An electrospray ionization mass spectrometric study of beryllium chloride solutions and complexes with crown ether and cryptand macrocyclic ligands

Triangulo-{ErIII 3} complex showing field supported slow magnetic relaxation

The triangulo-{Er3} complex [Er3Cl(o-van)3(OH)2(H2O)5]Cl3·nH2O (n = 9.4; H(o-van) = o-vanillin) (1) was generated by an in situ method. The isolated Er(iii) complex 1 was characterized by elemental analysis and molecular spectroscopy. The results of single crystal X-ray diffraction studies have shown that 1 is built up of trinuclear [Er3Cl(o-van)3(OH)2(H2O)5]3+ complex cations, chloride anions and water solvate molecules. Within the complex cation the three Er(iii) central atoms are placed at the apexes of a triangle which are bridged by three (o-van)- ligands with additional chelating functions and two μ3-OH- ligands. Additionally five aqua and one chlorido ligands complete the octa-coordination of the three Er(iii) atoms. AC susceptibility measurements reveal that the compound exhibits slow magnetic relaxation with two relaxation modes.

Dinuclear Dysprosium Schiff base complex showing slow magnetic relaxation in the absence of an external magnetic field

A dinuclear dysprosium(III) complex [Dy2(NO3)3(L)3]•nCH3OH (n = 1.20; HL = (2-[(2-hydroxy-propylimino)methyl]phenol)) (1) was isolated when the dysprosium nitrate reacted with a solution of salicylaldehyde and 1-amino-2-propanol in basic medium under...

Quinolino[7,8-h]quinoline: a 'just right' ligand for beryllium(II) coordination

We report the synthesis and crystal structure of the first quinolino[7,8-h]quinoline beryllium(II) complex of the general formula [BeL2(MeCN)Br]Br·MeCN, containing the ligand 4,9-dihydroxyquinolino[7,8-h]quinoline (L2). The Be(II) cation is a great size match for the dinitrogen binding pocket of the quinolino[7,8-h]quinoline ligand as indicated by minimal out-of-plane displacement and ligand distortion parameters.

Interaction of aflatoxin G1 with free DNA in vitro and possibility of its application in removing aflatoxin G1

The present study sought to evaluate the interaction between aflatoxin G₁ and free DNA in vitro through different analytical techniques. The UV-visible spectra results showed that the structure of DNA might be changed with a new aflatoxin G₁-DNA complex forming, which indicated that the interacting mode between them was the intercalating mode. The DNA melting temperature increased by 12.80 °C, suggesting that the DNA double helix structure was more compact and stable through intercalation. The circular dichroism (CD) spectra results indicated that the interaction of aflatoxin G₁ with DNA induced the DNA base stacking changes. The results of agarose gel electrophoresis and fluorescence microscope further verified that the interacting mode between aflatoxin G₁ and DNA was intercalation mode. According to the fluorescence spectrum data, the binding constant was calculated 6.24 × 10⁴ L·mol^-1. The thermodynamic results demonstrated that the reaction of aflatoxin G₁ intercalating to DNA was a spontaneous reaction. The elimination results suggested that aflatoxin G₁ could be enriched and removed by DNA intercalation through magnetic beads separation, with the removal efficiency of 93.73%. The study results would provide a theoretical basis for establishing a new aflatoxin removal method based on DNA intercalation.

Ethylenediamine complexes of the beryllium halides and pseudo-halides

The suitability of ethylenediamine (en) as an alternative solvent to liquid ammonia in beryllium chemistry was evaluated. Therefore, BeF2, BeCl2, BeBr2, BeI2, [Be(NH3)4](N3)2, [Be(NH3)4](CN)2 and [Be(NH3)4](SCN)2 were reacted with ethylenediamine and analysed via NMR and IR spectroscopy. Additionally single crystal structures of [BeF2(en)]n, [Be(en)3]Cl2, [Be(en)3]Br2, [Be(en)2]I2·en, [Be(en)2](N3)2·en, [Be(en)2]4(SCN)7Cl and [Be3(OH)3(en)3][C2H9N2](SCN)4 were obtained. The anions were found to have a distinct influence on the solubility as well as on the species present in solution and the solid state, while ethylenediamine can act as mono- and bidentate ligand or as a crystal solvent.

Behavior of beryllium halides and triflate in acetonitrile solutions

The solution behavior of beryllium halides and triflate in acetonitrile was studied by NMR, IR and Raman spectroscopy. Thereby mononuclear units [(MeCN)2BeX 2] (X = Cl, Br, I, OTf) were identified as dominant species in these solutions. The solid state structure of [(MeCN)2Be(OTf)2] has been determined by X-ray diffraction. If only one equivalent of MeCN is used the dinuclear compounds [(MeCN)BeX 2]2 (X = Cl, Br, I) are formed. Partial halide and triflate dissociation into the monomeric complexes as well as the formation of hetero-halide complexes [(MeCN)2BeClBr], [(MeCN)2BeClI] and [(MeCN)2BeBrI] was observed.

Coordination chemistry of Be2+ ions with chelating oxygen donor ligands: further insights using electrospray mass spectrometry

The electrospray ionisation mass spectrometric (ESI-MS) behaviour of various complexes of beryllium have been investigated in the work described in this paper. These beryllium complexes were analysed in situ on a small scale by preparing appropriate molar mixtures of the Be2+ ion with ligands in a range of solvent systems. In view of the toxicity of beryllium compounds, this combinatorial type screening, involving miniscule amounts of material in solution, proved to be a safe strategy to pursue the coordination chemistry of beryllium. A variety of beryllium complexes were generated with various ligands in solutions and subjected to detailed characterisation by ESI-MS. These ligands, containing functional groups or architecture of interest, varied from simple ligands such as the acetate ion to more common beryllium chelators including hydroxy keto ligands (maltol, tropolone), malonic acid, chromotropic acid and citric acid. Generally, there was excellent correlation between the species observed in the mass spectrum and those confirmed to exist in solution by other techniques. This lent strong credence to the ESI-MS methodology used as an efficient analytical technique for the easy screening of a diverse range of potential ligands for the divalent beryllium ion.

Beryllium coordination chemistry and its implications on the understanding of metal induced immune responses

The coordination chemistry of beryllium with ligands containing biologically relevant functional groups is discussed. The geometry, speciation and reactivity of these compounds, aids a better understanding of metal ion induced immune reactions.