The membrane as an environment of minimal interconversion. A circular dichroism study on the solvent dependence of the conformational behavior of gramicidin in diacylphosphatidylcholine model membranes

Biochemistry ◽  
1988 ◽  
Vol 27 (13) ◽  
pp. 4848-4855 ◽  
Author(s):  
J. Antoinette Killian ◽  
Kari U. Prasad ◽  
Dorothy Hains ◽  
Dan W. Urry
Keyword(s):  
Circular Dichroism ◽  
Model Membranes ◽  
Conformational Behavior ◽  
Solvent Dependence ◽  
Circular Dichroïsm

Circular dichroism spectra of tetraamminecobalt(III) complexes of amino alcohols

1978 ◽  
Vol 31 (11) ◽  
pp. 2399 ◽  
Author(s):  
CJ Hawkins ◽  
GA Lawrance ◽  
JA Palmer
Keyword(s):  
Circular Dichroism ◽  
Chemical Shift ◽  
Chemical Shifts ◽  
Amino Alcohols ◽  
Circular Dichroism Spectra ◽  
Chemical Shift Difference ◽  
Solvent Dependence ◽  
Cotton Effects ◽  
Circular Dichroïsm ◽  
Chiral Amino Alcohols

The circular dichroism spectra are reported for tetraamminecobalt(III) complexes with the chiral amino alcohols 2-aminopropan-1-ol, 2- aminobutan-1-ol, 1-aminopropan-2-ol, 2-amino-1-phenyl-ethanol, ψ- ephedrine and ephedrine with the alcohol groups protonated (OH) and deprotonated (O-). The solvent dependence of the chemical shifts of the NH protons was investigated to determine the effects of stereoselective solvation on the circular dichroism, but, in contrast to some other related systems, the chemical shift difference between the two NH2 protons was relatively insensitive to solvent. Consistent with this, the circular dichroism spectra of the tetraphenylborate salts of the deprotonated complexes were found not to be markedly dependent on solvent. Tetraammine-{(-)-ψ-ephedrine)cobalt(III) and tetraammine{(-)- ephedrine}cobalt(III) were found to have the same signs of Cotton effects for the various d-d transitions, whereas bis{(-)-ψ- ephedrine}copper(II) and bis{(-)-ephedrine}copper(II) had opposite signs. This has been explained in terms of different conformer populations in the cobalt(III) and copper(II) systems.

Solvent-dependent circular dichroism of trans-disubstituted Bis(R-propane-1,2-diamine)cobalt(III) complexes

1977 ◽  
Vol 30 (10) ◽  
pp. 2115 ◽  
Author(s):  
CJ Hawkins ◽  
GA Lawrance ◽  
RM Peachey
Keyword(s):  
Circular Dichroism ◽  
Metal Ion ◽  
Ion Association ◽  
Positive Contribution ◽  
Circular Dichroism Spectra ◽  
Hydrogen Bond Formation ◽  
Rotational Strength ◽  
Solvent Dependence ◽  
Halide Salts ◽  
Circular Dichroïsm

The circular dichroism spectra of trans-disubstituted bis(R-propane- 1,2-diamine)cobalt(III) complexes are reported for an extended series of solvents. The observed variations in the spectra of the dichloro and dibromo complexes are analysed in terms of stereoselective solvation at the diamine N-H protons, and also the ion association between the complexes and their counter-ions. The solvation of these dihalo complexes, which was studied by p.m.r., showed a preference for hydrogen-bond formation with the equatorial N-H protons, rendering the donor nitrogens asymmetric and thus introducing a new source of dissymmetry close to the metal ion chromophore. This affected a decrease in the positive rotational strength of the 1A1g → 1Eg (D4h) transition, and a positive contribution to the rotational strength of the 1A1g → 1A2g (D4h) component. Ion association of the dihalo complexes was evaluated by a comparison of the circular dichroism of the tetraphenylborate and halide salts. ��� The tendency for ion association was much greater for the tripositive diammine complex. However, stereospecific solvation was of little importance and the circular dichroism spectra did not show any marked solvent dependence for the tetraphenylborate salt.

scholarly journals Oriented Synchrotron Radiation Circular Dichroism and Linear Dichroism Spectroscopy of Peptides in Model Membranes

2009 ◽  
Vol 96 (3) ◽  
pp. 337a ◽  
Author(s):  
Barbara Perrone ◽  
Andrew J. Miles ◽  
Burkhard Bechinger ◽  
Soren Vronning Hoffman ◽  
B.A. Wallace
Keyword(s):  
Circular Dichroism ◽  
Synchrotron Radiation ◽  
Linear Dichroism ◽  
Model Membranes ◽  
Circular Dichroïsm

Circular Dichroism Spectra of Cobalt(III), Platinum(II) and Molybdenum(0) Complexes of 1-Phenylethane-1,2-diamine

1979 ◽  
Vol 32 (7) ◽  
pp. 1433 ◽  
Author(s):  
CJ Hawkins ◽  
ML McEniery
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Spectra ◽  
Conformational Effect ◽  
Solvent Dependence ◽  
Circular Dichroïsm

The circular dichroism spectra are presented for the complexes, trans-[CoL2C12]+, trans-[CoL2Br2]+, [CoL(NH3)4]3+, [CoL(CN)4]-, [MoL(CO)4] and [PtL(py)2]2+, where L is (R)-1-phenylethane-l,2- diamine, in a number of solvents. The solvent dependence of the spectra for the cobalt(m) complexes has been analysed in terms of stereoselective solvation of the diamine N-H protons. The spectra are compared with those of the analogous (R)-propane-1,2-diamine complexes. This comparison shows that the so-called 'conformational effect' is not predominant.

scholarly journals Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

2019 ◽  
Vol 15 ◽  
pp. 1913-1924 ◽  
Author(s):  
Bartosz Setner ◽  
Agnieszka Szumna
Keyword(s):  
Circular Dichroism ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Chiral Amines ◽  
Chirality Transfer ◽  
Polar Environment ◽  
Solvent Dependence ◽  
First Choice ◽  
Polar Media ◽  
Circular Dichroïsm

Directional self‐assembly of conformationally well-defined complexes in polar environment is still a major challenge in supramolecular chemistry. In the present study we demonstrate that resorcin[4]arene sulfonic acid (RSA) interacts with chiral amines (amino acid derivatives and aminocavitands) to form inclusion complexes and capsules based on electrostatic interactions. The complexes were characterized by circular dichroism and DOSY NMR spectroscopy. Chirality transfer from amines onto a resorcinarene skeleton was manifested by the appearance of signals in CD spectra and diastereotopic splitting in NMR spectra. The complexes proved to be thermodynamically stable in methanol, but DMSO and methanol/water mixtures were found to be highly disintegrative for these complexes. This result is quite non-intuitive and worth attention in the context of formation of supramolecular complexes in polar environment, for which DMSO is most often a first-choice solvent.

scholarly journals Solvent Dependence of the Circular Dichroism Spectra of Somecis-Dianionobis(ethylenediamine)cobalt(III) Complexes

1982 ◽  
Vol 55 (6) ◽  
pp. 1862-1868 ◽  
Author(s):  
Ushio Sakaguchi ◽  
Hiroshi Nakazawa ◽  
Kazuhisa Sakai ◽  
Hayami Yoneda
Keyword(s):  
Circular Dichroism ◽  
Circular Dichroism Spectra ◽  
Solvent Dependence ◽  
Circular Dichroïsm
Sign in / Sign up

Export Citation Format

Share Document