Research on Syntheses and Properties of Water-soluble SymmetricalSquarylium Double-cyanine Dyes

In this paper, 2,3,3-trimethyl-3H-indolin was synthesised by phenylhydrazine and 3-methyl-2-butanone as raw materials in the acetic acid, and then was reacted with different nitrogen lkylating reagents. The two kinds of conducts acted with squaric diethyl ester respectively to prepare mono-semicynine dye and dis-semicyanine dye. The spectral properties of the target products were checked. The results show that compared with symmetrical squarylium mono- indocyanine dyes with the same subtituent, the photo-stability of the bis-cyanine dyes were much better obviously.. When disssolved in water, the dye has the shortest maximum absorption wavelength, shortest maximum emission wavelength and shortes Stokes shift and obvious aggregation. In protic solvents, dye spectra show a blue shift with the increasing of solution polarity, while in aprotic solvents, dye spectral have a red shift with the increasing of solution polarity. Indifferent solvents, the photo-stability of the dye in methanol is strongest.