Volume changes in the proton ionization of amines in water. 1. Morpholines and piperazines

Cabani, Sergio; Mollica, Vincenzo; Lepori, Luciano; Lobo, Sheila Teresa

doi:10.1021/j100525a012

Cited by 22 publications

(9 citation statements)

References 12 publications

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“…The protonation constants of py-2,3-dc and pipz were calculated by fitting the potentiometric pH data to the BEST program [21] whose results are summarized in Table 5. It is noteworthy that the resulting logȕ values are in satisfactory agreement with those reported for py-2,3-dc [22], and pipz [23] in the literature. The determination of the equilibrium constants for the interactions between py-2,3-dc and pipz was accomplished through the comparison of the calculated and experimental pH profiles obtained with both py-2,3-dc and pipz present in a 1:1 ratio, as described before [15,24,25].…”

Section: Potentiometric Equilibrium Studies In Aqueous Solutionsupporting

confidence: 89%

Synthesis and crystal structure of Mn(II) and Hg(II) compounds and solution studies of Mn(II), Zn(II), Cd(II) and Hg(II) compounds based on piperazinediium pyridine-2,3-dicarboxylate

Aghabozorg¹,

Daneshvar

Motyeian

et al. 2009

JICS

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Novel metal organic frameworks including {(pipzH 2 )[Mn(py-2,3-dc) 2 ]·7.75H 2 O} n , 1, {(pipzH 2 )[Zn(py-2,3-dc) 2 ]·4H 2 O} n , 2, [Cd(py-2,3-dc)(H 2 O) 3 ] n , 3 and {(pipzH 2 )[Hg 4 Cl 10 ]} n , 4, in which pipz is piperazine and py-2,3-dcH 2 is pyridine-2,3-dicarboxylic acid were synthesized applying a proton transfer ion pair i.e. (pipzH 2 )(py-2,3-dcH) 2 and corresponding metallic salts and studied by IR, 1 H NMR, 13 C NMR spectroscopy and single crystal X-ray diffractometry. The space group of compounds 1 and 4 are P2 1 /c and C2/c of monoclinic system, respectively. The crystal dimensions are a = 20.108(2) Å, b = 19.910(2) Å, c = 12.997(1) Å, ȕ = 94.354(2)Û for 1 and a = 15.940(1) Å, b = 11.2690(9) Å, c = 11.1307(9) Å, ȕ = 90.685(2)Û for 4. The crystal structures of 2 and 3 have been reported previously. However, their solution studies are discussed here. The compounds had all polymeric structures. Although Zn II , Cd II and Hg II were elements of the same group, their behavior against the ion pair was essentially different. Various supramolecular interactions mainly hydrogen bonds of the type O-H···O, N-H···O, C-H···O, N-H···Cl and C-H···Cl were observed in the structures. There was an unusual and huge water cluster in the structure of compound 1. The solution states of compounds 1-4 were studied and reported. The protonation constants of pipz and py-2,3-dc, the py-2,3-dc/pipz proton transfer equilibrium constants and stoichiometry and stability of the system with Mn 2+ , Zn 2+ , Cd 2+ and Hg 2+ ions in aqueous solution were investigated by potentiometric pH titrations.

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Section: Potentiometric Equilibrium Studies In Aqueous Solutionsupporting

confidence: 89%

Synthesis and crystal structure of Mn(II) and Hg(II) compounds and solution studies of Mn(II), Zn(II), Cd(II) and Hg(II) compounds based on piperazinediium pyridine-2,3-dicarboxylate

Aghabozorg¹,

Daneshvar

Motyeian

et al. 2009

JICS

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“…Apparent molar volume data for these compounds in water were checked for possible changes arising from proton ionisation and disproportionation reactions, etc. (10,14,15). The corrections in +, due to such reactions were found to be within experimental error and are thus ignored.…”

Section: Resultsmentioning

confidence: 99%

Partial molar volumes of some drugs in water and ethanol at 35 °C

Iqbal¹,

Jamal²,

Ahmed³

et al. 1994

Can. J. Chem.

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Partial molar volumes, vO, of six drugs, mostly anaesthetics, viz., cinchocaine HCl, lidocaine HC1, mepivacaine HC1, procaine HC1, propranolol HC1, tetracaine HCI, in water and ethanol, calculated from precision densities obtained at 35OC from a vibrating tube densitometer, are reported in this work. The data represent the smaller volumes of drug molecules in ethanol than in water. Volume contribution of hydrochloride part were calculated and excluded from V O to assess the volume of free base component of the solutes. Volumes of free bases were also found smaller in ethanol, although much closer to those in water. The differences in volumes are interpreted as due to hydrophobicity of solutes. Relative hydrophobicities were estimated from volumes of transfer from aqueous to organic media. Correlation of V O with van der Waal volumes are also reported. The hydrophobicity of these compounds is proposed to play a key role in the resulting drug action. Possible mechanism of drug binding with the membrane structure is also discussed.

