Search

Covalent functionalization of cellulose with β‐cyclodextrin by succinic acid‐promoted cross‐linking leads to a dual‐function material that efficiently promotes proximity‐induced energy transfer from polycyclic aromatic hydrocarbons (PAHs) to squaraine fluorophores with high quantum yields, and removes PAHs from aqueous solution through non‐covalent binding. This material, which possesses a high functionalization density (0.17 μg/mm2 of cyclodextrin on cellulose), promotes energy transfer efficiencies as high as 58 % (for an anthracene donor in combination with a squaraine fluorophore acceptor), and leads to the removal of up to 91 % of a PAH (pyrene) from aqueous solution by mixing of the solution with the functionalized material. Overall, the high performance of this material in both proximity‐induced energy transfer and the removal of PAHs from water means that such a method has significant potential impact in a variety of real‐world environmental remediation scenarios. [ABSTRACT FROM AUTHOR]

Reported herein is the synthesis and application of three novel β‐cyclodextrin dimer hosts for the complexation of near infrared (NIR) squaraine dyes in aqueous solution. A series of eight different N‐substituted N‐methyl anilino squaraine dyes with variable terminal groups are investigated, with an optimal n‐hexyl‐substituted squaraine guest demonstrating binding constants orders of magnitude higher than the other squaraine–host combinations and comparable to literature‐reported systems. Moreover, hydrophobic complexation of the squaraine dyes with the β‐cyclodextrin dimer hosts causes drastic changes in the squaraine's photophysical properties, propensity for aggregation and susceptibility to hydrolytic decay. [ABSTRACT FROM AUTHOR]

A second, monoclinic, polymorph of the title compound, C14H8Cl2, has been found. In addition to the structure of this monoclinic form, the structure of the previously described orthorhombic form [Desvergne, Chekpo & Bouas-Laurent (1978). J. Chem. Soc. Perkin Trans. 2, pp. 84-87; Benites, Maverick & Fronczek (1996). Acta Cryst. C 52, 647-648] has been redetermined at low temperature and using modern methods. The low-temperature structure of the orthorhombic form is of significantly higher quality than the previously published structure and additional details can be derived. A comparison of the crystal packing of the two forms with a focus on weak intermolecular C-H...Cl interactions shows the monoclinic structure to have one such interaction linking the molecules into infinite ribbons, while two crystallographically independent C-H...Cl interactions give rise to an interesting infinite three-dimensional network in the orthorhombic crystal form. [ABSTRACT FROM AUTHOR]