• Bulletin of the Korean Chemical Society
• /
• v.31 no.1
• /
• pp.59-63
• /
• 2010

Calculations are presented for the $\gamma$-aminobutyric acid-$(H_2O)_n$ (n = 0-5) clusters in both canonical and zwitterionic forms. We examine the effects of microsolvation on the structures and transformation between the canonical and zwitterionic forms. The canonical forms are predicted to be more stable for n = 0-4. With five microsolvating water molecules, the two forms of $\gamma$-aminobutyric acid become quasidegenerate, with the energies of zwitterionic forms slightly (by 1 - 3 kcal/mol) higher. The lowest energy zwitterionic conformer of $\gamma$-aminobutyric acid-$(H_2O)_5$ cluster is calculated to isomerize to canonical form through a barrier-less proton transfer process and is thus predicted to be kinetically unstable. Therefore, we predict that the canonical conformers of $\gamma$-aminobutyric acid should be observed predominantly in the gas phase at low temperature in presence of up to five water molecules.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.11
• /
• pp.3797-3804
• /
• 2012

We present calculations for valine (Val) - $(H_2O)_n$ (n = 0-5) to examine the effects of microsolvating water on the relative stability of the zwitterionic vs. canonical forms of Val. We calculate the structures, energies and Gibbs free energies of the conformers at B3LYP/6-311++G(d,p), wB97XD/6-311++G(d,p) and MP2/aug-cc-pvdz level of theory. We find that five water molecules are needed to stabilize the zwitterionic form of Val. By calculating the barriers of the canonical ${\leftrightarrow}$ zwitterionic pathways of Val - $(H_2O)_5$ conformers, we suggest that both forms of Val - $(H_2O)_5$ may be observed in low temperature gas phase.

• Mycobiology
• /
• v.49 no.4
• /
• pp.434-437
• /
• 2021

In our ongoing search for new secondary metabolites from fungi, a basidiomycete fungus Irpex consors was selected for mycochemical investigation, and three new zwitterionic alkaloids (1-3) and five known compounds (4-8) were isolated from the culture broth (16 l) of I. consors. The culture filtrate was fractionated by a series of column chromatography including Diaion HP-20, silica gel, and Sephadex LH-20, Sep-Pak C₁₈ cartridge, medium pressure liquid chromatography (MPLC), and high pressure liquid chromatography (HPLC) to yield eight compounds (1-8). The structures of the isolated compounds were elucidated by the interpretation of nuclear magnetic resonance (NMR) spectra and high-resolution mass spectrometry (HR-MS). Their antioxidant and antibacterial activities were examined. The zwitterionic structures of three new sesquiterpene alkaloids (1-3) were determined together with five known compounds identified as stereumamide E (4), stereumamide G (5), stereumamide H (6), stereumamide D (7), and sterostrein H (8). This is the first report of the zwitterionic alkaloids in the culture broth of I. consors. Three new zwitterionic alkaloids were named as consoramides A-C (1-3).

• Journal of the Korean Applied Science and Technology
• /
• v.21 no.3
• /
• pp.238-245
• /
• 2004

The interaction between anion and zwitterionic surfactants was investigated by means of surface tension, NMR spectroscopy, and fluorescence studies. These systems are N-tetradecyloxymethyl-N,N-dimethyl betaine ($C_{14}$, TDB), N-octadecyloxymethyl-N,Ndimethyl betaine ($C_{18}$, ODB), and sodium dodecylethoxy sulfate (SDE). These systems show a composition dependency in micellar properties. When the molar fraction of TDB and ODB was about 0.6, the cmc values of these systems showed minima, whereas the solubilized amount of a water insoluble dye, NMR line width showed maxima. These changes comes from the intramolecular complexes formed in the mixed micelles. The complexes are due to the electrostatic interaction of oppositely charged head groups of betaine and sodium dodecylethoxy sulfate. A comparison of betaine and SDE alkyl methylene group line widths to those of n-methyl group indicates that the interior of the micelle in the restricted region is more immobile than the head group.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.798-804
• /
• 2014

We present calculations for diglycine - $(H_2O)_n$ (n = 0-3) to examine the effects of microsolvating water on the relative stability of the zwitterionic vs. canonical forms of the dipeptide. We calculate the structures, energies and Gibbs free energies of the conformers at wB97XD/6-311++G** and MP2/aug-cc-pvdz levels of theory level of theory. We predict that microsolvation by up to three water molecules does not give thermodynamic stability of the zwitterion relative to the canonical forms. Our calculations also suggest that zwitterionic diglycine - $(H_2O)_3$ is not stable kinetically in low temperature gas phase environment.

