The synthesis of an efficient energy donor–acceptor system is reported, together with its photophysical properties. The bichromophoric species has been conceived to show potentialities for biological applications since a biocompatible disaccharide spacer, constituted of D-galactose and D-glucose derivatives, was used in compound 12 to connect two BODIPY units with different absorption/emission properties. The luminescence spectrum in acetonitrile of 12 shows an intense fluorescence band with a maximum at about 770 nm that is almost identical to that of the lowest-energy BODIPY, regardless of the excitation wavelength used. The quantum yield is 0.2 with an excited state lifetime of 2.5 ns. Excitation and ultrafast transient absorption spectroscopy demonstrates that a very efficient energy transfer takes place in 12 from the highest-energy lying BODIPY subunit to the lowest-energy emissive BODIPY moiety, with a time constant of about 31 ps. Noteworthily, the emission of 12 falls in the near infrared window, suitable for potential biological applications.

中文翻译：

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具有双糖间隔基的双发色体系的合成和光物理性质

报道了一种有效的能量供体-受体系统的合成及其光物理性质。由于在化合物12中使用了由D-半乳糖和D-葡萄糖衍生物构成的生物相容性二糖间隔基来连接具有不同吸收/发射性质的两个BODIPY单元，因此已经将双发色物种显示为具有生物应用潜力。乙腈中的发光光谱为12不管使用哪种激发波长，均显示出一个强的荧光带，在大约770 nm处有一个最大值，与最低能量的BODIPY几乎相同。量子产率为0.2，激发态寿命为2.5 ns。激发和超快速瞬态吸收光谱表明，在12能量中，能量分布最高的BODIPY亚基到能量最低的发射BODIPY部分发生了非常有效的能量转移，其时间常数约为31 ps。值得注意的是，12的发射落在近红外窗口中，适合潜在的生物应用。