Mass spectral studies of metal chelates. III. Mass spectra and appearance potentials of substituted acetylacetonates of trivalent chromium. Comparison with other trivalent metals of the first transition series

1969 ◽  
Vol 8 (3) ◽  
pp. 474-480 ◽  
Author(s):  
George M. Bancroft ◽  
C. Reichert ◽  
John B. Westmore ◽  
Hyman D. Gesser
Keyword(s):  
Mass Spectra ◽  
Metal Chelates ◽  
Trivalent Chromium ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Transition Series ◽  
Trivalent Metals

Mass spectral studies of metal chelates. II. Mass spectra and appearance potentials of acetylacetonates of trivalent metals of the first transition series

1968 ◽  
Vol 7 (5) ◽  
pp. 870-874 ◽  
Author(s):  
G. Michael Bancroft ◽  
C. Reichert ◽  
John B. Westmore
Keyword(s):  
Mass Spectra ◽  
Metal Chelates ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Transition Series ◽  
Trivalent Metals

Mass spectral studies of metal chelates. V. Mass spectra and appearance potentials of some fluorine-substituted acetylacetonates

1970 ◽  
Vol 48 (9) ◽  
pp. 1362-1370 ◽  
Author(s):  
C. Reichert ◽  
G. M. Bancroft ◽  
J. B. Westmore
Keyword(s):  
Mass Spectra ◽  
Molecular Ions ◽  
Metal Chelates ◽  
Spectral Studies ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Fragment Ions ◽  
D Orbitals

The mass spectra of the hexafluoroacetylacetonates (hfacac) and trifluoroacetylacetonates (tfacac) of Al(III), Cr(III), Fe(III), Fe(II), Cu(II), and Zn(II) are reported. The main features of the spectra are discussed. Compared with the spectra of the acetylacetonates (acac), substitution of CF3 for CH3 in these complexes leads to more extensive fragmentation of the molecular ions. For example, ions corresponding to loss of •CF3 radicals are more abundant than those corresponding to loss of •CH3 radicals. The appearance potentials (a.p.'s) of the molecular ions and, where possible, of fragment ions formed from the molecular ion by loss of •CF3, •CH3, or ligand radicals are reported. The a.p.'s of the molecular ions are more sensitive to the nature of the ligand than to the metal. Thus, for the metal chelates studied here the a.p.'s of the molecular ions from ML2 and ML3 (L stands for ligand) were 9.95 ± 0.25 V for L = hfacac, 9.05 ± 0.35 V for L = tfacac, and 8.3 ± 0.35 V for L = acac. The energy required to dissociate a •CF3 or •CH3 radical from the molecular ion is sensitive to the nature and valency of the metal M, being low (relatively) for Al(III) and Fe(III), and high (relatively) for Cr(III) (inferred) and Fe(II). This variation is discussed in terms of the effect of substituent, and of interaction of metal d orbitals with the ligands.

Electron ionization mass spectrometry of aryl- and fluoroalkyl-substituted palladium(II) β-diketonates and monothio-β-diketonates

1994 ◽  
Vol 72 (5) ◽  
pp. 1302-1311 ◽  
Author(s):  
Mark L. J. Reimer ◽  
John B. Westmore ◽  
Manoranjan Das
Keyword(s):  
Mass Spectra ◽  
Electron Ionization ◽  
Electron Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Aryl Group ◽  
Mass Spectral ◽  
Transition Series ◽  
Electron Ionization Mass Spectra ◽  
Positive Ion ◽  
Sulfur Donor

Positive ion electron ionization mass spectra are presented for palladium(II) β-diketonates and monothio-β-diketonates of the general form PdII[RC(X)CHC(O)R′]2, where R = phenyl, 4-methoxyphenyl, 2-thienyl, or 2-naphthyl; R′ = trifluoromethyl, pentafluoroethyl, or n-heptafluoropropyl; and X = O or S. The mass spectral behavior is in sharp contrast to that of metals of the first transition series. The spectra of the β-diketonates are dominated by metal-containing ions that arise by migration of the R group from the ligand (L) to palladium, but there is no evidence for fluorine-to-metal transfer. These findings are consistent with HSAB theory. The strong tendency of palladium to form bonds with unsaturated carbon also leads to remarkably abundant metal-containing ions that arise by losses of CO or aryloxy radicals from [PdRL]+• ions. In contrast, in decompositions of ions in the spectra of the monothio-β-diketonates, migration of the R group is suppressed; competition for palladium dπ electrons by the sulfur donor makes palladium a poorer aryl group acceptor.

