title: Two types of monoethyl alpha-anilinobenzylphosphonates: a zwitterion and a molecular compound.
abstract: The crystal structures of the potential antitumour agents monoethyl (alpha-anilinobenzyl)phosphonate, C(15)H(18)NO(3)P, (I), and its 4-azobenzene-substituted derivative monoethyl [alpha-[4-(phenyldiazenyl)anilino]benzyl]phosphonate, C(21)H(22)N(3)O(3)P, (II), are described. A zwitterionic form of (I) and a neutral molecular form of (II) are observed, which is fully in accordance with previously reported spectroscopic studies. In both structures, hydrogen bonding induces the formation of zigzag head-to-head double layers parallel to the crystallographic b axis.
authors.affiliation: Rudjer Bosković Institute, PO Box 180, HR-10002 Zagreb, Croatia. aleksandar.visnjevac@irb.hr
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Visnjevac
authors.forename: Ljerka
authors.initials: L
authors.lastname: Tusek-Bozić