No abstract

The one- and two-photon luminescence of stilbene-type solid-state materials can be tuned and controlled from blue to yellow color by a supramolecular cocrystal method.

Monohydroxylated cucurbit[6]uril was prepared for the first time through the controlled oxidation of CB[6] in the presence of a tailor-made bisimidazolium guest, as verified by (1)H NMR, ESI-MS and X-ray crystallography. Further chemical modification of monohydroxylated CB[6] was also readily achieved.

Herein we report the photocontrol of cucurbit[8]uril (CB[8])-mediated supramolecular polymerization of azobenzene-containing monomers. The CB[8] polymers were characterized both in solution and in the solid state. These host-guest complexes can be reversibly switched between highly thermostable photostationary states. Moreover, a remarkable stabilization of Z-azobenzene was achieved by CB[8] complexation, allowing for structural characterization in the solid state.

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Gel media have been utilized for over a century for the growth of inorganic, organic and protein crystals. [1][2][3][4][5] The improved physical characteristics of the resulting crystals (better optical quality, larger size and fewer defects) are usually ascribed to the suppression of convection currents, sedimentation and nucleation afforded by the viscous gel environment. [6][7] In many instances the gel is thought to act as an inert matrix within which crystal growth occurs, however in some cases, the gel structure has been shown to influence the polymorphism, enantiomorphism and habit of crystals. 2 Occasionally gel fibres may become incorporated into the crystal, giving rise to composite materials. 8Conventional gels are formed using polymeric or clay-like materials such as gelatine, solubility were investigated to demonstrate their potential to act as crystallisation media for molecular organic compounds. Compounds 2, and 4 have been reported previously. [23][24] Novel compounds 1 and 3 were prepared by standard methods as detailed in the supplementary information. Gelators 1 -3 were chosen because they reliably form gels in a number of solvents ranging from aqueous systems to toluene. The fibrous nature of the gels is evidenced by SEM images of the dried xerogels ( Figure 1a,b). Compound 4 is a metallogelator which forms blue coloured gels with substoichiometric amounts of CuCl 2 in methanol:water. 23 Between them, these gelators can gel a range of solvents, at different temperatures (T gel ), and with a different critical gelator concentration (CGC). This class of compound has the potential to form the basis of a library of gelators which will allow the selection of gel properties and specific functionalities to match the compound and crystallisation conditions of interest. The synthetic versatility of these gelators could also in principle allow the incorporation of tailored heteronucleating functionality. While we focus upon bis(urea) compounds, the concepts outlined herein equally apply to any LMWG.Crystallisation experiments were undertaken using a range of organic compounds of both drug and non-drug species in parallel in both gel and solution media. We undertook an initial screen using candidate compounds 2-hydroxy benzyl alcohol (HBA, 5), Aspirin (ASP, 6), carbamazepine (CBZ, 7), 1-(3-methylsulfanyl-phenyl)-3-pyridin-2-yl-urea (SPU, 8) and 1,3-bis(m-nitrophenyl)urea (NPU, 9). We then carried out a detailed study on CBZwith all gelators, and a follow up study on gelator ...