Subject phosphorus anions

A. Analysis of Wastewater and Natural Waters. The presence of certain anions in wastewater effluents can cause deterioration of natural water systems. Phosphorous and nitrogen can be present in several chemical forms in wastewaters. Phosphorous is usually present as phosphate, polyphosphate and organically-bound phosphorus. The nitrogen compounds of interest in wastewater characterization are ammonia, nitrite, nitrate and organic nitrogen. Analyses are often based on titrimetric, and colorimetric methods (3). These methods are time consuming and subject to a number of interferences. Ion Chromatography can be used to determine low ppm concentrations of these ions in less than thirty minutes with no sample preparation. 

The synthetic utility of a-phosphorus- and a-thio-stabilized carbanions is the subject of numerous reviews.21 Notable are additions of phosphonium ylides (237),183 sulfonium ylides (238),l84 ° oxosulfo-nium ylides (239)184 " and sulfoximine ylides (240)184,1 to electron-deficient alkenes which afford nucleophilic cyclopropanation products. In contrast, with a-(phenylthio)-stabilized carbanions, which are not acyl anion equivalents, either nucleophilic cyclopropanation or retention of the hetero substituent occurs, depending on the acceptor and reaction conditions used. For example, carbanion (241) adds to 1,1-... 

One of the subjects of our investigations involved the interaction of allenes with the P=E derivatives. This work provided some very interesting, unexpected results that may well be of use in synthetic organophosphorus chemistry. Thus, in attempting to study the (2+2)-cycloadditions of the phosphinimine and the (methylene)phosphine systems with the allenic C=C bond, we established that the reactions take a different and more interesting course — that of an ene" reaction (eq 1). In the first step of the reaction, the electrophilic phosphorus center apparently attacks the nucleophilic central carbon of the allene system. Then, instead of undergoing nucleophilic attack on the incipient carbonium ion, the anionic center (E) abstracts a proton from the terminal C-H bond, leading to the formation of a new double bond in the phosphorus-substituted 1,3-butadiene derivatives (3). 

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