Organophosphorus bidentate

Bidentate phosphate compounds. The organophosphorus bidentate extractants are neutral species extractants that undergo no keto-enolization and have no exchangeable hydrogens (as is the case in extraction by the bidentate diketones). They contain either two P=0 groups or one P=0 and one C=0 group. The carbamoylmethyl-phosphonates (CMPs) and carbamoylphosphonates (CPs) are examples of the latter, while the tetraalkyldiphosphonates and tetraalkyl-diphosphinedioxides [or bis-(disubstituted phosphinyl)-alkanes] are examples of the former. 

Work with the organophosphorus bidentate vinylene diphosphine, in which the phosphoryls are bridged lP(0)CH = HC(0)Pv, illustrates the importance of steric considerations in the extraction of uranyl... 

The organophosphorus bidentate octaethyltetraamidopyro-phosphate (OETAPP), a compound of the type R.2P(0)NH(0)PR.2, is noted for the extraction of uranium from HC1 as well as HNO3. 

Indeed, these reactions proceed at 25 °C in ethanol-aqueous media in the absence of transition metal catalysts. The ease with which P-H bonds in primary phosphines can be converted to P-C bonds, as shown in Schemes 9 and 10, demonstrates the importance of primary phosphines in the design and development of novel organophosphorus compounds. In particular, functionalized hydroxymethyl phosphines have become ubiquitous in the development of water-soluble transition metal/organometallic compounds for potential applications in biphasic aqueous-organic catalysis and also in transition metal based pharmaceutical development [53-62]. Extensive investigations on the coordination chemistry of hydroxymethyl phosphines have demonstrated unique stereospe-cific and kinetic propensity of this class of water-soluble phosphines [53-62]. Representative examples outlined in Fig. 4, depict bidentate and multidentate coordination modes and the unique kinetic propensity to stabilize various oxidation states of metal centers, such as Re( V), Rh(III), Pt(II) and Au(I), in aqueous media [53 - 62]. Therefore, the importance of functionalized primary phosphines in the development of multidentate water-soluble phosphines cannot be overemphasized. 

Siddall, Jr. T.H. Bidentate organophosphorus compounds as extractants-II. Extraction mechanisms for cerium(IH) nitrate, J. Inorg. Nucl. Chern. 26 (1964) 1991-2003. 

Diphcnyl-/V,/V-di obutylcarbamoylmcthylphosphinc oxide (Ph2-CMPO, Figure 3.3), a bidentate neutral organophosphorus compound (BNOPC) derived from the TRUEX process, which proved to be efficient for the removal of actinides and REEs. 

FIGURE 3.6 Bidentate neutral organophosphorus compounds (BNOPCs) diphosphine dioxides. 

Smirnov I.V. Anomalous effects in extraction of lanthanides and actinides with bidentate neutral organophosphorus extractants. Role of proton hydrate solvates. Radiochemistry (2007), 49 (1), 44-54. 

Coordination compounds of diphosphazane dioxides with uranyl or thorium ions were synthesized [475], The crystal structure of [U02(N03)2L1] [L, = Ph2P(0) N(Ph)P(0)Ph2] reveal the bidentate chelating mode of binding of the diphosphazane dioxide to these metals. The chemistry of other uranium organophosphorus and related compounds is described [476-479]. Some of the actinide complexes are presented in Table 5.16. 

Mclsaac, L. D. and Schulz, W. W. Removal of Actinides from Nuclear Fuel Reprocessing Waste Solution with Bidentate Organophosphorus Extractants in "Transplutonium 1975,"... 

It is well-known that certain bidentate neutral organophosphorus compounds are far better extractants than their monodentate analogues (1, ). 

Bidentate neutral organophosphorus compounds were synthesized in the laboratory of organophosphorus compounds, USSR Academy of Sciences as described in ( -11), the tri- and tetradentate compounds as described in (11). The reagents were dissolved in chloroform or cTTchloroethane. 

Since TBP leaves Am(iii) behind in an addic raffinate, an effective extractant is needed to remove Am(iii) from such media. Siddall found that bidentate extractants have this desirable property [44]. Schulz [45] and Mclsaac [46] at the Hanford and Idaho Falls sites, respectively, have recently revived interest in plant-scale application of neutral bidentate organophosphorus extractants, particularly dihexyl-iV,iV-diethylcarbamoyl methylenephosphonate (DHDECMP) and dibutyl-iV,iV-diethylcarbamoyl methylenephosphonate (DBDECMP). The binding of actinide ions to DHDECMP has not been eluddated fully. Horwitz [335] states that in perchloric add the extractant is... 

Turanov, A.N. Karndashev, V.K Baulin, V.E. (2008). Effect of Ionic Liquids on the Extraction of Rare-earth Elements by Bidentate Neutral Organophosphorus Compounds from Chloride Solutions. Russ.. Inorg. Chem., Vol.53, pp. 970-975... 

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