Gas Sorption, Second-Order Nonlinear Optics, and Luminescence Properties of a Series of Lanthanide–Organic Frameworks Based on Nanosized Tris((4-carboxyl)phenylduryl)amine Ligand

By controlling the pH value of the
reaction system, two sets of
lanthanide (Ln)–tris­((4-carboxyl)­phenylduryl)­amine (Ln = Ce,
Pr, Nd, Sm) frameworks have been generated. Four isostructural noninterpenetrating
frameworks (FIR-8 to FIR-11) are constructed
from rod-shaped secondary building units and four other isostructural
frameworks (FIR-12 to FIR-15) based on single
Ln nodes are described as 8-fold interpenetrating dia-type nets. Gas
sorption measurements for FIR-8 give a Langmuir surface
area of 633.8 m2·g–1 and a H2 uptake of 165.2 cm3·g–1 at 77 K and 1 atm. However, FIR-12 with smaller pores
can hardly adsorb any N2 and H2. Because both FIR-8 and FIR-12 crystallize in acentric space
group, the second-harmonic generation (SHG) measurements indicate
that both of them display strong powder SHG efficiencies, which are
approximately 8 and 3 times as strong as that of a potassium dihydrogen
phosphate powder. In addition, the fluorescent emissions of all compounds
in the solid state are also investigated in detail.