Alkali metal complexes polyamines

A. W. Laager, ed., "Polyamine Chelated Alkali Metal Complexes," Chem. Ser. 130 (1974). 

Table 4 Polyamine-chelated Alkali Metal Complexes for which X-Ray Structural Data...

Modem work on these and related bare post-transition element clusters began in the 1960s after Corbett and coworkers found ways to obtain crystalline derivatives of these post-transition element clusters by the use of suitable counterions. Thus, crystalline derivatives of the cluster anions had cryptate or polyamine complexed alkali metals as countercations [8]. Similarly, crystalline derivatives of the cluster cations had counteractions, such as AlCLj, derived from metal halide strong Lewis acids [9]. With crystalhne derivatives of these clusters available, their structures could be determined definitively using X-ray diffraction methods. 

Beryllium in tap water, dialysis fluids and alkali-metal salts was determined with Chrome Azurol S after preconcentration of the complex on a column packed with polyethylene powder [1]. Sorption preconcentration of Be on a fibrous sorbent (poly(acrylonitrile)-carboxylated polyethylene-polyamine) prior to the determination of metal with Arsenazo I in sea water was described [2]. 

Information about physicochemical and complexation properties of polyvinylsulfonic acid (PVSH) or, more correctly, polyethylenesulfonic acid (PESH) [11] is much less available than that of the polyamines. PVSH (or PESH) is a simple, strong polyacid (see Fig. 6.6), so that partial ionization and possible hydrolysis effects, encountered with weak polyacids and their salts (e.g., polyacryfic acid and its salts), do not complicate the picture [76]. Commercially available sodium salt, PVSNa, is a brittle hygroscopic solid, soluble in water, but insoluble in organic solvents (methanol, dioxane, etc.) [77]. Viscosity behavior of the alkali metal salts was studied by several groups [28, 52, 75-77], but data are too scattered to be trustworthy. The PVS polyanion shows a definite selectivity in ion binding with alkali Li, Cs metals in the presence of Na, K hah des [78]. 

The closely related research on polyether chelates by Michal Szwarc and his co-workers led to a detailed determination of the structure and properties of carbanions in ion pairs and free ions. The fundamental principles which were developed and clarified in their numerous publications contribute to an understanding and interpretation of much of the polyamine chelate work as well. More recently the crown ether chelates, pioneered by Pederson and co-workers at the Dupont Laboratories, have given additional impetus to research on chelated alkali metal compounds. Crown ethers and amines are cyclic variations which can provide greater stability and specificity in complexation of cations, particularly the heavier alkali metal ions. 

Our background with chelate complexes suggested the use of Group IA and IIA metal salts for selective polyamine complexation. The specificity of the interaction between alkali-metal and alkaline-earth salts and certain polyamines provides a sensitive technique for separating single polyamines from multicomponent samples. These separations, the factors that affect complex formation, and the unique properties of the poly-tertiary amine chelates of inorganic lithium compounds are discussed in this paper. 

The data in Table V were obtained by sequential treatment of the initial sample with sodium iodide and lithium chloride. Complexation with sodium iodide was done in a heptane-benzene slurry. The sparingly soluble sodium iodide chelate was isolated by filtering the mixture. The remaining solution was concentrated, and the residue obtained was contacted with lithium chloride in pentane. After stirring this heterogeneous mixture, a solid lithium chloride chelate complex was isolated by filtration. Decomposition of the alkali-metal salt complexes followed by recovery and analysis of the polyamine components showed that the sodium iodide complex contained 82.6% n-HMTP while the LiCl complex contained 94.8% N,N -c-PMPP. Table V shows that the initial polyamine sample contained 48.8 and 11.4% of these ligands, respectively. 

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