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Absorption spectrum of an aqueous solution of potassium permanganate, showing a vibronic fine structure in the LMCT band. The tetraoxides of d 0 metal centers are often deeply colored for the first row metals. This coloration is assigned to LMCT, involving transfer of nonbonding electrons on the oxo ligands to empty d-levels on the metal.
In chemistry, charge-transfer (CT) complex, or electron donor-acceptor complex, describes a type of supramolecular assembly of two or more molecules or ions. The assembly consists of two molecules that self-attract through electrostatic forces, i.e., one has at least partial negative charge and the partner has partial positive charge, referred ...
For example, the colour of chromate, dichromate and permanganate ions is due to LMCT transitions. Another example is that mercuric iodide , HgI 2 , is red because of a LMCT transition. A metal-to-ligand charge transfer (MLCT) transition will be most likely when the metal is in a low oxidation state and the ligand is easily reduced.
Absorption spectrum of an aqueous solution of potassium permanganate. As an example from inorganic chemistry the permanganate ion, MnO − 4, in aqueous solution has an intense purple colour due to an O → Mn ligand-to-metal charge transfer band (LMCT) in much of the visible region. [22]
Protein folding problem: Is it possible to predict the secondary, tertiary and quaternary structure of a polypeptide sequence based solely on the sequence and environmental information? Inverse protein-folding problem: Is it possible to design a polypeptide sequence which will adopt a given structure under certain environmental conditions?
Compounds that obey the 18-electron rule are typically "exchange inert". Examples include [Co(NH 3) 6]Cl 3, Mo(CO) 6, and [Fe(CN) 6] 4−.In such cases, in general ligand exchange occurs via dissociative substitution mechanisms, wherein the rate of reaction is determined by the rate of dissociation of a ligand.
Typical examples of building block collections for medicinal chemistry are libraries of fluorine-containing building blocks. [ 24 ] [ 25 ] Introduction of the fluorine into a molecule has been shown to be beneficial for its pharmacokinetic and pharmacodynamic properties, therefore, the fluorine-substituted building blocks in drug design ...
For example, using 18-crown-6, potassium acetate is a more powerful nucleophile in organic solvents: [1] [K·(18-crown-6)] + AcO − + C 6 H 5 CH 2 Cl → C 6 H 5 CH 2 OAc + [K·(18-crown-6)] + Cl −. The first electride salt to be examined with X-ray crystallography, [Cs(18-crown-6) 2] + ·e −, was synthesized in 1983. This highly air- and ...