Yu. M. Polikarpov

CORRELATION ANALYSIS OF ARYLIC STRENGTHENING OF THE EXTRACTION CAPACITY OF BIDENTATE ORGANOPHOSPHORUS EXTRACTANTS

This paper is devoted to the so-called effect of “anomalous arylic strengthening” (AAS) observed upon extraction of a series of elements, mainly actinides and lanthanides, by bidentate neutral organophosphorus compounds (BNOPC). This “anomalous” effect is an increase in the extraction capacity of a reagent when alkyl substituents at the phosphorus atom are replaced with more electronegative aryl groups. The influence of phenyl substituents at the phosphorus atom on the reactivity of organophosphorus compounds of various types was considered. Based on the data on electronic effects of substituents, hypotheses were formulated about the reasons for AAS involving phenyl groups that are biphilic because they have substituents capable of manifesting both donor and acceptor properties depending on several factors such as,e.g., the nature of the reaction center, the character of the attacking reagent, the nature of the solvent,etc. When a strong complex of a metal with a phenyl substituted reagent of BNOPC is formed during extraction, the phenyl groups become donating, and additional strengthening of the complex appears.

N-Substituted 2-aminoethylidenediphosphonic acids as complexones

A novel complexone, 2-dimethylaminoethylidenediphosphonic acid, was synthesized. Its acid-base and complexation properties were studied by potentiometric titration in aqueous solutions (25 °C) and compared to those of 2-amino-1-hydroxyethylidenediphosphonic acid and ω-aminoalkylidenediphosphonic analogs. Parameters of efficiency and selectivity of complexation were determined. The influence of the alkylidene chain length on complexone properties in a series of ω-aminoalkylidenediphosphonic acids was analyzed.

NewN-substituted 1-hydroxy-3-aminopropylidenediphosphonic acids

N-Substituted 1-hydroxy-3-aminopropylidenediphosphonic acids were synthesized. Their acid-base and complexation properties toward a wide series of metal cations in water were investigated.

Spectroscopic study of copper(II) complexes with 1,4,7-tris(dihydroxyphosphorylmethyl)-1,4,7-triazacyclononane and 1,4,7-tris(β-dihydroxyphosphorylethyl)-1,4,7-triazacyclononane

The reaction of 1,4,7-tris(dihydroxyphosphorylmethyl)-1,4,7-triazacyclononane and 1,4,7-tris(β-dihydroxyphosphorylethyl)-1,4,7-triazacyclononane with divalent copper over a wide pH range in aqueous solution has been studied using electronic, vibrational, and ESR spectroscopy. Normal and protonated complexes of both compounds have a pentacoordinate structure of the tetragonal type with coordination of three nitrogen atoms and two phosphonic groups. The difference lies in the different degree of distortion and flexibility of the square-pyramidal polyhedron.

New cyclopendant organophosphorus complexing agent-1,4,7,10-tetrakis (β-dihydroxyphosphorylethyl)-1,4,7,10-tetraazacyclododecane

The synthesis is described and the mechanism of acid dissociation is found by31P NMR spectroscopy. Stability constants for a large number of cations are determined. A high selectivity for complexation toward Cu2+, Zn2+, Cd2+, and Hg2+ ions is found.

Synthesis and acid-base and complexing properties of amino-substituted?-hydroxyalkylidenediphosphonic acids

1. We have synthesized new amino-substitutedα-hydroxyalkylidenediphosphonic acids. 2. We have measured the acid dissociation constants of these compounds and the stability constants of their complexes with Ca2+, Co2+, and Cu2+ ions.

Phosphine oxides and phosphorous acids containing several>P(O)CH2 groups in the molecule

1. The synthesis of polymethylenepolyphosphine compounds was accomplished by the condensation of the esters of trivalent phosphorus acids with the oxides of tertiary bis- and tris(chloromethyl)phosphines and the esters of bis(chloromethyl)phosphinic acid. 2. The metalation of pentaphenyldimethylenetriphosphine trioxide gave the potassium derivatives, the anions of which have a mesomeric structure, with a distribution of the charge between the oxygen and carbon atoms of the methine groups. 3. Phenyldistyrylphosphine oxide and diphenylphosphinic acid are formed when the dipotassium derivative of pentaphenyldimethylenetriphosphine trioxide is reacted with benzaldehyde.

Protonation of triethyl (2-pyridylimido)phosphates

Protonation of triethyl (2-pyridylimido)phosphates has been studied by potentiometric titration in nitromethane, IR and NMR spectroscopy, and X-ray structure analysis. The substances studied are protonated in one step at the N-atom of the pyridine ring. The protonated cations may be represented, according to the X-ray data, as a resonance of two structures: pyridinium and pyridoniminium; the contribution of the latter probably being considerable. Changes in spectral parameters of POEt groups upon protonation of pyridylimidophosphates (PIP) have been noted.

A new organophosphorus pyridine complexone — 2,6-bis (dihydroxyphosphorylmethyl)pyridine

Conclusions1.A new organophosphorus complexone, containing a pyridine fragment, was synthesized. The acid-base and complexing properties of alkaline earth and transition metal ions were studied. The composition of the complexes formed was found to be 1:1.2.The introduction of the pyridine fragment into the complexone synthesized leads to an increase in the complexation selectivity.

?-Hydroxy-?-[N,N-bis(dihydroxyphosphorylmethyl)-amino]propylidenediphosphonic acid as a complexone

Conclusions1.α-Hydroxy-γ-[N,N-bis(dihydroxyphosphorylmethyl)amino]propylidenediphosphonic acid was synthesized, and its pKa values for dissociation and the stability constants of complexes with a number of alkaline earth and transition metals were determined. The presence of both hydroxyalkylidenediphosphonic and iminobis(methylphosphonic) acid fragments in the molecule of the investigated complexone increases the stabilities of the complexes.2.The synthesized acid has a zwitter-ion structure, and the betaine proton dissociates last.