Deshielding—The phenomenon of atoms pulling electron density away from surrounding atoms; in
NMR spectroscopy, pulls a group further downfield on the spectrum.
Developing chamber—A beaker with a lid or wide-mouthed jar used in thin-layer chromatography.
Dialcohols—Alcohols with two hydroxyl groups that are commonly used as protecting groups for
aldehyde or ketone carbonyls; also called diols.
Diastereomers—Non-mirror-image configurational isomers that differ at at least one—but not all—
chiral carbons; have different chemical and physical properties.
Distillate—The liquid evaporated, condensed, and collected during distillation.
Distillation—A separation and purification technique that takes advantage of differences in boiling
point to separate two liquids by vaporization and condensation.
Doublet—Two peaks of identical intensity in an NMR spectrum that are equally spaced around the
true chemical shift of a group of protons; results from splitting by another hydrogen.
Downfield—Movement toward the left in an NMR spectrum.
Electron-donating—Describes groups that push additional electron density toward another atom;
stabilizes positive charges and destabilizes negative charges while decreasing acidity.
Electron-withdrawing—Describes groups that pull electron density away from another atom;
stabilizes negative charges and destabilizes positive charges while increasing acidity.
Electrophile—“Electron-loving” atoms with a positive charge or positive polarization that can
accept an electron pair when forming new bonds with a nucleophile.
Eluent—The solvent used in chromatography, after it has passed through the stationary phase.
Elute—To displace with solvent, as in thin-layer chromatography.
Enantiomers—Nonsuperimposable mirror images of a chiral molecule; have all the same physical
and chemical properties except for rotation of plane-polarized light and reactions in a chiral