Cooperative sol–gel assembly, characterization and photoluminescence of rare earth hybrids with novel dihydroxyl linkages and 1,10-phenanthroline

A novel series of photoactive binary and ternary rare earth (Eu3+, Tb3+) hybrids with organic parts covalently bonded to inorganic parts via hydroxyl linkage and 1,10-phenanthroline (Phen) have been cooperative assembled through a sol–gel process. Two molecular bridges are used as covalent linkage from the functionalization of 4-vinylbenzeneboronic acid (VBBA) by two different silane crosslinking reagents (3-chloropropyl-trimethoxysilane (CPTMS) and 3-aminopropyltriethoxysilane (APTES)) after the copolymerization with acrylic acid, which mainly behave as structural unit to form the Si–O network. Besides, Phen is fabricated as the assistant functional ligand to sensitize the luminescence of rare earth ions. These hybrids are characterized and especially photophysical properties of them are studied in detail. Compared to binary hybrid materials RE–VC and RE–VA (RE = rare earth; VC = VBBA–CPTMS linkage; VA = VBBA–APTES linkage), ternary hybrid materials Phen–RE–VC and Phen–RE–VA exhibit stronger luminescence intensity, longer lifetime and higher quantum efficiency, proving that introduction of Phen improves luminescence of rare earth ions within hybrid system.

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► Novel linkages of functionalized 4-vinylbenzeneboronic acid.
► New rare earth hybrids.
► Luminescence in visible region.
► Cooperative sol–gel assembly.