Hydrogen bonding in pure deuterated ethanol at solid state

Although very familiar, ethanol has a complex phase diagram. Surprisingly, structural information is very scarce. For pure ethanol, only one structural determination at low temperature in 1976 exists so far in the literature. The monoclinic Pc unit cell contains two independent molecules, only H-connected via the enol functional group, but C-H bonds lengths are questionable, as expected from old X-ray data. Neutron data are mandatory to properly explore bonding mechanisms in ethanol, vital for construction of reliable simulations of molecular structures with alcohol groups. Proposal focuses on the precise structure determination of this stable monoclinic phase of perdeuterated ethanol. Due to the monoclinic symmetry, at least 6 orientations (8-10h each) are needed plus one day to prepare the sample in situ: we ask 4 days of beamtime on SXD.

尽管乙醇广为人知，但其相图却极为复杂。令人讶异的是，相关结构信息却十分稀缺。针对纯乙醇，目前文献中仅留存有1976年完成的一次低温结构测定结果。该单斜晶系（monoclinic）Pc空间群晶胞内包含两个独立分子，二者仅通过烯醇官能团形成氢键连接；但正如早期X射线衍射数据所预期的那样，其C-H键长数据存疑。要准确探究乙醇中的成键机制，中子衍射数据（neutron data）是必不可少的，这对构建含醇基团的可靠分子结构模拟具有关键意义。本研究提案旨在精准测定全氘代乙醇（perdeuterated ethanol）的该稳定单斜晶相结构。鉴于单斜晶系的对称性要求，需开展至少6次晶体取向测试（每次耗时8至10小时），外加1天的原位样品制备时间，因此申请在SXD设备上使用4天的束流时间。