Heteroarm star copolymers with polystyrene and poly(tert-butyl acrylate) arms are studied in dilute solutions by means of viscometry and static light scattering. In a weakly selective solvent a segregated-nonsegregated con formational transition is observed induced by temperature change. In a strongly selective solvent association phenomena take place and the heteroarm star molecules form multimolecular micelles.

The ␣,␤-dithiol 2,3-dimercapto-1-propanol (dimercaprol or British Anti-Lewisite, BAL) reacts with AsCl 3 , in a 1:1 molar ratio, giving the expected cyclic adduct 1 but with As 2 O 3 and with AsCl 3 , in 2:3 As/BAL molar ratios, gave gums composed of many compounds. BAL reacts with Sb 2 O 3 in DMSO but the products could not be isolated. With SbCl 3 two products 2 and 3 have been isolated in 1:1 and 2:3 Sb/BAL molar ratios. Bi 2 O 3 in 1:1 and 2:3 molar ratios gave compounds 4 and 5. However, BiCl 3 and Bi(NO 3 ) 3 ·5H 2 O in either 1:1 or 2:3 stoichiometries gave compounds 6 and 7, respectively, indicating that the >Bi-Cl and >Bi(NO 3 ) bonds were not reactive towards excess BAL. The 1 H and 13 C NMR spectra of the Sb(III) and Bi(III) complexes in DMSO-d 6 revealed broad signals attributed to the quadrupole relaxation of Sb and Bi nuclei. No relaxation was observed for the arsenic complex 1 in CD 3 OD. Other properties of the complexes are presented and discussed. Fig. 1. A: Proposed structure for the interaction of arsenite with closely spaced thiols in a steroid receptor [11]; B: A 6-membered ring in the adduct DHLA/As-Ph; C: Proposed formula for the adduct BAL/lewisite; D: Formula of the adduct BAL/As-Ph.Because monofunctional thiols in excess do not reverse the effect of lewisite or NaH 2 AsO 3 , Sir Rudolf Peters introduced the dithiol 2,3-dimercapto-1-propanol (dimercaprol or British Anti-Lewisite, BAL) as an antidote for lewisite [34,47,48]. BAL efficiently and quickly reversed the effects of lewisite in cells and keratin [34,47] and of (Ar-AsO) x on DHLA of E. coli [46]. Conversely, excess BAL is toxic because it can inactivate proteins and enzymes containing disulfide groups or heavy metal prosthetic groups, e.g. catalase, peroxidase, carbonic anhydrase [47] and has other drawbacks, e.g. the BAL-As(III) complexes are distributed to other organs such as the brain [48].An attempt was make in 1968 to measure the dissociation constant of the arsenite complex of DHLA [50] and in 2005 it was shown that a particularly stable 2:3 As:DHLA complex was formed [45] but a formula for it was not proposed. However, a model for the interaction of NaH 2 AsO 3 with closely spaced thiols in steroid receptor was proposed [11] (A in Fig. 1), while the phenyl dithioarsonate adduct of DHLA has been established as having a six-membered ring, (B in Fig. 1) [14,49]. The formula for the product of the reaction of BAL with lewisite was proposed by Peters (C in Fig. 1) [34,47] and the feasibility of forming a five-membered ring was proven with the adduct (D in Fig. 1) by X-ray and by 1 H and 13 C NMR for other organoarsenicals [1]. Because arsenite forms a stronger complex with BAL than with 1,3-dithioglycerol [50], the reversal of the inhibition of DHLA by arsenite and lewisite after administration of BAL can be understood. Antimony(III) resembles As(III) in its chemistry and biochemistry in that it has an affinity for -SH groups. Its sodium and potassium tartrate salts are powerful emetics [19]. These two salts and other antimoni...

Propargyl chloride, CH ≡ C-CH 2 Cl, was virtually inert towards NaH 2 AsO 3 , reacted to a very small extent with Na 2 HAsO 3 , but with Na 3 AsO 3 gave a mixture of salts in which sodium 1-propynylarsonate, CH 3 -C≡C-AsO 3 Na 2 6, predominated, the allenylarsonate, CH 2 = C = CH-AsO 3 Na 2 4, being present in (very) small amounts, while the isomeric 2-propynylarsonate CH ≡ C-CH 2 -AsO 3 Na 2 5 was not detected. These results can be understood by attack of AsO 3 3on propargyl chloride to form 5 followed by base catalyzed prototropic rearrangements to 4 and to 6. Separation of 6 from 4 was tried as acids or salts without success. The purity of the product as acid 6 and lead salt of 6 was >80%. The reaction of propargyl chloride with Na 2 SO 3 required dilute aqueous solutions (∼0.3 M) in order to give the salt CH ≡ C-CH 2 -SO 3 Na•4H 2 O, 11•4H 2 O, in ∼80% yields. More concentrated solutions (1 or 2 M) produced 11 and by-products from which CH 2 = C = CH-SO 3 Na 10, but not CH 3 -C ≡ C-SO 3 Na 12, has been identified spectroscopically, while potassium 2-chloro-2-propenylsulfonate tetrahydrate CH 2 = CCl-CH 2 -SO 3 K•4H 2 O, 13•4H 2 O, was isolated.