Synthesis and characterization of polymer-bound selenium coronands: enhancing the stability of reactive dications by restricting intermolecular interactions

Abstract

Abstract:The stepwise synthesis of 1,5,9,13-tetraselenacyclohexadecan-3-017 from the reaction of sodium propane-1,3-bisselenolate-2-01 with 4.8-diselenaundecan-1,ll -di-p-toluenesulfonate 5 in THF and ethanol in 62% yield is described. Compound 5 is obtained from the corresponding diol3, which is obtained, in turn, from the reaction of sodium propane-1,3-bisselenolate with two equivalents of 3-chloropropanol. 1,5-Diselenacyclooctan-3-019 and 1,5,9,13-tetraselenacyclohexadecan-3,l I-diol 10 are obtained in yields of 43% and 1 I%, respectively, from the one-step reaction of sodium propane-1,3-bisselenolate-2-01 with 1,3-dibromopropane. Polymers with pendant selenium coronands, 1,5-diselenacyclooctane (8Se2) and 1,5,9,13-tetraselenacyclohexadecane ( 16Se4), have been prepared by free radical polymerization of the corresponding selenium coronands 9 and 7, derivatized as their acryloyl esters 11 and 12. Copolymers of methyl acrylate and 3,7-diselenacyclooctyl acrylate 11 have also been prepared in analogous fashion. The polymers have been characterized by 'H and I3C NMR, IR, and UV-visible spectroscopy. The redox chemistry of polymer-bound selenium coronands in solution, and in the form of thin films coated on electrodes, has been determined by electrochemical methods. Selenium coronands attached to the polymer chain exhibit enhanced oxidative stability compared to monomeric analogues, presumably because restrictive motion of polymerbound moieties inhibits inter-and intra-molecular degradation reactions. Electroactivity of polymer-modified electrodes is restricted to a few monolayers close to the electrode surface. Spatial separation of coronands along the chain, achieved by copolymerization with electro-inert methyl acrylate, gave copolymer-modified electrodes that possessed even greater redox stability than their corresponding homopolymers. Furthermore, by blending electro-inert poly(methy1 acrylate) with electroactive selenium coronand copolymers, polymer-modified electrodes that possessed superior electrochemical stability were obtained.Key words: selenium coronands, polymers, electrochemistry, dications.Resume : On dCcrit la synthkse par Ctape (rendement de 62%) du 1,5,9,13-tCtrasC1CnacyclohexadCcan-3-ol,7, rCalisie par rtactions par Ctapes du propane-l,3-bissC1Cnolate-2-01 de sodium avec le di-I>-toluknesulfonate de 4,s-disC1CnundCcan-1,11-diyle, 5, dans le THF et I'Cthanol. On obtient le composC 5 a partir du diol3 correspondant qui est obtenu, j . son tour, par la rCaction du propane-1.3-bissC1Cnolate de sodium avec deux Cquivalents de 3-chloropropanol. Les I ,5-disClCnacyclooctan-3-0l,9, et 1,5,9,13-tCtrasClCnacyclohexadCcan-3,l I -diol, 10, ont Ct C obtenus avec des rendements respectifs de 43% et de I 1 % par des rCactions en une Ctape du propane-1.3-bissC1Cnolate-2-01 de sodium avec le 1,3-dibromopropane. On a prCparC des polymbres portant des pendants de coronands de sClCnium, 1,5-disC1Cnacyclooctane (8Se2) et 1,5,9,13-tCtrasClCnacyclohexadCcane (16Se4). en procCdant j. la polymCrisation des coronands st...

