Incorporation of rare-earth complex Eu(TTA)4C5H5NC16H33 into surface-modified Si-MCM-41 and its photophysical properties

The incorporation of the rare-earth complex [C5H5NC16H33] [Eu(TTA)(4)] into surface-modified mesoporous molecular sieve Si-MCM-41 via reactions of the surface Si-OH with different silylation agents such as (C2H5O)(3)Si(CH2)(2)NH(CH2)(2)NH2 (NSED), (C2H5O)(3)Si(CH2)(3)NH2 (APTES), and (C2H5O)(3)Si(CH2)(3)CN (TSBT) and their photophysical properties were studied. The results show that the surface silylation of Si-MCM-41 provides a unique chemical environment for the incorporated [C5H5NC16H33] [Eu(TTA)(4)] complex. Hydrogen-bonding interactions of the rare-earth complex with its surrounding silylating agents alter the photophysical properties of the rare-earth complex. The emission intensity and color purity of the excited rare-earth complex in these surface-silylated Si-MCM-41 materials increase in the order of Si-MCM-41 < TBST-Si-MCM-41 < APTES-Si-MCM-41 < NSED-Si-MCM-41. Because of the strongest hydrogen bonding in NSED-Si-MCM-41, the rare-earth complex only emits light with a single wavelength, corresponding to D-5(0)-F-7(2). This phenomenon is rarely seen in the luminescence of rare-earth complexes. The UV stability and lifetime of Eu3+ in the rare-earth complex were also studied, and the results show that the incorporated rare-earth complex exhibits higher UV stability and increased lifetime compared to the pure rare-earth complex.