Selenium carboxylic acids betaine; 3,3′,3″-selenotris(propanoic acid) betaine, Se(CH 2 CH 2 COOH) 2 (CH 2 CH 2 COO)

Abstract

Attempts to prepare [Se(CH 2 CH 2 COOH) 3 ] + Clfrom Se(CH 2 CH 2 COOH) 2 and H 2 C=CHCOOH in concentrated hydrochloric acid, for the corresponding sulfonium salt, led exclusively to the Se-betaine, Se(CH 2 CH 2 COOH) 2 (CH 2 CH 2 COO). The Se-betaine crystallises in the space group P2 l /c with the cell dimensions at 223 K, a = 5.5717(1), b = 24.6358(4), c = 8.4361(1) Å, β = 104.762(1)°, V = 1119.74(3) Å 3 , Z = 4, D calc = 1.763 Mgm-3 , µ = 3.364 Mm-1. The structure refined to R I = 0.0223 for 2801 reflections with F o > 4σ(F o). In the crystalline state the molecule is intermolecularly linked to neighbouring molecules by a number of hydrogen bonds; a very strong carboxylic-carboxylate bond with an O••••O distance of 2.4435(16) Å, a medium strong carboxylic-carboxylate bond with an O••••O distance of 2.6431(16) Å and several weak O••••H(CH 2) with O••••C distances between 3.2 and 3.3 Å. In the carboxylic group involved in the very strong hydrogen bond the O••••H bond is antiperiplanar to the C=O bond while the O-H bond is periplanar to the C=O bond in the second carboxylic group. Based upon the CO bond lengths and the elongation of the O-H bond involved in the strong hydrogen bond one may describe the compound as strongly linked units of Se(CH 2 CH 2 COOH)(CH 2 CH 2 COO) 2 rather than Se(CH 2 CH 2 COOH) 2 (CH 2 CH 2 COO). The selenium atom forms two strong intramolecular 1,5-Se••••O contacts, with a carboxylate oxygen atom, 2.9385(12) Å, and with a carboxylic oxygen atom, 2.8979(11) Å. To allow for these contacts the two organic fragments have been forced into the periplanar conformation. The molecule is only slightly asymmetric with regard to the C-Se-C bond angles but is very asymmetric with regard to the torsion angles.

Polydopamine-Based Nanocomposite as a Biomimetic Antioxidant with a Variety of Enzymatic Activities for Parkinson’s Disease

“…The Fourier transform infrared (FTIR) spectra of the two materials showed obvious characteristic absorption peaks of PDA NPs at 1610 and 1510 cm –1 for the stretching vibration absorption peaks of the benzene ring and at 1250 cm –1 for the C–O stretching vibration peak and O–H deformation vibration, as shown in Figure e . The absorption peak appearing at 636 cm –1 after the addition of SeCys was due to a C–Se bond . According to the above results, it can be proved that SeCys was successfully introduced into the NPs.…”

“…24 The absorption peak appearing at 636 cm −1 after the addition of SeCys was due to a C−Se bond. 25 According to the above results, it can be proved that SeCys was successfully introduced into the NPs. Scanning electron microscopy (SEM, Figure 1f,g) showed that the two NPs were spherical with uniform size and good dispersion.…”