نتایج جستجو برای: halogen
تعداد نتایج: 4763 فیلتر نتایج به سال:
background: one of the first‑line assessment tools for fetal surveillance is nonstress test (nst), although it is limited by a high rate of false‑nonreactive results. this study was performed to investigate if external stimulation from vibroacoustic and halogen light could help in provoking fetal responsiveness and altering nst results. materials and methods: this is a clinical trial. sampling ...
There has recently been an increasing interest in controlling macromolecular conformations and interactions through halogen bonding. Halogen bonds are favorable electrostatic interactions between polarized, electropositive chlorine, bromine, or iodine atoms and electronegative atoms such as oxygen or nitrogen. These interactions have been likened to hydrogen bonds in terms of their favored acce...
The calculated properties of substituted carboranes such as dipole moment, polarisability, the magnitude of the σ-hole and the desolvation free energy are compared with these properties in comparable aromatic and cyclic aliphatic organic compounds. Dispersion and charge transfer energies are similar. However, the predicted strength of the halogen bonds with the same electron donor (based on the...
Trends in the properties of normal valent and multivalent halogen-oxygen bonding are examined for the isomers of the halogen polyoxide families of the types (YXO2) and (YXO3), Y = Cl, Br, I, H, CH(3), X = Cl, Br, I. A qualitative model is formulated on the relationship between the X-O bond distance variations, the ionic character of the bonding, and the degree of halogen valence. The relative s...
Background and Aim: Halogen lamp is the commonly used light source for composite photo polymerization. Recently, high power halogen lamps, LED and plasma arc are introduced for improving the polymerization. The aim of this study was to investigate the effect of conventional and high power halogen lamps and LED light curing unit on degree of conversion of two different composite resins.Materials...
In the present study we have characterized the halogen bonding in selected molecules H3N-ICF3 (1-NH 3 ), (PH3)2C-ICF3 (1-CPH 3 ), C3H7Br-(IN2H2C3)2C6H4 (2-Br), H2-(IN2H2C3)2C6H4 (2-H 2 ) and Cl-(IC6F5)2C7H10N2O5 (3-Cl), containing from one halogen bond (1-NH 3 , 1-CPH 3 ) up to four connections in 3-Cl (the two Cl-HN and two Cl-I), based on recently proposed ETS-NOCV analysis. It was found base...
The structure of the title compound, (C(24)H(20)P)(2)[Te(2)I(6)], is composed of discrete PPh(4) (+) cations and centrosymmetric [Te(2)I(6)](2-) anions. The tellurium(II) atom shows a sligthly distorted square-planar TeI(4) geometry and is coordinated to two bridging and two terminal iodine atoms. The planar [Te(2)I(6)](2-) ions are isolated by the cations and no inter-molecular tellurium-halog...
Halogen bonds mediated by iodine (Z = 53) can be more affected relativistic effects than halogen astatine 85).
MP2/aug'-cc-pVTZ calculations have been carried out to investigate the halogen-bonded complexes formed when CO and CS act as electron-pair donors through C to ClF, ClNC, ClCl, ClOH, ClCN, ClCCH, and ClNH₂. CO forms only complexes stabilized by traditional halogen bonds, and all ClY molecules form traditional halogen-bonded complexes with SC, except ClF which forms only an ion-pair complex. Ion-...
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