Hypophosphites Structure

Electron Diffraction. - Three gas-phase molecular structures have been determined by electron diffraction. They are the hypophosphite (80)224 trif1uorophosphine sulphide,225 and dichlorotrifluorophosphorane.224... 

Addition across the P—P and P—C bonds. Tetraethyl hypophosphite was successfuly added to la. Upon subsequent air oxidation the diphosphonate 35, and a significant amount of the more complex structure 36 were isolated48,104 (equation 18). 

The detection, estimation and structure of hypophosphites are discussed under Phosphites (q.v.). 

Structure of the Hypophosphites and Phosphites.—The monobasicity of hypophosphorous acid points to the unsymmetrical formula. The probable existence also of a proportion in the symmetrical form may be indicated by the ease with which the acid undergoes self-oxidation and -reduction on heating, thus... 

Hypophosphorous Acid—Phosphorous Acid—Hypophosphites and Phosphites, Structure and Tautomerism—Meta- and Pyro-phosphorous Acids—Detection and Estimation of Phosphites and Hypophosphites—Hypophosphoric Acid—Detection and Estimation of Hypophosphates. 

A suspension of [RuCl2(PPh3)3] in boiling MeOH containing the sodium salt of a carboxylic acid is reduced by H2 or sodium hypophosphite to give the yellow [RuH(OCOR)(PPh3)3] (R = Me, CH2C1, CFj, Et, Pr, Pr1, Ph etc.),]4S>-2461 shown by X-ray analysis (R = Me)2462 to have the distorted octahedral structure (375) which is retained in solution.2463 A more rapid preparation of these active... 

The structure of the cellulose hypophosphites synthesized has been confirmed by spectroscopy 69). The spectra erf cellulose hypophosphites show bands in the regions 2380-2440cm and l )0-1250cm" , assignable to the valence vibrations (rf the P—H and P-O groups, respectively. 

A few uranyl metaphosphates have been reported. U02(P03)2 is formed in 85% H3PO4 at 300-350 °C or by thermal decomposition of U02(H2P04)2 at 800-850 °C. In addition, there are uranyl phosphites, U02HP03-xH20, x = 0,3, and hypophosphites U02(H2P02)2 vH20. A new phosphite with a three-dimensional structure was recently prepared using hydrothermal methods. ... 

Sodium hypophosphite, NaHiPOi, has been suggested as a replacement of sodium nitrite, NaNO , as a meat preservative to prevent botulism. Draw the structure of each anion. 

The strict specificity of PFL for pyruvate and formate as substrates places some restrictions on the structure of potential active site-directed inhibitors. Therefore, acetyl phosphinate (207) is a natural candidate for a PFL inhibitor, as it is not only a pyruvate analog, but is also a derivative of hypophosphite, a known mechanism-based PFL inactivator. In the absence of CoA, 100 mM acetyl phosphinate is an effective time-dependent inhibitor of PFL, although the inactivation reaction does not appear to be first order. If 55 mM CoA is included in the inactivation reaction mixture, first-order kinetics are now observed, and with 10 mM acetyl phosphinate the half-life of the inactivation reaction is 3 min. In the presence of 5 mM pyruvate (no CoA), PFL is completely protected from inactivation by 100 mM acetyl phosphinate. 

With sodium selenide the hexaiodide (281) forms the noradamantane (284). The structure of (284) was also confirmed by x-ray <80ZN(B)i 5i4,84CB2675, 84ZN(B)1344>. The reduction of (282) with alkaline hypophosphite leads to the noradamantane (285) <84CB2675>. The noradamantanes (284) and (286) result from melting the 4-methyl-1,2,6-triarsatricyclo[2.2.1.0 ]heptane (287) with elemental sulfur or selenium (Scheme 47) <84CB2675>. 

Tetragonal crystals (rutile structure). Insol in water, nitric or cold sulfuric acid slowly dissolves in cold HC1 with evolution of Clji in presence of hydrogen peroxide or oxalic acid it dissolves in dil HjS04 or HNOj. Caution Manganese dioxide is a strong oxidizer, hence it should not be heated or rubbed with organic matter or other oxidizable substances, e.g., sulfur, sulfides, phosphides, hypophosphites, etc. LD i.v. in rabbits 45 mg/kg, Handbook of Toxicology, Vol. 1, W. S. Spector, Ed. (Saunders, Philadelphia, 1956) pp 182-183. 

An important feature of the utility of bis(trimethylsilyl) hypophosphite in synthesis consists in its capability to undergo addition reactions, and which has been exploited in several ways to provide phosphinic acids which possess carboxy groups these reactions are summarized in Scheme 40 (the structures indicated here represent the final products following the acidolytic removal of trimethylsilyl groups). An equimolar mixture of phenylphosphonous dichloride (PhPCl2) and phenylphosphonous acid (phenylphosphinic acid) behaves as the phosphinic chloride 434, and so adds across carbonyl activated carbon-carbon multiple bonds by virtue of the presence of the P—H bond propenoyl chloride thus affords the acid dichloride 435, which may be hydrolysed to 3-(hydroxyphenylphos-phinoyl)propanoic acid (436). ... 

Many thorium hypophosphites, phosphites, their hydrates and related compounds with monovalent cations (usually K ) have been mentioned in the literature (see the Gmelin review by Bickel [1993BIC]), but the information available is essentially limited to preparation procedures, analysis, vibrational spectra and some DTA studies. X-ray structures have not been reported and, in fact, many of these compounds are amorphous to X-rays. Since no thermodynamic data relevant to this review have been reported, these compounds are not considered further. 

H2O have been isolated as single crystals and their heats of formation and stabilities discussed. The structure of C02P2O7 has been reported. It has been shown that the first stage in the reduction of Co" by hypophosphite ions is the formation of a 1 1 complex. Salts of MCo"Wi (M = P,... 

Bonds to Oxygen.—Compounds of Lower Oxidation State. The chemistry of hypophosphorous acid and the metal hypophosphites has been reviewed. Improved dimensions for the HPOaOH" ion have been reported in a neutron-diffraction investigation of the structure of LiH2P03 in particular, the P— distance has been revised to 1.396 A and the presence of strong hydrogen bonds defined. 

FIGURE 5.34 Crystal structure of ammonium hypophosphite (NH4H2PO2). Small open circles = H filled circles = P. (Adapted from W.H. Zachariasen and R.C.L. Mooney, J. Chem. Phys., 2, 34,1934.)... 

Hypophosphite complexes with the empirical formula MZr(H2P02)3, where M = Mg, Cu, Fe, Ni, Zn, probably have octahedral structures (5.230), not unlike those of the triphosphitochromate anion (5.220). 

Tanner PA, Mak CSK, Mak TCW (2000) Synthesis, structure and spectroscopy of rare earth hypophosphites 3. Ytterbium hypophosphite. Polyhedron 19 863-870... 

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