Self-assembly of quaterpyridine ligands and Cu+ cation into helical complexes of 2:2 stoichiometry under electrospray ionisation conditions

Yellow-to-brown and yellow-to-green electrochromic devices based on complexes of transition metal ions with a triphenylamine-based ligand

Transmissive-to-colored electrochromism has been achieved by combination of MLCT of transition metal complexes with the electrochromic properties of ligand molecules. The color transitions were from yellow to dark brown for the Fe(ii) complex, yellow to orange to bluish-green for the Co(ii) complex and yellow to green for the Zn(ii) complex. By using a metal ion-ligand coordination approach, the self-assembly of hydrazone-based ligands containing a triphenylamine group with appropriate metal salts (FeCl2, Co(ClO4)2 and Zn(BF4)2) produced novel complexes of the general formula [ML2]X2. The isolated complexes were characterized by spectroscopic methods, and the Co(ii) complex also by X-ray diffraction analysis. Thin films of the complexes have been obtained by a spray-coating method and they were used in the construction of electrochromic devices, which showed good electrochromic stability, a high color contrast of 47.5% for Fe(ii), 37.2% for Co(ii) and 33.7% for Zn(ii) complexes and fast coloring and bleaching times.

Full characterization and cytotoxic activity of new silver(i) and copper(i) helicates with quaterpyridine

DNA binding and cells' cycle disorders caused by four new dinuclear Ag(i) and Cu(i) double helicates with quaterpyridine ligands.

Copper complexes formed by 3,5-bis(2,2′-bipyridin-4-ylethynyl)benzoic acid and its methyl and ethyl esters as studied by electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry was used to study the complexes of ligands containing two bipyridine units, namely 3,5-bis(2,2-bipyridin-4-ylethynyl)benzoic acid (1) and its methyl and ethyl esters (2, 3), with copper cation, with CuCl2 as a source of copper. It was found that the type of complexes formed strongly depends on CuCl2 concentration. At lower CuCl2 concentration, the detected complexes were rather simple and some of them were formed upon electrospray ionization conditions e.g. ions [22+Cu2]2+ and [32+Cu2]2+ (complexes ligand-Cu(I) of stoichiometry 2:2) which are analogical to the well known, for quaterpyridine, helical complexes. At higher CuCl2 concentration, the detected complexes were more complicated, and most of them contained copper cations bridged by chlorides. The largest ions were [L2+Cu4Cl6]2+. The CID MS/MS spectra of these ions allowed determination of their mass spectrometric fragmentation pathways and as a consequence their structure elucidation.

Complexation of lanthanides, actinides and transition metal cations with a 6-(1,2,4-triazin-3-yl)-2,2':6',2''-terpyridine ligand: implications for actinide(III)/lanthanide(III) partitioning

The quadridentate N-heterocyclic ligand 6-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2' : 6',2''-terpyridine (CyMe(4)-hemi-BTBP) has been synthesized and its interactions with Am(III), U(VI), Ln(III) and some transition metal cations have been evaluated by X-ray crystallographic analysis, Am(III)/Eu(III) solvent extraction experiments, UV absorption spectrophotometry, NMR studies and ESI-MS. Structures of 1:1 complexes with Eu(III), Ce(III) and the linear uranyl (UO(2)(2+)) ion were obtained by X-ray crystallographic analysis, and they showed similar coordination behavior to related BTBP complexes. In methanol, the stability constants of the Ln(III) complexes are slightly lower than those of the analogous quadridentate bis-triazine BTBP ligands, while the stability constant for the Yb(III) complex is higher. (1)H NMR titrations and ESI-MS with lanthanide nitrates showed that the ligand forms only 1:1 complexes with Eu(III), Ce(III) and Yb(III), while both 1:1 and 1:2 complexes were formed with La(III) and Y(III) in acetonitrile. A mixture of isomeric chiral 2:2 helical complexes was formed with Cu(I), with a slight preference (1.4:1) for a single directional isomer. In contrast, a 1:1 complex was observed with the larger Ag(I) ion. The ligand was unable to extract Am(III) or Eu(III) from nitric acid solutions into 1-octanol, except in the presence of a synergist at low acidity. The results show that the presence of two outer 1,2,4-triazine rings is required for the efficient extraction and separation of An(III) from Ln(III) by quadridentate N-donor ligands.

Binuclear copper complexes with non-steroidal anti-inflammatory drugs as studied by electrospray ionization mass spectrometry

The solutions containing one of the copper salts (CuCl2, Cu(ClO4)2, Cu(NO3)2, and CuSO4) and one of the non-steroidal anti-inflammatory drugs (NSAIDs, ibuprofen, ketoprofen or naproxen) were analyzed by electrospray ionization mass spectrometry. Three of the salts, namely CuCl2, Cu(ClO4)2 and Cu(NO3)2, yielded binuclear complexes of drug:metal stoichiometry 1:2. Existence of the complexes of such stoichiometry has not been earlier observed. For copper(II) chloride the complexes (ions of the type [M-HCOOH+Cu2Cl]+ and [M+Cu2Cl]+, M stands for the drug molecule) were formed in the gas phase. When copper(II) perchlorate or copper(II) nitrate was used, the observed binuclear copper complexes (ions of the type [M-H+Cu2(ClO4)2+CH3OH]+, [M-H+Cu2(ClO4)2]+ and [M-H+Cu2(NO3)2+CH3OH]+, [M-H+Cu2(NO3)2]+) were observed at low cone voltage, thus these complexes must have already existed in the solution analysed. Therefore, such complexes may also exist under physiological conditions.

Unexpected formation of complexes between protonated organic ligand and neutral salt molecule studied by electrospray ionization mass spectrometry

Protonated organic ligands containing pyridine moieties form complexes with undissociated salt molecules present in solution, especially with ZnCl(2), as proved by electrospray ionization mass spectrometry. In the gas phase, the ions observed, for example [L1H + ZnCl(2)](+), lose an HCl molecule producing ions [L1 + ZnCl](+) (L1 = 1,1,3,3-Tetramethyl-1,3-bis(3-(3-(2-pyridyl)propoxy)propyl)disiloxane). The use of other zinc salts (for example ZnI(2)), also yielded the complexes of between protonated ligands and neutral salt molecules (for example, [L1H + ZnI(2)](+)), but losses of respective acid molecules (for example, HI), proceeded with higher efficiencies than the loss of HCl molecule. An increase in solvent polarity, namely the use of water instead of methanol, led to the substantial lowering of [L1H + ZnCl(2)](+) ion abundances, since fewer undissociated species (for example, ZnCl(2)) were present in the solution. Ligand L2 (1,3,5,7-tetramethyl-1,3,5,7-tetrakis(3-(3-(2- pyridyl)propoxy)propyl)cyclotetrasiloxane, larger than L1), forms doubly charged ions containing one and two ZnCl(2) molecules, for example [L1H(2) + ZnCl(2)](+2).