Three Types of Lanthanide-Containing Polyoxoniobates and Their Luminescence Properties.

Fourteen lanthanide (Ln)-containing hetero selenato-phosphato-peroxopolyoxoniobates in three series: (1) Cs 2 {[Ln(H 2 O) 4 ][H 4 P 2 Se 2 Nb 6 (O 2 ) 6 O 22 ]} 2 · n H 2 O [Ln = Ce ( I-Ce ), Pr ( I-Pr ), Sm ( I-Sm ), Eu ( I-Eu ), Gd ( I-Gd ); I-Ce , I-Pr , I-Eu , I-Gd n = 12; I-Sm n = 16]; (2) Cs 2 K 3 {[Ln(H 2 O) 6 ][H 2.5 P 2 Se 2 Nb 6 (O 2 ) 6 O 22 ]} 2 · n H 2 O [Ln = Dy ( II-Dy ), Tm ( II-Tm ), Yb ( II-Yb ), Lu ( II-Lu ); II-Dy n = 14; II-Tm n = 24; II-Yb , II-Lu n = 13]; (3) Cs 5 K 2 H m {[Ln(H 2 O) 6 ][P 2 Se 2 Nb 6 (O 2 ) 6 O 22 ]} 2 {[Ln x (H 2 O) y ] 2 [P 2 Se 2 Nb 6 (O 2 ) 6 O 22 ]}· n H 2 O [Ln = Ho ( III-Ho ), Er ( III-Er ), Tm ( III-Tm ), Yb ( III-Yb ), Lu ( III-Lu ), III-Ho-III-Yb m = 5, x = 1; y = 5; III-Lu m = 6.5; x = 0.75; y = 4; III-Ho-III-Tm n = 19, III-Yb n = 34; III-Lu n = 31], have been isolated by a one-pot reaction and structurally characterized by various physical and chemical analyses. These compounds represent the first group of Ln-functionalized polyoxoniobates with mixed heteroatoms. In addition, the photoluminescence properties of compounds I-Sm , I-Eu , and II-Dy were measured, and the time-resolved emission spectra showed that the {P 2 Se 2 Nb 6 } segment contributed to the energy transfer from the polyoxoniobate units to the Ln 3+ center, which effectively promoted the emission of the Ln 3+ center.