A charge density study of an intramolecular charge-transfer quinoid compound with strong NLO properties

An experimental charge density investigation of 7,7-di[(S)-(+)-2-(methoxymethyl)pyrrolidino]-8,8-dicyanoquinodimethane establishes the presence of a large charge separation as well as a high in-crystal dipole moment compared to the free molecule in frozen geometry, consistent with the high SHG activity of the compound.