF mass analysis. Furthermore, the binding stoichiometry between the receptors upon the addition Cu2+ and Co2+ has been investigated using Job's plot. Moreover, the fluorescence emission spectra of the receptors and their metal complexes are also reported. (C) 2017 Elsevier B.V. All rights reserved

Sonochemical synthesis of two nanoscale Co(II) coordination compounds: Facile fabrication of Co3O4 nanoparticles with various morphologies

Two new nanoscale cobalt(II) coordination compounds, (adH)3[Co(Hpzdc)(pzdc)2].6H2O (1) and [Co(pzdc)2(H2O)2]n (2) (where H2pzdc is 2,3-pyrazinedicarboxylic acid and ad is adenine), were synthesized using a sonochemical process and characterized via scanning electron microscopy (SEM), X-ray powder diffraction (XRPD) and FT-IR spectroscopy. The structural characterization of 1 through single crystal X-ray diffraction revealed that it consists of a 0D coordination compound in which Co(II) ion is six-coordinated by two pzdc2- and one pzdcHligands. Compound 2 however, is a 1D coordination polymer (CP) and was found to be a perfect precursor for Co3O4 nanoparticles. Changes in the morphology and size of the nanoparticles have been induced by altering the calcination temperature in the range of 400 to 850 °C. Furthermore, the magnetic behavior of 2 was studied and compared with its single crystal counterpart

Four lanthanide-carboxylate coordination polymers with mixed 2,3-naphthalenedicarboxylate and phen ligands: syntheses, structures, luminescent and magnetic properties

Four new lanthanide-carboxylate coordination polymers of the formula [Ln3L4(phen)4(H2O)4](ClO4)·2H2O, (Ln = Dy (1), Tb (2), Ho (3) and Er (4), L = 2,3-naphthalenedicarboxylate and phen = 1,10-phenanthroline) were solvothermally synthesized. Their structures as well as magnetic and photoluminescent properties were completely investigated. Complexes 1-4 are isostructural and exhibit 1D ribbon-like chains with envelope-like sixteen-membered rings. The DyIII and TbIII complexes show the corresponding characteristic luminescence in the visible region and the ErIII complex shows luminescence in the near-infrared region upon excitation with UV rays. Studies on the magnetic properties are reported. The Dy(III) analog complex 1 exhibits slow magnetic relaxation and could be a new example of a Dy(III) SMM (single molecule magnet)

Sensitizing, sensing and chemical separation of Tb(III) ions: All in a novel T copper metal-organic framework

The importance of rare earth elements in high-tech materials has promoted the necessity to develop new materials for sensing and separating them. Luminescent metal-organic frameworks (MOFs) due to their promising applications as functional materials for chemical sensing and separation, which upon introducing analytes create multi-responsive systems, have been receiving great attention by scientists. In this regard, we have designed and synthesized a novel three-dimensional copper framework, [Cu2(3,4-pydc)2(H2O)5]n.2nH2O (1; 3,4-H2pydc = 3,4-pyridine dicarboxylic acid), in ambient condition with an interesting topology and potential application as a cation exchange material. Upon Tb3+ ions uptake, compound 1 exhibited the antenna effect to sensitize Tb3+ ions and its fluorescent emission was enhanced. It also showed selective sensing ability based on turn-on fluorescence response towards Tb3+ ions, in a mixture of main and transition metal ions and Tb3+ ions. Furthermore, the results showed that the Tb3+ ion exchange process is reversible. Therefore, compound 1 is a promising multifunctional luminescent MOF for simultaneous sensing and chemical separation of Tb3+ ions which is an advantage over the previously used MOFs in this regard. Furthermore, the reusability experiment demonstrated that 1 can be utilized for long-term detection and separation of Tb3+ ions

Magnetic molecules on surfaces: SMMs and beyond

In this critical review we cover the state of the art of surface deposition of complex magnetic molecules. Deposition methods are reviewed, as well as the most used types of surfaces, including the use of nanoparticle supports. The relevant characterization methods for molecules on surfaces are reviewed along with the molecules deposited and their most relevant examples. The perspectives of the field close the review article, the reader will get an overview of what has been done in the field of surface deposition of magnetic molecules and will acquire the tools to design their own experiments