Nanoencapsulation-Induced Second Harmonic Generation in Pillararene-Based Host–Guest Complex Cocrystals

• DOI: 10.1021/jacs.2c10674
• Publication Date: 2023-01-25T03:13:53Z
• Authors: Haozhong Liang; Yuting Yang; Li Shao; Weijie Zhu; Xiaofeng Liu; Bin Hua; Feihe Huang
• Keywords: Pillar

The features of molecularly preferable centrosymmetric arrangements exclude organic nonlinear optical (NLO) materials for second harmonic generation (SHG) when used in the solid and crystalline states, which greatly limits their applications optoelectronic devices. Herein, a pillar[5]arene (BrP5) is as macrocyclic host to encapsulate NLO molecules, 4-[4'-methoxystyryl]-1-methylpyridinium iodide (OM), 4-[2'-(5'-(dimethylamino)thiophen-2'-yl)vinyl]-1-methylpyridinium (DAST), 4-methoxy-β-nitrostyrene (MNS), alter solid-state packing these molecules manipulate arrangements. BrP5 forms 2:1 host-guest complexes with OM DAST, while it 1:1 complex MNS. Experimental results show that each three guests form nanocapsule architecture along an overall crystal structure. However, random orientation DAST inside nanocapsules breaks local arrangement resulting strong SHG. On contrary, BrP5⊃MNS, MNS cavities are unable break centrosymmetry. They have only one determined one-dimensional (1D) channels BrP5, other adjacent opposite direction. centrosymmetry dipolar chains strictly maintained cancellation polarization, quenching Furthermore, ultrasound-induced crystallization method developed fast preparation composite activity. This work opens new way construct materials, potential high-power lasers, switches, imaging applications.