Search

Individuals have a right to their images, meaning that they can decide on permitting having their photos taken or published. Therefore, the consent of the person who is the subject of an image must be obtained for photography or publication. This right, however, is not absolute and without exceptions. People have the right to know what is happening in their community. As a result, if a photo is taken of someone and published for information, it is not necessary to insist upon obtaining consent. Several legal systems allow the imaging of others for informational purposes. However, in such cases, the privacy and dignity of people must be observed, and no one is permitted to publish images insulting or contrary to the public/personal internet. Also, images must not be used for business purposes. In the Iranian legal system, the freedom of the press (principle 24 of the Constitution) and the importance of public interest and its priority over private interests (principle 40 of the Constitution) convey the same idea that the principle is to allow publishing images for informational purposes.

A linear relation between delta-H(super degree) (sub acid)(HX), EA[X(sub .)], and BDE(HX) is shown for specific classes of compounds and only one of these quantities is needed to determine the others. The intercepts obtained from plots of delta-H(super degree) (sub acid)(HX) vs EA[X(sub .)] provide bond energies which correspond to BDE(HX) when EA[X(sub .)] = 0.

The α-C-H bond dissociation energy (BDE) of phenylcyclopropane (1) was experimentally determined using Hess' law. An equilibrium acidity determination of 1 afforded ΔH°acid = 389.1 ± 0.8 kcal mol-1, and isotopic labeling established that the α-position of the three-membered ring is the favored deprotonation site. Interestingly, the structure of the base proved to be a key factor in correctly determining the proper ionization site (i.e., secondary amide ions are needed, and primary ones and OH- lead to incorrect conclusions since they scramble the deuterium label). An experimental measurement of the electron affinity of 1-phenylcyclopropyl radical (EA = 17.5 ± 2.8 kcal mol-1) was combined with the ionization energy of hydrogen (313.6 kcal mol-1) to afford BDE = 93.0 ± 2.9 kcal mol-1. This enabled the effect of the phenyl substituent to be evaluated and compared to other situations where it is attached to an sp³- or sp²-hybridized carbon center. M06-2X, CCSD(T), G4, and W1BD computations were also carried out, and a revised C-H BDE for cyclopropane of 108.9 ± 1.0 kcal mol-1 is recommended. [ABSTRACT FROM AUTHOR]

The interactions between five amino acid based anions([AA]−(AA = Gly, Phe, His, Try, and Tyr)) and N7,N9-dimethylguaniniumcation ([dMG]+) have been investigated by the hybrid densityfunctional theory method B3LYP together with the basis set 6-311++G(d,p).The calculated interaction energy was found to decrease in magnitudewith increasing side-chain length in the amino acid anion. The interactionbetween the [dMG]+cation and [AA]−anionin the most stable configurations of ion pairs is a hydrogen bondinginteraction. These hydrogen bonds (H bonds) were analyzed by the quantumtheory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analysis. Finally, several correlations between electron densities inbond critical points of hydrogen bonds and interaction energy as wellas vibrational frequencies in the most stable configurations of ionpairs have been checked. [ABSTRACT FROM AUTHOR]

Bridgehead C-H bond dissociation enthalpies of 105.7 ± 2.0, 102.9 ± 1.7, and 102.4 7plusmn; 1.9 kcal mol-1 for bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane, and adamantane, respectively, were determined in the gas phase by making use of a thermodynamic cycle (i.e., BDE(R-H) = ΔHºacid(H-X) - IE(H) + EA(X)). These results are in good accord with high-level G3 theory calculations and the experimental values along with G3 predictions for bicyclo[1.1.1]pentane, bicyclo[2.2.1]hexane, bicyclo[3.1.1]heptane, and bicyclo[4.2.1]nonane the gas found to correlate with the flexibility of the ring system. Rare examples of alkyl anions in the gas phase are also provided. [ABSTRACT FROM AUTHOR]

B3LYP/aug-cc-pVDZ computations were carried out on polyamines with up to seven amino groups. The gas-phase proton affinities of these compounds are 219.6 (1-BuNH2), 238.6 (H2NCH2CH2CH2CH2NH2), 252.8 [(H2NCH2CH2CH2)2CHNH2], 261.3 [(H2NCH2CH2CH2)3CNH2 (1)], and 288.5 kcal mol-1 [(H2NCH2CH2CH(NH2)CH2CH2)3CNH2]. These results indicate that the tetraamine is near the top of the basicity scale and the heptaamine is more basic than any neutral organic compound which has been measured to date. A gas-phase equilibrium acidity determination between 1 and DBU also was carried out, and PA(1) = 256.2 ± 2.1 kcal mol-1 was obtained. This demonstrates that multiple intramolecular hydrogen bonds can greatly increase basicities, and represents a new motif for designing super bases. [ABSTRACT FROM AUTHOR]

Like-charge ion pairing is commonly observed in protein structures and plays a significant role in biochemical processes. Density functional calculations combined with the conductor-like polarizable continuum model were employed to study the formation possibilities of doubly charged noncovalently linked complexes of a series of model compounds and amino acids in the gas phase and in solution. Hydrogen bond interactions were found to offset the Coulombic repulsion such that cation-cation clusters are minima on the potential energy surfaces and neither counterions nor solvent molecules are needed to hold them together. In the gas phase the dissociation energies are exothermic, and the separation barriers span from 1.7 to 15.6 kcal mol(-1). Liquid-phase computations indicate that the separation enthalpies of the cation-cation complexes become endothermic in water and nonpolar solvents with dielectric constants of ≥7 (i.e., the value for THF). These results reveal that electrostatically defying noncovalent complexes of like-charged ions can overcome their Coulombic repulsion even in low-polarity environments.

Understanding the nature of the interaction between metal nanoparticles and biomolecules has been important in the development and design of sensors. In this paper, structural, electronic, and bonding properties of the neutral and anionic forms of glutathione tripeptide (GSH) complexes with a Au(3) cluster were studied using the DFT-B3LYP with 6-31+G**-LANL2DZ mixed basis set. Binding of glutathione with the gold cluster is governed by two different kinds of interactions: Au-X (X = N, O, and S) anchoring bond and Au···H-X nonconventional hydrogen bonding. The influence of the intramolecular hydrogen bonding of glutathione on the interaction of this peptide with the gold cluster has been investigated. To gain insight on the role of intramolecular hydrogen bonding on Au-GSH interaction, we compared interaction energies of Au-GSH complexes with those of cystein and glycine components. Our results demonstrated that, in spite of the ability of cystein to form highly stable metal-sulfide interaction, complexation behavior of glutathione is governed by its intramolecular backbone hydrogen bonding. The quantum theory of atom in molecule (QTAIM) and natural bond orbital analysis (NBO) have also been applied to interpret the nature of interactions in Au-GSH complexes. Finally, conformational flexibility of glutathione during complexation with the Au(3) cluster was investigated by means of monitoring Ramachandran angles.