ORGANOPHOSPHORUS COMPOUNDS,XXVIII. THE REACTION OF TRIPHENYLPHOSPHINE SULFIDE WITH TETRACHLOROBENZOQUINONES

Abstract

The reaction of triphenylphosphine sulfide with tetrachloro-o-benzoquinone gives a complex of the corresponding hydroquinone and triphenylphosphine oxide. Elemental sulfur is the other product. The tetrachloro-p benzoquinone does not react to any noticeable extent under similar conditions. Several mechanisms are proposed to explain the results.     

PHOSPHONIUM YLIDS-VII. SYNTHESIS OF A NEW TYPE OF YLID PHOSPHORANE BY THE ACTION OF WITTIG REAGENTS ON (E)-2-BENZYLIDENEOXAZOLIDINE-4,5-DIONE

Abstract

The reaction of (E)-2-benzylideneoxazolidine-4,5-dione (1) with the methylenetriphenylphosphoranes (2) afforded new ylid-phosphoranes of type 3. The mechanism that accounts for formation of adducts 3 is discussed. Structural reasoning for compounds 3 was based on compatible analytical, chemical and spectroscopic results.     

Organophosphorus compounds–XVIII : The reaction of alkyl phosphites with 4-triphenylmethyl-1,2-benzoquinone

Dialkyl phosphites react with 4-triphenylmethyl-1,2-benzoquinone (6) to give dihydroxyphosphonates having structure (7). Trialkyl phosphites, on the other hand, attack the carbonyl oxygen of 6, yielding cyclic unsaturated pentaoxyphosphoranes (17). These are converted into the o-quinol phosphate esters (16) by hydrogen chloride.Possible reaction mechanisms are considered and the structural assignments are based on chemical and spectroscopic evidence.     

Electrons ejected with half the projectile velocity and the saddle point mechanism in ion-atom collisions

Full three-dimensional ejected electron momentum distributions for proton impact ionization of atomic hydrogen are calculated for impact energies 10 through 50 keV. The distributions show a peak in the longitudinal momentum at half the projectile impact velocity: the v/2 peak. A quantitative assessment of saddle point ionization, based on quantum and classical analysis, reveals that the v/2 peak is a false indicator for this mechanism. The influence of the potential saddle on ionization is seen to decrease rapidly from 10 to 50 keV.     

Boundary-free propagation with the time-dependent Schrodinger equation

We present two methods that allow for the efficient numerical propagation of continuum wave packets to large times. Time-dependent solutions of the Schrodinger equation that include continuum components are numerically challenging to solve because the wave packet travels, spreads, and acquires a spatial phase gradient. The methods we propose account for these kinematic effects analytically in general and numerically tractable schemes.     

ORGANOPHOSPHORUS COMPOUNDS,XXX

Abstract

Fluoroenylidenetriphenylphosphorane (1a) reacts with maleic and phthalic anhydrides to give lactones 2a and 3, respectively. The same reagent (1a) extrudes sulphur from thiophthalic anhydride yielding the spiro-1,3-indandione derivative 4. The infrared and mass spectra of the new products are discussed.