• Korean Journal of Pharmacognosy
• /
• v.9 no.4
• /
• pp.157-167
• /
• 1978

Atherosclerosis is associated with the presence of extracellular lipid droplets and large fatty deposits, both of which are to be covered at the surface mainly by zwitterionic phospholipids. The development of atherosclerosis is often associated with the accumulation of calcium. Furthermore, the presence of glycosaminoglycans directly underlying fatty deposits in human aorta has been demonstrated. Also, the possible involvement of the interaction between sulfated polysaccharide and lipoprotein in the development of atherosclerosis has been suggested in view of the presence of both low density lipoproteins and glycosaminoglycans, as well as their complexes, in atherosclerotic aortas. Therefore interactions of sulfated polysaccharides with low density lipoproteins which serve as a vehicle for cholesterol and cholesterol ester and with zwitterionic phospholipids have been studied extensively by a number of workers to provide mechanisms. In this paper, the mechanism of the interaction of sulfated polysaccharides with low density lipoproteins and the mechanism of the interaction between sulfated polysaccharides and zwitterionic phospholipids are reviewed. The possibility of the occurence of these interactions in the body are also considered.

• Journal of Industrial and Engineering Chemistry
• /
• v.67
• /
• pp.187-198
• /
• 2018

Clay based coating with zwitterionic functionality is used to remove cationic and anionic dyes. Adsorbent coating was prepared by the mixing of bentonite clay, acrylic polymer (AP) and polyethylene-diamine (EPI-DMA). Characterization was performed using SEM-EDX, XRF, X-ray mapping and FTIR analyses. The adsorption capacity of ZACC was found to be increased from 59.35 to 255.99 mg/g and from 45.84 to 70.09 mg/g for BG and AR1 dyes, respectively using initial concentration (50-200 ppm). Significant adsorption capacity along with mechanical and chemical stability formulates ZACC as an excellent composite coating for treatment of anionic and cationic dyes from industrial wastewater.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.12
• /
• pp.2355-2360
• /
• 2008

• Bulletin of the Korean Chemical Society
• /
• v.34 no.9
• /
• pp.2616-2622
• /
• 2013

A novel zwitterionic monomer 3-[(2-acrylamido)dimethylammonio]propanesulfonate (DMADAS) was designed and synthesized in this study. Then it was polymerized with acrylamide (AM) by free radical polymerization in 0.5 mol/L NaCl solution with ammonium persulfate ($(NH_4)_2S_2O_8$) and sodium sulfate ($NaHSO_3$) as initiator. The structure and composition of DMADAS and acrylamide-3-[(2-acrylamido)-dimethylammonio]propanesulfonate copolymer (P-AM-DMADAS) were characterized by FT-IR spectroscopy, $^1H$ NMR and elemental analyses. Isoelectric point (IEP) of P-AM-DMADAS was tested by nanoparticle size and potential analyzer. Solution properties of copolymer were studied by reduced viscosity. Antipolyelectrolyte behavior was observed and was found to be enhanced with increasing DMADAS content in copolymer. The results showed that the viscosity of P-AM-DMADAS is 5.472 dl/g in pure water. Electrolyte was added, which weakened the mutual attraction between sulfonic acid group and quaternary ammonium group. The conformation became loose, which led to the increase of reduced viscosity. The ability of monovalent and divalent cation influencing the viscosity of zwitterionic copolymer obeyed the following sequence: $Li^+$ < $Na^+$ < $K^+$, $Mg^{2+}$ < $Ca^{2+}$ < $Ba^{2+}$, and that of anion is in the order: $Cl^-$ < $Br^-$ < $I^-$, $CO{_3}^{2-}$ > $SO{_3}^{2-}{\approx}SO{_4}^{2-}$.

• Journal of the Korean Electrochemical Society
• /
• v.24 no.3
• /
• pp.35-41
• /
• 2021

In this study, the effect of zwitterionic surfactant on Cu electrodeposition was investigated through cyclic voltammetry. With the addition of (dodecyldimethylammonio)propanesulfonate (DDAPS) as a representative zwitterionic surfactant in the electrolyte for Cu electrodeposition, the electrochemical Cu²⁺ reduction was inhibited on Cu and glassy carbon electrodes. Its inhibition effect was similar to that of cationic surfactant rather than anionic surfactant. Moreover, DDAPS interacted with chloride ion and exhibited the mass transfer-dependent inhibition behavior, which indicates that its inhibition function is associated with the formation of its surface aggregates on anion-covered Cu surface. In addition, adsorbed DDAPS slightly reduced the surface roughness of Cu electrodeposits. These characteristics were similar to those of cationic surfactant, but less obvious. It means the effect of DDAPS on Cu electrodeposition originates from the cationic head group which is shield by anionic head group.