Preorganizing Linear (Self-Complementary) Quadruple Hydrogen-Bonding Arrays Using Intramolecular Hydrogen Bonding as the Sole Force

摘要

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 la-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 su-pramolecular networks.