Hou Xiubin, Wang Yingxia, Song Xinbing, Gao Juan, Ma Yurong
MOE Key Laboratory of Cluster Science, Key Laboratory of Medical Molecule Science and Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Soft Matter. 2024 Jun 5;20(22):4422-4433. doi: 10.1039/d4sm00165f.
Biogenic purine crystals can function in vision as light scatters, mirrors, and multilayer reflectors and produce structural colors or depolarization for camouflage. Xanthine crystals form irregular multifocal mirrors in the median ocellus of Archaeognatha. It is important to broaden the study of crystallization strategies to obtain organic crystals with purine rings in the laboratory. In this work, a facile one-step synthesis route to fabricate bio-inspired xanthine crystals is reported for the first time. The obtained rhomboidal xanthine nanoplates have similar morphology and size to biogenic xanthine crystals. Their length and thickness are about 2-4 μm and 50 nm, respectively. Lattice parameters, crystal structure, formation mechanism and optical properties of synthetic single-crystalline xanthine nanoplates were investigated in detail in this work. The obtained xanthine nanoplate crystals are proposed to be anhydrous xanthine with monoclinic symmetry, and the xanthine nanoplates mainly expose the (100) plane. It is proposed that the anhydrous xanthine nanoplates are formed an amorphous xanthine intermediate precursor. The synthetic anhydrous xanthine nanoplates exhibit excellent optical properties, including high diffuse reflectivity, strong depolarization and pearlescent luster. This work provides a new design to synthesize bio-inspired organic molecular crystals with excellent optical properties.
生物源嘌呤晶体可作为光散射体、镜子和多层反射器发挥视觉功能，并产生结构色或去极化以实现伪装。黄嘌呤晶体在古颚目的中单眼形成不规则的多焦点镜子。拓宽结晶策略的研究以在实验室中获得带有嘌呤环的有机晶体很重要。在这项工作中，首次报道了一种制备仿生黄嘌呤晶体的简便一步合成路线。所获得的菱形黄嘌呤纳米片在形态和尺寸上与生物源黄嘌呤晶体相似。它们的长度和厚度分别约为2 - 4μm和50nm。在这项工作中详细研究了合成的单晶黄嘌呤纳米片的晶格参数、晶体结构、形成机制和光学性质。所获得的黄嘌呤纳米片晶体被认为是具有单斜对称性的无水黄嘌呤，且黄嘌呤纳米片主要暴露（100）面。有人提出无水黄嘌呤纳米片是由无定形黄嘌呤中间前体形成的。合成的无水黄嘌呤纳米片表现出优异的光学性质，包括高漫反射率、强去极化和珍珠光泽。这项工作为合成具有优异光学性质的仿生有机分子晶体提供了一种新设计。
