Pseudopolymorph Control of L-Phenylalanine Achieved by Laser Trapping
Pseudopolymorph Control of L-Phenylalanine Achieved by Laser Trapping
复制标题
通过激光捕获实现 L-苯丙氨酸的假多晶型控制
DOI：
10.1021/acs.cgd.8b00796
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发表时间：
2018
影响因子：
3.8
通讯作者：
Teruki Sugiyama
中科院分区：
文献类型：
--
作者：
Chi-Shiun Wu;Pei-Yun Hsieh;Ken-ichi Yuyama;Hiroshi Masuhara;Teruki Sugiyama
通过调节激光功率、偏振度和溶液初始浓度，实现了对L-苯丙氨酸（L-Phe）假多晶型物的激光捕获控制。用波长为1064 nm的连续近红外激光照射不同饱和度的D_2O溶液，在30 min内均能观察到l-Phe结晶，即使是不饱和溶液也能观察到l-Phe结晶。无论是晶须或板状晶体产生取决于给定的条件，并确定由拉曼光谱是两个Phe假多晶型物的一水合物和无水形式，分别。通过改变初始溶液浓度实现了对fl-Phe假多晶型的绝对控制。在不饱和溶液中，激光捕获总是在焦点处产生一个无水晶体，而在常温常压下自发成核是不可能产生的;而在过饱和溶液中，在离焦点500 μm ~ 1 mm的范围内密集地分布着大量的一水晶体。此外，在饱和溶液中，激光功率和偏振有助于假多晶。随着激光功率的增加，线偏振和圆偏振激光照射分别增加了无水晶体和一水合物晶体的形成概率。从类液团簇形成高浓度区域和团簇在激光捕获电磁场作用下的稳定性两个方面讨论了激光捕获诱导苯丙氨酸假多晶的动力学和机理。
We demonstrate pseudopolymorph control ofl-phenylalanine (l-Phe) with laser trapping method by tuning laser power, polarization, and initial solution concentration. When a continuous-wave near-infrared laser beam of 1064 nm was focused at an air/solution interface ofl-Phe D2O solutions with different saturation,l-Phe crystallization was always observed within 30 min-irradiation, even from unsaturated solution. Either whisker- or plate-like crystals were generated depending on given conditions, and identified by Raman spectroscopy to be twol-Phe pseudopolymorphs of monohydrate and anhydrous forms, respectively. The absolute control ofl-Phe pseudopolymorphism was achieved by changing the initial solution concentration. In unsaturated solution, laser trapping always produced only one anhydrous crystal at the focus, which can never be produced on spontaneous nucleation at ordinary temperatures and pressures, while in supersaturated solution, a number of monohydrate crystals were densely distributed in an area ranging from 500 μm to 1 mm away from the focus. Moreover, in saturated solution, laser power and polarization contributed to the pseudopolymorphism. As laser power was increased, linearly and circularly polarized laser irradiation increased the formation probability of the anhydrous and monohydrate crystals, respectively. The dynamics and mechanism of laser trapping-induced pseudopolymorphism ofl-Phe are discussed in view of the formation of a highly concentrated domain consisting of the liquid-like clusters and the stability of the clusters in the domain under electromagnetic field of trapping laser.