Umberto Vettori

University of Padua

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Pietro Traldi

Città della Speranza Foundation

Cristina Paradisi

University of Padua

Guido Banditelli

University of Milan

Anna Laura Bandini

University of Milan

R. Ettorre

University of Padua

Giovanni Minghetti

University of Sassari

Marino Basato

University of Padua

Giovanni Valle

University of Padua

Antonio Selva

Manonmaniam Sundaranar University

Gianni Podda

University of Cagliari

Cooperative Institutions

University of Padua

University of Milan

Istituto di Chimica Biomolecolare

National Interuniversity Consortium of Materials Science and Technology

Istituto di Farmacologia Traslazionale

University of Ferrara

Institute of Chemistry of Molecular Recognition

Politecnico di Milano

Institute for the Dynamics of Environmental Processes

University of Sassari

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Crystal structure and mass spectrometry of dichlorodimethylbis[2(1H)-pyridinethione-S]tin(IV)

Journal of the Chemical Society. Dalton transactions (1987)

Giovanni Valle R. Ettorre Umberto Vettori Valerio Peruzzo Gualtiero Plazzogna

The structure of the complex Sn(CH3)2Cl2·2C5H5NS has been determined by single-crystal X-ray diffraction methods. The compound crystallizes in the monoclinic system, space group P21/n, with unit-cell dimensions a= 16.793(5), b= 6.201(3), c= 7.882(3)Å, β= 90.4(3)°, and Z= 2. The configuration about the tin atom is all-trans octahedral. The C5H5NS ligands are bonded to the metal through the S atom. The observed C(2)–S bond length [1.730(g)Å] is consistent with ca. 35% double-bond character, compared to ca. 55% for the uncomplexed ligand. The H atoms on the N atoms are involved in intramolecular hydrogen bonding with the chloride ligands, N–H ⋯ Cl 3.199(9)Å. Mass spectra of Sn(CH3)2Cl2·2C5H5NS show that facile elimination of HCl from the complex occurs to give a series of ions containing the ligand C5H4NS; these can be formulated as complexes of the 2-pyridinethiolate anion, probably bonded through the S atom. Mass spectra of the metastable ion [Sn(CH3)Cl(C5H4NS)]+ show that the Sn–L bond strengths are in the order L = methyl < chlorine < 2-pyridinethiolate.

Monoclinic crystal system

10.1039/dt9870000815

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Citations (34)

Instrumental parameterization for optimum use of commercial direct inlet systems

Organic Mass Spectrometry (1982)

Pietro Traldi Umberto Vettori Franco Dragoni

Abstract Commercial direct insertion probes generally do not operate under ideal conditions required for direct inlet systems, with the consequence of large decomposition effects for thermolabile compounds. Instrumental parameters for two different probes are given which indicate that under the best conditions a molecular distillation occurs with drastic reduction of pyrolysis processes.

Thermolabile

10.1002/oms.1210171112

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Citations (46)

ITMS capabilities in isomer analysis. Part 3. Characterisation of methyl and dimethyl derivatives of 8-desmethylseseline, potential anti-proliferative agents, by tandem mass spectrometry

International Journal of Mass Spectrometry and Ion Processes (1991)

Bernard T. Kiremire Pietro Traldi A. Guiotto G. Pastorini Adriana Chilin

Chromone

Collision-induced dissociation

Tandem

10.1016/0168-1176(91)85024-g

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Citations (11)

A study of relevant parameters in collisional‐activation of ions in the ion‐trap mass spectrometer

Rapid Communications in Mass Spectrometry (1990)

Janina Gronowska Christina Paradisi Pietro Traldi Umberto Vettori

Abstract Variously substituted aryl ketones served as models to gain insight into the collisional‐activation process in an ion‐trap mass spectrometer. The effects of different targets (helium, argon) at different pressures were examined. The investigation also involved the comparison of the results of tandem mass spectrometry experiments in the ion trap with those obtained in high‐energy collision and mass‐analysed ion kinetic energy experiments in a sector instrument. Use of argon and low helium pressures in the ion trap results in both an increase of the average internal energy of the activated ion and, presumably, a less broad energy deposition profile. The results indicate that the maximum value of internal energy achieved by an ion through multiple collisions in the ion‐trap mass spectrometer is limited by the presence of low‐energy reaction channels.

