An imidazolium-based zwitterion containing two oxyethylene units was obtained as a colorless liquid at room temperature. The equimolar mixture of the liquid zwitterion and lithium bis(trifluoromethylsulfonyl)amide showed an ionic conductivity of over 10(-4) S cm(-1) at 80 °C, which was higher than those of mixtures composed of analogous solid zwitterions.

Zwitterionic and canonical isomers of a novel quinonoid species were studied using second-order Møller–Plesset perturbation theory with 6-31+G**+5(sp)4d basis sets. An experimental report on the zwitterion being the most stable isomer was confirmed. In particular, the zwitterionic isomer is lower than the lowest canonical tautomer by 1.42 kcal/ mol. Binding an electron to all isomers studied wa...

Modification of peptide sequence offers versatile control over their self-organization capability within adlayers adsorbed on surfaces. However, to gain full the self-organization, clear links between and lateral ordering in these must be established. Using molecular dynamics simulations WA or AW dipeptides, spontaneous emergence ordered nano-patterns containing neutral, zwitterion, neutral-zwi...

The indole based zwitterion 2 forms stable dimers held together by H-bond assisted ion pairs. Dimerisation was confirmed in the solid state and studied in solution using dilution NMR experiments. Even though zwitterion 2 forms very stable dimers even in DMSO, their stability is lower than of an analogous pyrrole based zwitterion 1. As revealed by the X-ray crystal structure the two binding site...

The designs of potent neuraminidase (NA) inhibitors are an efficient way to deal with the recent "2009 H1N1" influenza epidemic. In this work, density functional calculations were employed to study the conformation, stability and formation of the zwitterions of 5-[(1R,2S)-1-(acetylamino)-2-methoxy-2-methylpentyl]-4-[(1Z)-1-propenyl]-(4S,5R)-d-proline (BL), a proline-based NA inhibitor. Compared...

A spectroscopic study of L-α-alanine in different environments is presented, with special emphasis on the neutral to zwitterion transformation of this amino acid. Spectra of room temperature solids as deposited from the vapour and in KBr pellets are compared and discussed revealing some discrepancies. An assignment is proposed based on theoretical calculations of the solid structure. Vapour dep...

This work explores the reactivity of a reversible superbase–CO 2 zwitterion, which can be used as stoichiometric source CO .

Tryptophyl glycine (TrpGly) and glycyl tryptophan (GlyTrp) dipeptides at pH 5.5 and pH 9.3 show a pattern of fluorescence emission shifts with the TrpGly zwitterion emission solely blue shifted. This pattern is matched by shifts in the UV resonance Raman (UVRR) W10 band position and the W7 Fermi doublet band ratio. Ab initio calculations show that the 1340 cm(-1) band of the W7 doublet is compo...

The zwitterionic tautomers of isolated amino acids have not been identified in the gas-phase despite serious experimental efforts.1,2 The main reason is that a typical OH bond is stronger than a NH bond by ca. 17 kcal/mol,3 and thus the canonical tautomer is lower in energy. Indeed, numerous ab initio calculations have confirmed the energy preference for canonical tautomers H2N-CHR-COOH in the ...

The arginine parent anion was generated by a newly developed, infrared desorption-electron photoemission hybrid anion source. The photoelectron spectrum of the arginine anion was recorded and interpreted as being due to dipole binding of the excess electron. The results are consistent with calculations by Rak, Skurski, Simons, and Gutowski, who predicted the near degeneracy of arginine's canoni...