Molecular recognition directed self-assembly of ordered supramolecular strands by cocrystallization of complementary molecular components

Supramolecular gel phase crystallization: orthogonal self-assembly under non-equilibrium conditions

“…The nucleation of each component may be primary, secondary or follow a non-classical two-step mechanism, 10 and crucially the presence of more than 20 one component offers the opportunity for each of the two orthogonal assembly processes to influence the outcome of the other one. However, solubility constraints and kinetic factors mean that each process may not occur at the same rate and hence there is the possibility of temporal as well as spatial separation of 25 the individual assemblies. Examples of such uncoupled processes have been demonstrated in gelation by Smith who showed that independent assembly of a mixture of two different gelators can give rise to two independent, non-interacting networks described as 'multi-gelator' gels.…”

“…7 Recently, an artificial dissipative self-assembled supramolecular gel phase material has been reported by the van Esch group based on the methyl iodide consuming esterification of the non-gelating anionic form of dibenzoyl-(L)-cystine. 8 Ester formation converts the compound to 25 an effective hydrogelator, however under basic conditions the gelator is continually hydrolysed requiring constant, energy dissipating input of MeI. An interesting example of non-equilibrium self-assembly is the crystallization (and gelation) process.…”

“…24 These examples build on earlier work on aminopyrimidine/dialkylbarbituric acid mixtures. 25 Nonstoichiometric multicomponent gel blends based on different amino acid derivatives of bis(urea) gelators are currently under exploration by our own group in which the gelation and sol 15 formation can be probed by fluorescent reporter groups blended with the principal gelator. …”

“…A review on the early work on gel crystallization was published as long ago as 1917, 27 but it was not until the 1970's that the search for semiconducting and laser active materials prompted a surge in interest in the technique, summarised in a 1976 book on the topic by Henisch. 28 Gel phase crystallization 25 represents a prime de facto example of orthogonal self-assembly of the crystals and gel network, which are generally microphase separated and retain a distinct identity, although in some cases the gel influences the outcome of the (generally slower) crystallization process. Formation of crystalline minerals, or 30 protein crystals from aqueous silica gel or organic biogels such as agar or gelatin is a commonly used contemporary technique often resulting in higher quality, larger crystals suitable for protein crystallography, as shown in Figure 7.…”

Ditopic receptors capable of hydrogen bonding: Synthesis and complexation behaviour of diaza crown-ethers having melamine sidearms

“…The reaction mixture was allowed to cool to RT and filtered through Celite; the precipitate was carefully washed with 30 mi of DMF and the filtrates were evaporated to dryness under reduced pressure. The residue was taken up in Et20 to give, after filtration, 0.57 g ( (6). Solid Na2CO3 (8.9 g, 83.8 mmol) was added to a solution of N2-18-C-6 (1.22 g, 4.66 mmol) and the phthalimido derivative 5 (2.50 g, 9.32 mmol) in 100 ml of CH3CN and the resulting suspension was stirred at 80 °C for 48h.…”