A 400 MHz NMR spectrometer to support chemistry at Sheffield

核磁共振光谱学是表征新化合物和材料的基本技术，也是任何从事合成化学的部门的核心设施。谢菲尔德化学系最近的一系列新任命，以及正在进行的一系列新项目，导致我们的老年套装机器的需求在过去5年中增长了100%。这是一台400 MHz的仪器，它将专门用于非常规实验(1H或13C以外的核；二维实验，特别是涉及不同的核，如1H/19F；对大分子和聚合物的扩散研究；可变温度分析)，这是主要的快速周转服务机器。在新仪器上进行的研究包括：(1)检查大的带正电荷的笼状分子的主-客体化学，这些分子在其中心腔中结合带负电荷的物种；(2)研究手性有机锂试剂(有机化学中的重要中间体)的溶液结构，测量光学异构体相互转化的速率；(3)测量新的聚合物材料的许多性质，如它们的形成速率；它们中单体组分的组成；聚合物分子在溶液中的尺寸分布；由于酸度的变化，胶束的膨胀程度。(4)与CO在体内的缓慢释放有关的具有药学应用的金属羰基络合物的溶液结构和分解速度的测量。(5)在不同温度下准确测定溶液中弱相互作用(氢键、分子间F-F接触)的强度(6)结晶过程中非常早期的事件的测量，由此溶液中的分子开始结合成低聚物集合，这些低聚物集合充当晶体随后生长的‘成核点’。(7)溶液结构、大小、以及具有不寻常的光物理性质的大的多卟啉组件的形成速率。

NMR spectroscopy is an essential technique for characterising new compounds and materials and is a core facility in any department undertaking synthetic chemistry. A recent series of new appointments in the chemistry department at Sheffield, and a range of new projects being undertaken, has resulted in a 100% increase in the demand on our elderly suite of machines in the last 5 years. This application is for a 400 MHz instrument which will be dedicated in particular to non-routine experiments (nuclei other than 1H or 13C; two-dimensional experiments, especially involving different nuclei such as 1H/19F; diffusion studies on macromolecules and polymers; variable-temperature analyses) for which the workhorse fast-turnaround service machine cannot be spared.Studies to be undertakne on the new instrument include(1) Examination of the host-guest chemistry of large positively-charged cage-like molecules which bind negatively charged species in their central cavities;(2) Examination of the solution structure of chiral organolithium reagents (essential intermediates in organic chemistry), and measurement of the rate at which the optical isomers interconvert;(3) Measurements of many properties of new polymeric materials, such as the rates at which their form; the composition of monomer components in them; the size distibution of the polymeric molecules in solution; the degree of swelling of micelles due to changes in acidity.(4) Measurements on the solution structures and rates of decomposition of metal carbonyl complexes which have pharmacetical applications associated with the slow release of CO 'in vivo'(5) Accurate determination of the strengths of weak interactions (hydrogen bonds, intermolecular F---F contacts) in solution at different temperatures(6) Measurement of very early events in the process of crystallisation, whereby molecules in solution begin to associate into oligomeric assemblies which act as 'nucleation points' for subsequent growth of crystals.(7) Examination of the solution structures, sizes, and rates of formation of large multi-porphyrin assemblies which have unusual photophysical properties.