levogyrní

Levogyrní is a term used to describe a property of substances or phenomena that rotate plane-polarized light in a counter-clockwise direction. This phenomenon is known as levorotation. Substances that exhibit levorotation are called levorotatory or levogyrous. This optical activity is a characteristic of chiral molecules, which are molecules that are non-superimposable on their mirror images.

The extent of rotation is measured using a polarimeter, and the specific rotation is a standardized value that accounts for concentration, path length, and temperature. Levorotation is often denoted by a minus sign (-) or the prefix 'l-' or 'levo-'. For example, levorotatory forms of tartaric acid are designated as l-(+)-tartaric acid, indicating that while the acid itself is levorotatory, its stereochemical configuration is designated as D according to the older convention.

Many biologically important molecules, such as L-amino acids and D-sugars (which are levorotatory when referred to by their specific rotation, despite the naming convention), are chiral and exhibit optical activity. The direction of rotation is an intrinsic property of the molecule's three-dimensional structure and is independent of its chemical reactivity. Understanding levorotation is crucial in fields such as organic chemistry, biochemistry, and pharmacology, as the biological activity of enantiomers (mirror-image isomers) can differ significantly.