Synthesis and Ionophoric Properties of α,ω-Diphosphorylated Aza Podands: II. Kabachnik-Fields Reaction as a Method for Design of α,ω-Diphosphorylated Aza Podands and Their Use for Determination of Metal Ions

Abstract

Methods of the design of podands with a-aminomethylphosphine oxide terminal groups with the purpose of investigation of the ionophoric properties of the podands and their use as components of ion-selective electrodes are analyzed. The most convenient procedure is a one-pot synthesis based on the Kabachnik3 Fields reaction in a system comprising a dialkyl(aryl)phosphinous acid, formaldehyde, and a diamine. An alternative procedure is two-stage and involves the reaction of a primary amine with a phosphinous acid and formaldehyde to form an a-aminomethyldialkyl(aryl)phosphine oxide in the first stage and cross-linking of two molecules of this compound via reaction with a dihalooligoether of the corresponding length in the second. Advantages and disadvantages of both procedures are considered. Electrode-active properties of the prepared aza podands are studied to show that ion-selective electrodes on their basis can be used for selective determination of low concentrations of alkali and alkaline-earth metal ions.One of the most promising fields in the chemistry of host3guest complexes is design of polyfunctional host molecules with preset properties, capable of effectively binding inorganic and organic molecules. Various complex-forming agents that can play the role of a host are nowadays used in ion-selective electrodes, membrane transport, and as biologically active compounds, catalysts, etc. Podands with donor terminal groups hold much promise in this respect [2]. Of them the most extensively studied are oligoethers with amino and amido terminal groups [3], that have found wide application as components of ion-selective electrodes for metal cations [4,5]. Considerable recent attention has been attracted to podands with phosphine oxide and phosphonate terminal groups, as potent complex-forming agents for alkali metal cations and effective neutral carriers and extractants for rare-earth metals [439]. The available published data on the complex-forming ability of aminophosphonates and aminophosphine oxides suggest that these compounds, too, may serve as effective reagents for extraction and separation of metal ions [9, 10].At the same time, the information on the synthesis ÄÄÄÄÄÄÄÄÄÄÄÄ 1 For communication I, see [1].

Microwave-assisted synthesis of N,N-bis(phosphinoylmethyl)amines and N,N,N-tris(phosphinoylmethyl)amines bearing different substituents on the phosphorus atoms

“…(Phenylaminomethyl)dibenzylphosphine oxide was prepared by the three-component reaction of aniline, paraformaldehyde and dibenzylphosphine oxide [7], as well as by the reaction of (hydroxymethyl)dibenzylphosphine oxide and aniline [8]. The condensation of butylamine, paraformaldehyde and di( p -tolyl)phosphine oxide to afford (butylaminomethyl)di( p -tolyl)phosphine oxide was also described [9]. A microwave (MW)-assisted, catalyst-free method was elaborated by us for the synthesis of several (aminomethyl)phosphine oxides [10–11].…”