Synthesis, Characterization, and Redox Behavior of New Selenium Coronands and of Copper(I) and Copper(II) Complexes of Selenium Coronands

“…The mixture was stirred for 5 min at ambient temperature and cooled to 3 °C overnight. The crystals were collected and recrystallized from CH3CN to afford 8Se2(SO3CF3)2 (11) as white crystals (234 mg, 49%). Mp: 167-168 °C dec. 1 H NMR (CD3CN): δ 3.0-3.7 (4H, m, SeCH2CH2CH2Se), 3.9-4.3 (8H, m, CH2SeCH2CH2CH2SeCH2).…”

“…We have reported the synthesis and properties of various selenium coronands and described their metal ion complexes. [9][10][11][12][13][14][15][16] We have reported the structures of the Pd(II) complex of 1,5,9,13-tetraselenacyclohexadecane (16Se4) 13 and the Pd(II) complex of 1,5,9,13,17,21-hexaselenacyclotetracosane (24Se6). 13 We have also described a study of the adducts of 16Se4 with copper(I) triflate and mercury(II) cyanide, 14 as well as Cu(I), Cu(II), and Pd(II) complexes of other selenium coronands.…”

“…We also describe the synthesis, characterization, redox properties, and X-ray crystal structures of the Cu(II) complexes of 1,5-diselena-9,13-dithiacyclohexadecane ([Cu(16Se2S2)][SO 3 -CF 3 ] 2 (4)), cis-1,5,9,13-tetraselenacyclohexadecane 2 )][SO 3 CF 3 ] 2 (5)), and 1,5-diselenacyclooctan-3-ol ([Cu(8Se2(OH)) 2 ][SO 3 CF 3 ] 2 (6)) and the Cu(I) complexes of 1,5-diselena-9,13-dithiacyclohexadecane ([Cu(16Se2S2)]-[SO 3 CF 3 ] ( 7)) and 1,5,9,13-tetraselenacyclohexadecan-3-ol ([Cu-(16Se4(OH))][SO 3 CF 3 ] ( 8)). The isotropic 13 C and 77 Se chemical shifts obtained in the solid state for 2, 3, 1,5,9,13-tetraselenacyclohexadecan-3,11-diol (16Se4(OH) 2 ( 9)), 11 1,5,9,13-tetraselenacyclohexadecan-3-ol (16Se4(OH) (10)), 11 and the dicationic compound 1,5-(diseleniacyclooctane trifluoromethanesulfonate (8Se2(SO 3 CF 3 ) 2 (11)) are presented, as well as the 77 Se chemical shift anisotropies for 10 and 11.…”

Synthesis, Characterization and Study of DC Electrical Conductivity of Poly[MWCNT/Imidoselenium] Composite

“…selenium has compete in not solely human health, however additionally the evolution of life, it's been found to be an important elemental semiconductor and studied as reason of its specific physical properties high photoconductivity, piezoelectricity, thermoelectricity, and nonlinear optical responses 1,2 . Modern medical research has additionally reviewed that Selenium is expounded to an inventory of human diseases such as cardiovascular disease, cancer, diabetes, and central nervous system disease 3,4,5,6,7,8,9 .…”

Selenoether macrocyclic chemistry–syntheses and ligand properties of new small-ring Se3- and Se2N-donor macrocycles

“…1−3 Despite significant progress in thioether macrocyclic chemistry, macrocycles involving the heavier selenoether and telluroether functions are much less well developed -especially potentially tridentate small rings. 2,3,5 Synthetic routes to tetraselena-and hexaselena crowns were originally reported by Pinto et al [6][7][8] and the coordination chemistry of especially [16]aneSe 4 (1,5,9,13-tetraselenacyclohexadecane) and to a lesser extent [24]aneSe 6 (1,5,9,13,17,21-hexaselenacyclotetracosane) have been developed with both d-block and p-block elements. 5,[9][10][11][12] The macrocyclic framework facilitates stabilization of unusual species such as [CrX 2 ([16]aneSe 4 )]PF 6 (X = Cl, Br or I), [NiX 2 ([16]aneSe 4 )] containing the hard, oxo-philic d 3 Cr(III) and labile d 8 Ni(II) ions respectively, 9,10 within a selenium-rich coordination environment, and trans-[PtX 2 ([16]aneSe 4 )](PF 6 ) 2 (X = Cl or Br) based upon distorted octahedral Se 4 X 2 coordinated Pt(IV).…”