title: Preorganizing linear (self-complementary) quadruple hydrogen-bonding arrays using intramolecular hydrogen bonding as the sole force.
abstract: [structures: see text] In this article we describe a rational approach for prefixing multiple cooperative binding sites in an ideal spatial arrangement on a structurally rigid backbone, constrained exclusively by intramolecular hydrogen bonding. The idea is exemplified by the ability of the self-assembling constructs 1a-e and 2a,b to form hydrogen-bonded dimers, whose structural preorganization has been solely effected by intramolecular hydrogen bonding. The readily accessible amidinourea backbone has been used as a common platform for the construction of a variety of such self-assembling systems. ESI mass spectrometry and single-crystal X-ray diffraction studies have been particularly effective in investigating the self-assembling propensities of these systems. Remarkably, most the H-bonded dimers reported herein undergo an unusual mode of self-assembly, using intermolecular four-membered ring hydrogen-bonded interaction, affording extended supramolecular networks.
authors.affiliation: Division of Organic Synthesis and Center for Materials Characterization, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
authors.forename: Panchami
authors.initials: P
authors.lastname: Prabhakaran
authors.forename: Vedavati G
authors.initials: VG
authors.lastname: Puranik
authors.forename: Gangadhar J
authors.initials: GJ
authors.lastname: Sanjayan