Hybrid mass spectrometer

Quadrupole ion trap

10.1002/rcm.1290040903

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Citations (78)

ChemInform Abstract: Reactions of Carbon Suboxide with Organo-Aluminum Compounds.

ChemInform (1989)

Luciano Pandolfo Gastone Paiaro Umberto Vettori

Abstract When the (II)/(I) ratio is < 2, only a R 3 Al···O=C=C=C=O complex is formed which with MeOH gives dimethyl malonate.

Suboxide

Carbon fibers

10.1002/chin.198925096

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Citations (0)

Mass Spectra and Gas‐Phase Ion Chemistry of Halogen‐Containing Compounds

Cristina Paradisi Umberto Vettori

Electrophilic aromatic substitution

Substitution reaction

Radical-nucleophilic aromatic substitution

SN2 reaction

10.1002/047002349x.ch5

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Citations (6)

Comparison of collisional activation by the ‘boundary effect’ vs. ‘tickle’ excitation in an ion trap mass spectrometer

Organic Mass Spectrometry (1992)

Cristina Paradisi John F. J. Todd Umberto Vettori

Abstract It has been shown previously that collisional activation in an ion trap mass spectrometer can be achieved by storing parent ions within a narrow zone extending close to the theoretical boundaries β r = 0 or β z = 0 of the stability diagram. This procedure can be used for obtaining collision‐induced dissociation of selected parent ions without the need to apply a precisely tuned resonant ‘tickle’ potential between the end‐cap electrodes. In this investigation a comparison was made between the two methods (‘tickle’ and ‘boundary’) of activation based on the efficiency of parent‐to‐daughter conversion and on the relative abundance of daughter ions for a model system (the m / z 91/92 ratio for n ‐butylbenzene). The data show that, under conditions of maximum efficiency, a comparable amount of internal energy is present in the ions after activation with the two methods. However, with the ‘tickle’ technique it is possible to increase the internal energy of the parent ions even further, although at the expense of the efficiency, whereas in the case of the “boundary” activation, the conditions for optimum efficiency almost coincide with those for maximum activation and a drastic loss of ions follows any attempt to overcome these limits. It is also found that at any given q z value used for storing and activating parent ions the permitted mass difference between parent and fragment ions is greater with ‘boundary’ than with ‘tickle’ excitation.

10.1002/oms.1210271110

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Citations (25)

ジメチル(トリメチルシリル)アミンと二酸化三炭素との反応 ‐Si(CH3)3基によるO‐攻撃

Gazzetta chimica italiana (1987)

Luciano Pandolfo Gastone Paiaro Umberto Vettori

Source

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Citations (2)

Electron impact mass spectrometry of 4, 5‐dihydro‐1,2,4‐benzothiadiazepine‐1,1‐dioxide derivatives

Organic Mass Spectrometry (1984)

Umberto Vettori Giordano Lesma Micaela Nali Giovanni Palmisano

Abstract The fragmentation pathways of some 4,5‐dihydro‐1,2,4‐benzothiadiazepine‐1,1‐dioxide derivatives are discussed on the basis of metastable transition data, exact mass measurements and labelling experiments. These compounds show several primary fragmentation processes: M  SO 2 , M  OH and one involving an intramolecular oxygen migration (M  CH 3 NO).

Fragmentation

Metastability

Mass

10.1002/oms.1210190604

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Citations (3)

The mass spectrometric behaviour of some iridium(I) and iridium(III) pyrazolate derivatives

Inorganica Chimica Acta (1988)

Anna Laura Bandini Guido Banditelli Giovanni Minghetti Umberto Vettori Pietro Traldi

10.1016/s0020-1693(00)80666-0

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Citations (4)