Design and Synthesis of a C₂-Symmetric Self-Complementary Hydrogen-Bonding Cleft Molecule Based on the Bicyclo[3.3.1]nonane and 4-Oxo-5-azaindole Framework. Formation of Channels and Inclusion Complexes in the Solid State

Abstract

The synthesis of a C2-symmetric cleft molecule 2 based on the fused framework between bicyclo[3.3.1]nonane and 4-oxo-5-azaindole, incorporating a self-complementary hydrogen-bonding motif, in both racemic and enantiomerically pure forms is reported. This cleft molecule is reminiscent of analogues of Tröger's base though with different cleft dimensions and tilt angles. The framework of 2 provides a building block for the construction of self-assembled hydrogen-bonded supramolecular structures. The solid-state structure of 2 is highly influenced by the limited solubility of (+/-)-2 and (-)-2. The solvents interact with the potential hydrogen-bonding motifs of (+/-)-2 and (-)-2, forming different three-dimensional structures as revealed by X-ray diffraction analysis. In the solid state (+/-)-(2)2 x 5DMF forms hydrogen-bonded pleated band structures that build up three-dimensional pens between adjacent bands in which two molecules of DMF are trapped. In contrast, the aggregate obtained from (-)-2, (-)-2 x 2AcOH, showed infinite bands of complex constitution.

Synthesis and Self‐Aggregation of Enantiopure and Racemic Molecular Tweezers Based on the Bicyclo[3.3.1]nonane Framework

“…[33] Within the field of supramolecular chemistry, 3 has been used to introduce chirality into crown ethers, [34,35] as a backbone in self-complimentary hydrogen-bonding cleft molecules, [36,37] and has served as lattice-inclusion hosts. [38,39] During the course of our investigations into the development of various supramolecular architectures, we herein report on the synthesis of an enantiomerically pure pair of molecular tweezers ((R,R,R,R)-4) from the enantiopure bicycloA C H T U N G T R E N N U N G [3.3.1]nonane framework containing a pyrazine tether and quinoline arms (Scheme 2) and their self-aggregating properties in solution.…”

Synthesis, Molecular Structure, and Chiroptical Properties of Dibenzylidene Derivatives of Bicyclo[3.3.1]nonane and Brexane

“…9 The chirality and molecular shape of the bicyclo[3.3.1]nonane framework has been proven to be particularly suitable for design of monomers with specific molecular shape and inherent geometric features responsible for controlled self-assembly of a wide range of supramolecular structures. [10][11][12] Among the methods currently available for structural studies, circular dichroism (CD) spectroscopy is a well-established technique for determination of the absolute configuration of chiral compounds. 13 A variety of methodologies, ranging from empirical rules to ab initio quantum mechanical methods, have been developed for the correlation of the absolute configuration with observed sign and magnitude of Cotton effects (CEs) in the CD spectra.…”

Synthesis of new heterocyclic systems containing the bicyclo-[3.3.1]nonane fragment

“…According to [2] Absorptions of carbonyl and imine groups were observed in the IR spectra of compounds 2-4. In the 1 H NMR spectra only multiplet, characteristic of the bicyclo[3.3.1]nonane fragment, and signals of the phenyl and amino group protons (3 and 4 respectively).…”