Dimethylphosphate anion

Rigid-geometry ab initio MO calculations of 86 torsional isomers of the dimethylphosphate anion (CH30)2P02 led to the determination of parameters for the Lennard-Jones type of nonbonded interaction, two- and three-fold torsional, and electrostatic interaction potential functions (215). Extension of this approach to full relaxation ab initio and MM schemes will be extremely useful, not only for phosphorus but also for other heteroatoms. 

The dimethylphosphate anion has been used as model compound. The geometry and the numbering adopted are recalled in Figure 1. For easy recognition, the anionic oxygens carry the odd and the ester oxygens the even numbers. 

The data indicate that the lowest power factor (100 x tan 6) and dielectric constant (e ) values, as measured at 150 C, are shown by the samples containing MTOP-DMP and MTBP-DMP. There would appear to be a trend in these electrical data in that the samples containing halide anionic species (e.g., chloride and iodide) apparently exhibit higher power factor and dielectric constant values than the non-halide phosphonium additives. This is not too surprising because of the more polar nature of the halide ions compared to anions such as dimethylphosphate. 

OH to produce the coordinated dimethylphosphate (DMP) anion and methanol in this case, however, the reaction is accompanied by considerable Rh-O bond cleavage. This reaction presumably occurs by the characteristic dissociative conjugate base, SNl(cb), mechanism (136) for metal-ligand bond rupture, which also has a first-order dependence on hydroxide ion concentration. At zero buffer concentration the rate follows the rate law ... 

Aluminium is considered to be a very suitable material for the cathodic current collector in lithium-ion batteries, but it may corrode in contact with the electrolytes used in that kind of devices. The use of ionic liquids as corrosion inhibitors of aluminium and aluminium alloys was pointed out by Uerdingen et al. [6] when an Al- alloy (AlMg3) showed a very low corrosion rate (0.03 mm-year ) in the presence of different imidazolium derivatives with different and varying anions (ethylsulphate, octylsulphate, tosylate and dimethylphosphate), especially in the absence of water. Adding 10 % of water, mass loss values were under 0.1 mm-year. ... 

Finally, the IC-MS method that Mohsin [146] developed for the analysis of organophosphorous and organosulfur compounds in an insecticide such as monomethylphosphate, monomethylsulfate, and dimethylphosphate should be reviewed. All three compounds were separated on an lonPac ASH anion exchanger using a NaOH/methanol mixture as an eluant. Mohsin desalted the eluant with an Alltech lOOOHP suppressor, which contains two packed bed suppressor columns. One of the suppressor columns is used for suppression, while the other one is electrochemically regenerated at the same time. The suppressor effluent is split 99 1 and mixed with acetonitrile/water (90 10 v/v) containing 0.5 % ammonium hydroxide. Detection is carried out in the negative-ion mode. 

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