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“…the supplementary material.2 +k data for the hydrochloride salts and phenol were analyzed for possible changes arising from the proton ionisation reaction (33,34). The correction to c$k due to this reaction was found to be within the experimental error.…”

Section: Apparent Molar Volumementioning

confidence: 98%

“…[I]. Experimental $, data for all the systems studied are found in the supplementary material.2 Apparent molar volume data for the hydrochloride salts and phenol were checked for possible changes arising from the proton ionisation reaction (33,34).…”

Section: Apparent Molar Volumementioning

confidence: 99%

Apparent molar volume and adiabatic compressibility studies of aqueous solutions of some drug compounds at 25 °C

Iqbal¹,

Verrall²

1989

Can. J. Chem.

103

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MOHAMMAD IQBAL and R. E. VERRALL. Can. J. Chem. 67, 727 (1989). Apparent molar adiabatic compressibilities and volumes of aqueous solutions of the following drugs (sodium salicylate, methyl orange, L-tryptophan, phenol, and the hydrochloride salts of propranalol, procaine, pilocarpene, and ephedrine) have been calculated from high precision density and sound velocity measurements at 25°C. These drugs are considered important in several biochemical phenomena such as anomalous protein binding, anesthesia, or unique structure-activity relationship and this study is part of a comprehensive investigation of drug-protein interactions in biological systems. The data are qualitatively interpreted in terms of solute-solvent and solute-solute interactions. Some plausible modes of drug hydration are discussed with particular reference to the structure of the drug molecules. The adiabatic compressibility shows a strong correlation with the hydrational behaviour of the solute molecule and appears to be sensitive to the structural features of the solute, such as shape, size, branching, and presence of aromatic rings. It is argued that these aspects are important in terms of considering the geometrical fit of the solute into the ordered form of the aqueous solvent surrounding these solutes.Key words: apparent molar adiabatic compressibilities, apparent molar volumes, hydration of drugs.MOHAMMAD IQBAL et R. E. VERRALL. Can. J. Chem. 67, 727 (1989). Utilisant des mesures de haute prtcision de la densitt ainsi que de la vitesse du son, a 25"C, on a calculC les volumes et les compressibilitCs molaires apparentes de solutions aqueuses des drogues suivantes: salicylate de mCthyle, orange de mtthyle, L-tryptophane, phCnol ainsi que les chlorhydrates de la propanolamine, de la procaine, du piloc&ne et de 1'CphCdrine. Ces drogues sont souvent considCrtes comme importantes dans plusieurs phenomknes biochimiques tels que la liaison anormale des protkines, I'anesthCsie ou une relation structure-activitC particulikre; cette ttude a Ct C rCalisCe dans le cadre d'un examen gtntral des interactions drogues-protCines dans des systkmes biologiques. Qualitativement, on interprkte ces donnees en fonction d'interactions solute-solvant et solutC-solute. On discute de quelques modes plausibles pour l'hydratation des drogues et en particulier la structure des drogues. I1 existe une importante corrtlation entre les compressibilitCs adiabatiques et les possibilitts d'hydratation des moltcules en solution vis-a-vis de I'hydratation; de plus, elles semblent Stre sensibles aux caractkristiques structurales du solutt, comme la forme, la grosseur, les ramifications et la presence de noyaux aromatiques. On suggkre que ces aspects sont importants lorsqu'on veut insCrer ces solutCs dans la forme ordonnte du solvant aqueux qui entoure ces solutCs.

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Volume changes in the proton ionization of amines in water. 1. Morpholines and piperazines

Cited by 22 publications

References 12 publications

Synthesis and crystal structure of Mn(II) and Hg(II) compounds and solution studies of Mn(II), Zn(II), Cd(II) and Hg(II) compounds based on piperazinediium pyridine-2,3-dicarboxylate

Synthesis and crystal structure of Mn(II) and Hg(II) compounds and solution studies of Mn(II), Zn(II), Cd(II) and Hg(II) compounds based on piperazinediium pyridine-2,3-dicarboxylate

Partial molar volumes of some drugs in water and ethanol at 35 °C

Apparent molar volume and adiabatic compressibility studies of aqueous solutions of some drug compounds at 25 °C

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