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[摘要]：Organic Pigments, Fluorescent Brighteners, and Photographic A merocyanine dye equipped with a Hamilton-receptor unit has been synthesized that enables strong noncovalent binding of other merocyanine dyes bearing barbituric acid acceptor groups by six hydrogen bonds. NMR and UV/visible titrn. expts. in toluene, chloroform, dichloromethane, dioxane, and THF provide evidence for the formation of 1:1 complexes even in the dipolar solvents. An enhanced binding strength is obsd. for the more dipolar merocyanine dyes in the head-to-tail assembly structure with binding consts. up to >108 M-1 in toluene. In the present bimol. complexes two merocyanine chromophores are assembled in a head-to-tail fashion that affords increased dipole moments as demanded for efficient elec. field induced poling processes in nonlinear optical and photorefractive polymeric hosts. The solvent dependency of the binding consts. for various barbituric acid dye-Hamilton receptor complexes as well as a perylene imide-melamine complex reveals linear free energy relationships (LFER) that allow for an estn. of binding consts. larger than 1012 M-1 for Hamilton receptor organized head-to-tail merocyanine bimol. complexes in aliph. solvents. It is suggested that such LFER are valuable tools for the estn. of binding consts. in solvents where exptl. binding consts. cannot be detd. because of soly. or spectroscopic problems. |
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