Acid dissociation constants of substituted methanediphosphonic acids. Correlation with phosphorus-31 magnetic resonance chemical shift and with Taft σ*

Grabenstetter, Robert J.; Quimby, Oscar T.; Flautt, Thomas

doi:10.1021/j100872a006

Cited by 47 publications

(17 citation statements)

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“…In a similar manner, increasing the precipitating solution's calcium/ATMP molar ratio can effectively reduce the p K a values by chelation reactions involving calcium and ATMP, resulting in an increase in the ability of the ATMP molecule to deprotonate. − This observation is illustrated in Figure . By plotting the calcium/ATMP molar ratio of the precipitate as a function of solution pH, it is evident that increasing the precipitating solution's molar ratio from 1:1 to 10:1 changes the pH value at which the transformation between distinct precipitates occurs.…”

Section: Resultsmentioning

confidence: 92%

Precipitation and Dissolution of Calcium−ATMP Precipitates for the Inhibition of Scale Formation in Porous Media

et al. 1997

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The precipitation reaction between aminotri(methylenephosphonic acid) (ATMP), a phosphonate used for scale prevention in high-water-volume industrial processes such as petroleum production, and calcium was systematically studied. By varying the precipitating conditions, three distinct precipitates formed: a crystalline, sheetlike, 1:1 calcium−ATMP precipitate; an amorphous, spherical-shaped, 2:1 calcium−ATMP precipitate; and an amorphous, spherical-shaped, 3:1 calcium−ATMP precipitate. Corresponding batch dissolution experiments showed that as the precipitate calcium−ATMP molar ratio increased from 1:1 to 2:1 to 3:1, the rate of dissolution and the equilibrium solubility limit decreased significantly. The significance of these observations was evident when the release characteristics of each precipitate from porous media were studied as related to ATMP use in oil-recovery systems. The 3:1 calcium−ATMP precipitate was released from porous media in a much slower manner than the other two precipitates, strongly suggesting that the 3:1 precipitate is most suitable for use in oil recovery.

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Section: Resultsmentioning

confidence: 92%

Precipitation and Dissolution of Calcium−ATMP Precipitates for the Inhibition of Scale Formation in Porous Media

et al. 1997

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“…Attempts have been made to explain the variations in acid dissociation constant of a series of methylene diphosphonic acids (RiR2C(P08H2)2) on the basis of the effects of the substituents Ri and R2A3 In particular, the acidity of H4EHDP was weaker than predicted on the basis of just substituent electron-withdrawing effects.3 Insofar as steric effects may also be important in this respect, a comparison of the structures of methylene diphosphonic acid (H4MDP, Ri = R2 = H) and H4EHDP (Ri = CH5, R2 = OH) is of interest On replacing the methylene hydrogens of H4MDP with the more sterically active OH and CHS groups several changes to relieve steric strain might be possible: (1) an increase in the C-P-0 angles with a concurrent decrease in the O-P-O angles; (2) a decrease in the P-C-P angle with a concurrent decrease in the P distance; (3) a rotation about the P-C bonds; and/or (4) a lengthening of the P-C bonds. The first of these effects is not observed, as average values for these angles are quite similar in both molecules.…”

Section: Discussionmentioning

confidence: 99%

Structural investigations of calcium binding molecules. I. Crystal and molecular structures of ethane-1-hydroxy-1,1-diphosphonic acid monohydrate, C(CH3)(OH)(PO3H2)2.H2O

Uchtman¹,

Gloss²

1972

J. Phys. Chem.

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“…In Equations 4 and 5, n j represents the number of each substituent of type j as defined in Table IV phosphonates determined either experimentally or found in the literature (7,8,29). As shown in Table III, (Table IV) is therefore believed to reflect the importance of the structural changes occurring at the level of the substituent due to the protonation of the molecule.…”

