Templated crystal nucleation: mixed crystals of very different copper(ii) N,N′,N″-trimethyltriazacyclononane complexes

Abstract

Templation of a daughter phase by a parent crystal results from an equilibrating mixture of two very different copper(ii) N,N',N''-trimethyltriazacyclononane complexes.

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

“…26 These gorgeous patterns arise from the periodic precipitation of a weakly soluble salt such as silver chromate as a soluble precursor 15 such as silver nitrate diffuses through a hydrogel containing potassium chromate, Figure 6. In this case the gel is pre-formed before the crystallization process begins but in other cases both the gel and crystal formation start from a homogeneous solution into which both gelator and crystallization substrate are both 20 dissolved. 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.…”

“…The fact that a very wide range of simple LMWG can be readily synthesised means that their structure can be readily adapted to tune their solubility allowing access to a huge range of organogels as crystallization media. In general, while there are a few reports of 20 crystallization from non-aqueous media such as the crystallization of 1:1 complexes of quinones with hydroquinones out of Sephadex LH.20 (an alkylated cross-linked dextran) or the crystallization of silver bromide from polyvinyl chloride in dimethyl sulfoxide, 36 organogels are highly under-utilised as 25 crystal growth media. LMWG also offer the potential to synthesise gelators that match the chemical structure of the crystallization substrate and hence provide an active nucleation surface.…”

“…These activated building blocks are hydrolysed over time to guanosine diphosphate tubulin resulting in microtubule collapse. The assembly thus requires constant renewal and hence exhibits 20 interesting properties such as self-healing. 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.…”

“…The two orthogonal materials may be physically entangled in longer length scales. 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.…”

Di-μ-chlorido-bis[chlorido(1,4,6-trimethyl-6-nitro-1,4-diazepine)copper(II)]

“…For the synthesis of the meaaz-NO 2 ligand see Ge et al (2006). For related structures, see: Astner et al (2008); Schwindinger et al (1980); Steed et al (2007).…”