Search results
Results from the WOW.Com Content Network
Formal charges in ozone and the nitrate anion. In chemistry, a formal charge (F.C. or q*), in the covalent view of chemical bonding, is the hypothetical charge assigned to an atom in a molecule, assuming that electrons in all chemical bonds are shared equally between atoms, regardless of relative electronegativity.
The alkene ligand in these cations is activated toward attack by nucleophiles, opening the way to a number of carbon–carbon bond-forming reactions. Nucleophilic additions usually occur at the more substituted carbon. This regiochemistry is attributed to the greater positive charge density at this position.
In coordination chemistry, a bridging ligand is a ligand that connects two or more atoms, usually metal ions. [1] The ligand may be atomic or polyatomic. Virtually all complex organic compounds can serve as bridging ligands, so the term is usually restricted to small ligands such as pseudohalides or to ligands that are specifically designed to ...
Both oxygen atoms equally share the negative charge. The acetylacetonate anion is a bidentate ligand. IUPAC recommended pK a values for this equilibrium in aqueous solution at 25 °C are 8.99 ± 0.04 (I = 0), 8.83 ± 0.02 (I = 0.1 M NaClO 4) and 9.00 ± 0.03 (I = 1.0 M NaClO 4; I = Ionic strength). [9] Values for mixed solvents are available.
All 5 carbon atoms of a Cp ligand are bound to the metal in the vast majority of M–Cp complexes. This bonding mode is called η 5-coordination. The M–Cp bonding arises from overlap of the five π molecular orbitals of the Cp ligand with the s, p, and d orbitals on the metal. These complexes are referred to as π-complexes.
Instead of simply assigning a charge (oxidation state) to an atom in the molecule, the covalent bond classification method analyzes the nature of the ligands surrounding the atom of interest. [2] According to this method, the interactions that allow for coordination of the ligand can be classified according to whether it donates two, one, or ...
Ligand efficiency is a measurement of the binding energy per atom of a ligand to its binding partner, such as a receptor or enzyme. [ 1 ] Ligand efficiency is used in drug discovery research programs to assist in narrowing focus to lead compounds with optimal combinations of physicochemical properties and pharmacological properties.
The associated Hückel Coulomb charge is defined as = (), where () is the number of π-electrons contributed by a neutral, sp 2-hybridized atom j (we always have = for carbon). For carbon 1 on benzene, this yields a π-electron population of