Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Nature. 2013 Mar 28;495(7442):461-6. doi: 10.1038/nature11990.
X-ray single-crystal diffraction (SCD) analysis has the intrinsic limitation that the target molecules must be obtained as single crystals. Here we report a protocol for SCD analysis that does not require the crystallization of the sample. In our method, tiny crystals of porous complexes are soaked in a solution of the target, such that the complexes can absorb the target molecules. Crystallographic analysis clearly determines the absorbed guest structures along with the host frameworks. Because the SCD analysis is carried out on only one tiny crystal of the complex, the required sample mass is of the nanogram-microgram order. We demonstrate that as little as about 80 nanograms of a sample is enough for the SCD analysis. In combination with high-performance liquid chromatography, our protocol allows the direct characterization of multiple fractions, establishing a prototypical means of liquid chromatography SCD analysis. Furthermore, we unambiguously determined the structure of a scarce marine natural product using only 5 micrograms of the compound.
X 射线单晶衍射 (SCD) 分析有一个内在的局限性，即目标分子必须以单晶形式获得。在这里，我们报告了一种不需要对样品进行结晶的 SCD 分析方法。在我们的方法中，多孔配合物的微小晶体被浸泡在目标物的溶液中，使得配合物能够吸收目标分子。晶体学分析清楚地确定了被吸收的客体结构以及主体框架。由于 SCD 分析仅在配合物的一个微小晶体上进行，因此所需的样品质量为纳克-微克级。我们证明，只需大约 80 纳克的样品就足以进行 SCD 分析。结合高效液相色谱法，我们的方案允许对多个馏分进行直接表征，建立了液相色谱 SCD 分析的典型方法。此外，我们仅使用 5 微克的化合物就能够明确确定一种稀有海洋天然产物的结构。
