Incorporation of Rare-Earth Complex Eu(TTA)₄C₅H₅NC₁₆H₃₃ into Surface-Modified Si−MCM-41 and Its Photophysical Properties

Abstract

The incorporation of the rare-earth complex [C 5 H 5 NC 16 H 33 ][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 (C 2 H 5 O) 3 Si(CH 2 ) 2 NH(CH 2 ) 2 NH 2 (NSED), (C 2 H 5 O) 3 Si(CH 2 ) 3 NH 2 (APTES), and (C 2 H 5 O) 3 Si(CH 2 ) 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 [C 5 H 5 NC 16 H 33 ][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 5 D 0 -7 F 2 . This phenomenon is rarely seen in the luminescence of rare-earth complexes. The UV stability and lifetime of Eu 3+ 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.

Novel luminescent europium(III) complexes covalently bonded to bis(phosphino)amine oxide functionalized MCM-41

“…The blue shift confirms that the rare-earth complex is incorporated into the MCM-41 channels, which influences its corresponding absorption. A similar phenomenon was also observed for the other modified MCM-41 materials [18]. In general, UV-Vis and IR spectra indicate that the Eu 3+ is present in the coordinated form covalently bond to the MCM-41 network.…”

Photonic and nanobiophotonic properties of luminescent lanthanide-doped hybrid organic–inorganic materials

“…For instance, the entrapment of lanthanide complexes into surface-modified mesoporous silica (MCM41, MCM48 and SBA15) by a two-step procedure has been widely studied. [86][87][88][89][90][91][92] In general, a lanthanide complex interacts with its surrounding silylating agents through weak hydrogen-bonding interactions, and optical processes (emission intensity, wavelength and lifetime) can be modulated depending on the lanthanide coordination.…”

Synthesis and luminescence properties of SBA-15 functionalized with covalently bonded ternary europium complex

“…The ordered mesoporous silica materials with the good rigidity and photostability would provide a well-defined hydrophilic/hydrophobic phase separation for adjusting the lanthanide microenvironment [6]. The encapsulation of rare earth complexes into mesostructured materials has been described in recent studies and an enhanced emission was observed [7][8][9]. Usually, such materials are obtained by doping mesoporous silica materials with lanthanide complexes, in which only weak physical interactions exist between the mesoporous silica materials and the complexes.…”