Infrared, N.M.R. and mass spectral studies on 3-Amino-4-aryl-5-aryl(or alkyl)imino-4,5-dihydro-1,2,4-thiadiazoles

1975 ◽  
Vol 28 (3) ◽  
pp. 591 ◽  
Author(s):  
CP Joshua ◽  
KN Rajasekharan
Keyword(s):  
Spectral Data ◽  
Structure Elucidation ◽  
Mass Spectra ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Fragmentation Patterns ◽  
Chemical Evidence

Some 3-amino-4-aryl-5-aryl(or alkyl)imino-4,5-dihydro-1,2,4-thiadiazol, previously prepared and assigned structures on chemical evidence, are now confirmed in structure by a detailed study of their spectra. While i.r, and n.m.r, spectral data confirm the nature of the ring present in these compounds, mass spectra confirm the assignment of substituents on the ring. Mass spectra of these compounds exhibit specific fragmentation patterns and consequently are useful in structure elucidation of substituted 4,5-dihydro-1,2,4-thiadiazoles.

Synthesis of phenethanolamine derivatives with potential β-adrenergic antagonistic activity

1975 ◽  
Vol 28 (5) ◽  
pp. 1023 ◽  
Author(s):  
SJ Pasaribu ◽  
LR Williams
Keyword(s):  
Magnetic Resonance ◽  
Ring Opening ◽  
Proton Magnetic Resonance ◽  
Mass Spectra ◽  
Antagonistic Activity ◽  
Spectral Studies ◽  
Aryl Ring ◽  
Mass Spectral

The mass spectra of bromonitroacetophenones, intermediates in the synthesis of phenethanolamine derivatives containing a nitro and bromo group in the aryl ring, have been studied. The acetophenones were converted into the corresponding α,β-epoxystyrenes, which were then treated with various amines, and proton magnetic resonance and mass spectral studies were used to confirm the direction of ring opening and purity of the products.

scholarly journals Mass Spectral Studies on Some Naturally Occurring Phloroglucinol Derivatives. III. The Mass Spectra of Some Mono- and Bicyclic Phloroglucinol Derivatives from Rhizomes of Different Dryopteris Species.

1972 ◽  
Vol 26 ◽  
pp. 89-101 ◽  
Author(s):  
Mauri Lounasmaa ◽  
Arto Karjalainen ◽  
Carl-Johan Widén ◽  
Aarre Huhtikangas ◽  
W. B. Pearson ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Naturally Occurring ◽  
Phloroglucinol Derivatives

scholarly journals Mass Spectral Studies on Some Naturally Occurring Phloroglucinol Derivatives. Part I. The Mass Spectra of Filicinic Acid and its Acetyl, Propionyl, and Butyryl Derivatives.

1971 ◽  
Vol 25 ◽  
pp. 3428-3440 ◽  
Author(s):  
Mauri Lounasmaa ◽  
Arto Karjalainen ◽  
Carl-Johan Widén ◽  
Aarre Huhtikangas ◽  
J. Koskikallio ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Naturally Occurring ◽  
Phloroglucinol Derivatives

Mass spectral studies of aromatic aza analogues of juvabione

1986 ◽  
Vol 51 (12) ◽  
pp. 2879-2883
Author(s):  
R. K. Mahajan ◽  
Neelam Gupta ◽  
Satinder K. Uppal
Keyword(s):  
Mass Spectra ◽  
Spectral Studies ◽  
Fragmentation Pattern ◽  
Mass Spectral ◽  
Secondary Amides

Mass spectra of title compounds I-VI have been studied with a view to comparing the fragmentation pattern of secondary amides in different structural environments.

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