Gas-phase oxidation and reduction of some 1-(2-benzothiazolyl)-3,5-diphenyl formazans. Complex formation with transition metals under laser desorption ionization

Nuutinen, Jari; Romppanen, Ritva; Mäkinen, Silja K.; Vainiotalo, Pirjo

doi:10.1016/s1044-0305(98)00161-5

Cited by 5 publications

(8 citation statements)

References 29 publications

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“…Several matrices were tested in MALDI measurements with the resorcarenes: 1‐(2‐benzothiazolyl)‐3‐(4‐methoxyphenyl)‐5‐phenylformazan (BMOF),16 2.5‐dihydroxybenzoic acid (DHB),17 1,8,9‐trihydroxyanthracene (dithranol),18 2‐(4‐hydroxyphenylazo)benzoic acid (HABA),19 9‐nitroanthracene (9‐NA),20 and 2,4,6‐trihydroxyacetophenone (THAP) 21. The matrix and the sample were mixed in a molar ratio of 200:1 before placing the mixture onto the sample plate.…”

Section: Methodsmentioning

confidence: 99%

Mass spectrometric studies of benzoxazine resorcarenes

Hakala

Nuutinen

Straub

et al. 2002

Rapid Comm Mass Spectrometry

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Eleven differently substituted 3,4-dihydro-2H-1,3-benzoxazine resorcarenes were studied by electrospray ionisation (ESI) and matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry, using Fourier transform ion cyclotron resonance (FT-ICR) and time-of-flight (TOF) mass spectrometers, respectively. Under ESI conditions it was possible to transfer the intact resorcarenes from solution to the gas phase, yielding [M + H](+) and [M + 2H](+) ions as the main ions observed. Energy increase of the ions induced ready decomposition through successive eliminations of four CH(2)NR groups. Ion-molecule reactions showed that the ionising proton was situated somewhere inside the molecule and could not be reached with neutral reagent gases. In the host-guest complexation experiments, the benzoxazine resorcarenes studied turned out to be poor hosts for alkali metal and ammonium ions. In MALDI experiments, 2,5-dihydroxybenzoic acid proved to be the best matrix for these compounds. However, the intensity of the [M + H](+) ions was low for all compounds, and extensive fragmentation with consecutive elimination of CH(2)NR groups was observed.

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Section: Methodsmentioning

confidence: 99%

Mass spectrometric studies of benzoxazine resorcarenes

Hakala

Nuutinen

Straub

et al. 2002

Rapid Comm Mass Spectrometry

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“…It should be noted, however, that if the metal concentration in the solution is too high, ‘false positive’ complex ions may form during the solvent evaporation step of the ESI process 15. Transition‐metal complexes, other than those formed with biopolymers or synthetic polymers, have rarely been characterized by the MALDI method 16–18…”

Section: Methodsmentioning

confidence: 99%

“…The following matrices were used with the piperazine ligands: 1‐(2‐benzothiazolyl)‐3‐(4‐methoxyphenyl)‐5‐phenyl formazan (BMOF),16 2,5‐dihydroxybenzoic acid (DHB),22 1,8,9‐trihydroxyanthracene (dithranol),23 2‐(4‐hydroxyphenylazo)benzoic acid (HABA),24 9‐nitroanthracene (9‐NA),25 2,4,6‐trihydroxybenzoic acid (2THB), 3,4,5‐trihydroxybenzoic acid (3THB), and 2,4,6‐trihydroxyacetophenone (THAP) 26. The matrix and the sample were mixed in molar ratio 200:1.…”

Section: Methodsmentioning

confidence: 99%

Mass spectrometric studies on pyridine‐piperazine‐containing ligands and their complexes with transition metals formed in solution

Nuutinen

Purmonen

Ratilainen

et al. 2001

Rapid Comm Mass Spectrometry

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Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) methods were used to study open-chain piperazine-containing ligands (L) and their complexes formed with transition-metal salts. ESI and MALDI measurements were performed with a Fourier transform ion cyclotron resonance (FT-ICR) and a time-of-flight (TOF) mass spectrometer, respectively. Only singly charged complexes, between one ligand and one or several metal ions, were formed in the ESI measurements. Because the net charge was always one, one or several counterions were attached to the complex. Under ESI conditions, the complexes formed between the ligands and metal (Co, Ni, Cu, and Cd) salts were [L + M + X](+), [L + H + M + X(2)](+) and [L + M(2) + X(3)](+) (M = metal ion, X = counterion). In collision induced dissociation reactions the [L + H + M + X(2)](+) complexes easily eliminated one proton and one counterion. Fragmentation pathways were more dependent on the metal ion than the ligand, and elimination of the second counterion occurred with one proton from copper and nickel complexes and with one proton and one hydrogen from cobalt complexes. Differences in the fragmentation of the complexes could be due to electronic configuration of the metal ion. In the MALDI measurements the ratio between the [L + H](+) and [L - H](+) ions varied with the matrix. Fragmentation of the ligands through elimination of 2-methylpyridine end groups occurred with the aromatic matrices containing carboxylic acid and hydroxyl substituents. Ionization of the complexes was not successful with MALDI as the matrix molecules were also attached to the complexes.

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“…51 The data obtained suggest that formazan molecules are photoionised to molecular radical ions, which are further involved in ion-molecular reactions. Formazans give singly charged metal formazanates with the composition 1 : 2.…”

Section: Synthesis and Properties Of Formazan Derivativesmentioning

confidence: 96%