A Non-Centrosymmetric Dual-Emissive Metal–Organic Framework with Distinct Nonlinear Optical and Tunable Photoluminescence Properties

A novel dual-emissive metal–organic framework
[Pb3(BPT)2(phen)2]·phen (1) has been obtained by hydrothermal reactions of biphenyl-3,4′,5-tricarboxylic
acid (H3BPT), phen, and lead nitrate in aqueous solution.
It consists of a main right-handed helix and three left-handed helical
chains with the three left-handed helical chains sharing the same
helical axis and further enwinding the main right-handed helical chain
alternately. The BPT3– ligands join the 1D helical
chains into 2D layers with the terminal phen liands extending upward
and downward, which are further interdigitated into a 3D packing supramolecular
architecture through π–π interactions between the
phen molecules of neighbor layers. The second harmonic generation
(SHG) measurement reveals that 1 is nonlinear optical
active with SHG efficiency approximately equivalent to that of the
standard potassium dihydrogen phosphate (KDP), and photoluminescent
investigation displays that complex 1 exhibits distinct
tunable yellow-to-violet photoluminescence by varying the excitation
light.