Equivalence of regularity for the Bergman projection and the\bar \partial-neumann operator

A necessary and sufficient condition for regularity of the -Neumann operator on (0,q)-forms in a smooth bounded pseudoconvex domain in Cⁿ is that the orthogonal projections onto -closed forms of degrees (0,q−1), (0,q), and (0,q+1) all be regular. The first author partially supported by NSF Grant DMS-8701038     

The electronic structure of benzvalene : Photoelectronspectroscopic studies

The photoelectron(PE)spectrum of tricyclo[3.1.0.0^2,6] hex-2-ene(benzvalene 1) has been recorded. The first four bands in the PE spectrum of 1 can be assigned to transitions to ²B₂, ²A₁, ²A₂ and ²B₁ states of 1¹. This assignment is discussed in terms of the results of semiempirical and ab initio calculations on 1. Furthermore the highest occupied MO's of 1 are derived qualitatively from an interaction diagram between a distorted bicyclobutane and an ethylene moiety.     

Cis di-oxomolybdenum(VI) complexes with a tridentate ONO donor ligand; synthesis,X-ray crystal structure,spectroscopic properties and oxotransfer chemistry

The molybdenum complexes of Schiff base ligands viz. [MoO₂LH₂O] where L¹ = tris(hydroxymethyl)(salicylide-neamino)methane, L² = tris(hydroxymethyl)(2,3-dihydroxybenzylideneamino)methane and L³ = tris(hydroxymethyl)(2,3,4-trihydroxybenzylideneamino)methane have been synthesized and characterized by spectroscopic and electrochemical techniques. The X-ray crystal structure of the complex [MoO₂L¹H₂O] reveals a distorted octahedral geometry with one ligand and a water molecule coordinated to the MoO₂ center. No previous complex of this type contains a coordinated water molecule. The complex undergoes an oxotransfer in the presence of Bu₃P to form a -oxobridged molybdenum(V,V) dimer. This rules out Mo—S coordination as a prerequisite for oxotransfer in such molybdenum(VI) complexes.     

Über 1,3,2-Benzoxathiaborole

On 1,3,2-Benzoxythioborols 2-Mercapto-4-methoxyphenol reacts with BCl₃ giving the 2-Chloro-5-methoxy-1,3,2-benzoxythioborol. This compound reacts with phenol, thiophenol, 2-mercapto-4-methoxyphenol, sec. amines, lithium butyl and lithium phenyl and the corresponding 2-substituted products are obtained. With sodium two borol rings are connected resulting a boron-boron bond. The Lewis-acid behaviour of some of this compounds is investigated.     

Der Stoffwechsel von Verbindungen mit Dreifachbindung. VI. Stoffwechselverhalten von Alkincarbonsäuren und Alkindicarbonsäuren

Metabolism of Acetylenic Monocarboxylic and Dicarboxylic Acids Feeding of acetylenic monoacids with chain length of 11 to 18 C-atoms to rats led to excretion of dicarboxylic acids with retained triple bonds. 10-Octadecynoic acid led to the formation of metabolites with even and odd number of C-atoms, suggesting in addition to established ω- and β-oxidation an α-oxidative pathway.     

Comparison of electrospray ionization,atmospheric pressure chemical ionization,and atmospheric pressure photoionization for the analysis of dinitropyrene and aminonitropyrene LC-MS/MS

The only relevant source for human exposure to dinitropyrenes is diesel engine emissions. Due to this specificity, dinitropyrenes may be used as biomarkers for monitoring human exposure to diesel engine emissions. Only few analytical methods have been described for the quantitation of dinitropyrenes and their metabolites, aminonitropyrenes, and diaminopyrenes. Therefore, for dinitropyrenes, aminonitropyrenes, and diaminopyrenes were selected as model compounds for the development of a sensitive HPLC-MS/MS method (high performance liquid chromatography coupled to triple quadrupole mass spectrometry) was to quantify polyaromatic amines and nitroarenes in biological matrices was developed optimal methods by comparing electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI) sources. Dinitropyrene was not effectively ionized and diaminopyrene yielded mainly [M(.)](+) ions by electrospray ionization. With APCI and APPI, precursor ions of diaminopyrene and aminonitropyrene were [M + H](+) and [M(.)](-) for dinitropyrene. Precursor ions with [M - 30(.)](-) for dinitropyrene and [M - 30 + H](+) for aminonitropyrene were observed. Reversed and normal phase HPLC-MS/MS with ESI, APCI and APPI were optimized separately with respect to unequivocal analyte identification and sensitivity. Normal phase HPLC coupled to APPI-MS/MS gave the highest precision and sensitivity for aminonitropyrene (6%/0.2 pg on column) and dinitropyrene (9%/0.5 pg on column). The limit of detection in spiked rat plasma was 5 pg/100 microL for aminonitropyrene (accuracy 82%) and 10 pg/100 microL for dinitropyrene (accuracy 105%). In plasma of rats treated with dinitropyrene by oral administration, no detectable levels of dinitropyrene but higher aminonitropyrene levels compared with intratracheal instillation were observed. These findings clearly demonstrate that dinitropyrene was absorbed after oral and intratracheal application and that a reduction of nitro groups occurs to a high extent in the reductive environment of the intestine. To our knowledge, this is the first time that aminonitropyrene was observed in plasma after intratracheal or oral administration directly demonstrating the reductive metabolism of dinitropyrene in vivo.     

Pseudohalogenverbindungen. XX. Perfluorierte alkan- und phenylsulfonylpseudohalogenide

The pseudohalide CF₃SO₂NCO has been synthesized by means of a new reaction involving trifluoromethanesulphonamide and chlorosulphonylisocyanate. This method may be used for preparing other perfluorinated alkanesulphonyl-, arenesulphonyl- and alkanecarbonyl-amides. Reactions of CF₃SO₂NCO with alcohols, thiols, phenols and amines lead to the corresponding carbonic acid esters, thio-esters, phenyl esters and ureas. Reactions with carbonic acids, aldehydes and dimethylsulphoxide gave CO₂ and the corresponding acid amides, azomethines and imino-dimethylsulphurane. Under pressure at 160°C, CF₃SO₂NCO reacts with phosphorus pentasulphide to give the previously unknown compound CF₃SO₂NCS; with phosphorus pentachloride under the same conditions, CF₃SO₂NCCl₂ is formed.