反应详情

A sodium 2-thiophenecarboxylate aqueous solution was obtained by dissolving 1.64 g of sodium hydroxide in 300 ml of purified water and then under stirring, adding 5.25 g of 2-thiophenecarboxylic acid (purity 99%; conjugate number=3) in the resultant aqueous solution until thorough solution. Then, a europium chloride aqueous solution obtained by thoroughly dissolving 5.0 g of europium chloride (EuCl3.6H2O; purity 99.99%) in 50 ml of purified water was gradually added while under stirring to the aforementioned sodium 2-thiophenecarboxylate aqueous solution at room temperature. The resultant reaction solution was adjusted to pH 5.0 with 0.1 N hydrochloric acid and then stirred thoroughly. Subsequently, the aqueous solution was evaporated to afford europium 2-thiophenecarboxylate ##STR6## The europium 2-thiophenecarboxylate thus obtained was dried in vacuo at 80° to 100° C. for 20 to 24 hours. This salt had its maximum excitation wavelength at about 340 nm and strongly showed the red luminescence peculiar to europium at the main emission wavelength of about 616 nm. The luminescence efficiency was 31%. When it was tested for X-ray powder diffraction and DSC, it showed crystalline diffraction pattern and endothermic peaks.

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