[Show abstract][Hide abstract] ABSTRACT: A new series of ruthenium(II) complexes with the general formula [RuII(aneS4)(NN)]X2, where NN are bidentate diimines, aneS4 is 1,4,7,10-tetrathiacyclododecane, and X is Cl− or PF6−, were studied by electrospray mass spectrometry (ESMS). Thiacrown fragmentation and intact diimine loss are the two major types of gas-phase reactions observed. The diimine losses occur mainly from the ion pairs formed by the inner sphere cations with halogen anions and are more significant for the complexes with flexible cross-bridged diimines. The fragmentations occur predominantly without changes in the oxidation state of the metal centre.
International Journal of Mass Spectrometry 06/2005; 243(3):257-268. DOI:10.1016/j.ijms.2005.03.008 · 1.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction Dimethyl ether, when used in chemical ionization mass spectrometry, produces the CH 3 OCH 2 + cation, m/z 45, which behaves like an ambident electrophile 1 . The reactions of various types of compounds with DME have been studied 1,2 and reviewed 3 by several authors. A number of arylalkylamines structurally related to the important group of the biogenic amines has been the subject of recent work and their proton afinitties have been determined 4,5 . The present work extends the study of these amines, of general molecular formula R 1 R 2 C 6 H 3 CHR 3 (CH 2 ) n NR 4 R 5 , to their reactions with DME. Amine n R 1 R 2 R 3 R 4 R 5<F12
[Show abstract][Hide abstract] ABSTRACT: The quantification of gaseous carbon dioxide, CO2, adsorbed by tertiary alkanolamines was performed using a quartz crystal microbalance. Carbon dioxide was injected over piezoelectric quartz crystals coated with different amounts of N,N,N,',N'-tetrakis(2-hydroxyethyl)ethylenediamine (THEED), N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine (Quadrol), and triethanolamine (TEA), and the frequency decrease of the crystals was recorded. The nature of the interaction of the alkanolamines with CO2 was investigated by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), fast atom bombardment mass spectrometry (FABMS), and mass spectrometry/mass spectrometry (MS/MS).
Canadian Journal of Chemistry 01/1999; 77(3):401-408. DOI:10.1139/cjc-77-3-401 · 1.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The unimolecular metastable decompositions of protonated arylalkylamines of general formula R1R2C6H3CHR3(CH2)(n)NR4R5 where R1 = H or OH; R2 = H, F, NO2, OH or OCH3; R3= H or OH; R4 and R5 = H and/or CH3; and n = 1-3, generated by chemical ionization with water and ammonia as ionizing reagents, have been examined via the analysis of the mass-analysed ion kinetic energy spectra of the protonated molecules. The mechanisms proposed have been probed by chemical ionization of the deuterated analogues of the amines with D2O and ND3. The results show that protonation occurs preferentially on the amino group leading to abundant ions due to ammonia (or amine) loss, although ions resulting from transfer of the proton from the amino group to the aromatic ring, to the hydroxy group para to the aliphatic chain and to the benzylic OH, are also observed. Experimental evidence for H/D exchange between the deuteronated amino group and the aromatic ring is presented, and discussed in terms of the internal energy content of the deuterated ions and structural features of the amines, such as aliphatic chain length and the presence of a second hydroxy group on the aromatic ring.
Rapid Communications in Mass Spectrometry 01/1998; 12(13):825-832. DOI:10.1002/(SICI)1097-0231(19980715)12:13<825::AID-RCM243>3.0.CO;2-K · 2.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The kinetic method was used to determine the proton affinities of phenylalkylamines of general formula R1R2C6H3CHR3(CH2)nNR4R5 where R1 = H or OH; R2 = H, F, NO2, OH or OCH3; R3 = H or OH; R4 and R5 = H and/or CH3; n = 1−3. Amines were used as reference bases and the proton affinities of the phenylalkylamines were bracketed by a pair of reference bases that give rise, in the MIKE spectra of the heterodimer, to more or less intense signals than the compound under study. The influence of the aliphatic chain length and of the substituents on the aromatic ring, on the proton affinities of the phenylalkylamines is presented and discussed. The formation of an hydrogen bond between the amino group and the aromatic ring is proposed to explain the results obtained.
International Journal of Mass Spectrometry and Ion Processes 01/1998; 172(1):123-127. DOI:10.1016/S0168-1176(97)00252-8
[Show abstract][Hide abstract] ABSTRACT: The identification of testosterone, pregnelonone, and 17α-hydroxyprogesterone by tandem mass spectrometry and of progesterone
by sequential product ion scanning in the shrimp gonads of Penaeus japonicus is described. The identification of these substances in biological samples is usually done by gas chromatography-mass spectrometry
and involves several liquid chromotographic purification steps followed by derivatization. The utilization of tandem mass
spectrometry in this analysis has simplified considerably the sample pretreatment and provided a very simple method of screening
these substances in complex mixtures.
Journal of the American Society for Mass Spectrometry 04/1997; 8(4):365-370. DOI:10.1016/S1044-0305(96)00282-6 · 2.95 Impact Factor