Section: P Nmr Behavior Of Aminophosphonates-mentioning

confidence: 99%

α- and β-Phosphorylated Amines and Pyrrolidines, a New Class of Low Toxic Highly Sensitive 31P NMR pH Indicators

Pietri¹,

Miollan²,

Martel³

et al. 2000

Journal of Biological Chemistry

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Fourteen linear and cyclic ␣-and ␤-aminophosphonates in which the P-atom is substituted by alkoxy groups have been synthesized and evaluated as 31 P NMR pH markers in Krebs-Henseleit buffer. pK a values varied with substitution in the range 1.3-9.1, giving potentially access to a wide range of pH. Temperature had a weak influence on pH and a dramatic increase in ionic strength slightly modified the pK a of the pyrrolidine diethyl(2-methylpyrrolidin-2-yl)phosphonate (DEPMPH). All compounds displayed a 4-fold better NMR sensitivity than inorganic phosphate or other commonly used phosphonates, as assessed by differences ␦ b -␦ a between the chemical shifts of the protonated and the unprotonated forms. In isolated perfused rat hearts, a non-toxic concentration window of 1.5-15 mM was determined for three representative compounds. Using empirical linear relationships, the experimental values of pK a , ␦ a , and ␦ b have been correlated with the two-dimensional structure, i.e. the chemical nature of substituents bonded to the secondary amine and P-atom. The data suggest that DEPMPH and its cyclic and linear variants are ideal versatile 31 P NMR probes for the study of tenuous pH changes in biological processes.Since the pioneering studies of Moon and Richards (1), 31 P NMR has become the standard noninvasive technique to determine the intracellular pH in a variety of biological models, based on the dependence of the endogenous inorganic phosphate (P i ) chemical shift on pH. In addition, the ex vivo or in vivo use of 31 P NMR can concomitantly give access to dynamic processes involving the cellular phosphorylated metabolites. However, the usefulness of P i as a 31 P NMR probe for the measurement of pH in biological systems is limited by its low and varying concentration during metabolism and by its sensitivity to ionic strength. Indeed, owing to the large line widths of cellular peaks, and since the mean difference ⌬␦ ab between the 31 P NMR chemical shifts of the protonated (␦ a ) and the unprotonated (␦ b ) forms of P i is only 2.6 -2.7 ppm, it cannot be used to provide information on differences on pH between intra-and extracellular compartments of less than 0.2 pH units (2).A number of endogenous and exogenous analogues of phosphates and phosphonic acid metabolites have been tested as alternatives to P i for the 31 P NMR measurement of pH but their pK a and chemical shifts were found to be influenced by ionic strength and Mg 2ϩ concentration while their NMR sensitivity ⌬␦ ab was not greatly increased with respect to that of P i (1-4). Later, it was considered that changing the chemical nature of the substituents around the protonation site of selected phosphates (i.e. the two anionic oxygens) might result in an increase in the NMR sensitivity for pH determinations. Therefore, commercially available alkyl-and aminophosphonates have been extensively studied in test solutions (3-11), cell cultures or preparations (5-9, 12), tumors (10), and isolated organs (13-16). The most commonly used charged phosphonates (e.g. me...

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Acid dissociation constants of substituted methanediphosphonic acids. Correlation with phosphorus-31 magnetic resonance chemical shift and with Taft σ*

Cited by 47 publications

References 0 publications

Precipitation and Dissolution of Calcium−ATMP Precipitates for the Inhibition of Scale Formation in Porous Media

Precipitation and Dissolution of Calcium−ATMP Precipitates for the Inhibition of Scale Formation in Porous Media

Structural investigations of calcium binding molecules. I. Crystal and molecular structures of ethane-1-hydroxy-1,1-diphosphonic acid monohydrate, C(CH3)(OH)(PO3H2)2.H2O

α- and β-Phosphorylated Amines and Pyrrolidines, a New Class of Low Toxic Highly Sensitive 31P NMR pH Indicators

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