Name: coulomb explosion imaging as a tool to distinguish between stereoisomers
Uploaded: 2017-08-18T15:00:00
Description: Watch this Scientific Journal Video about Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers at JoVE.com

我们感谢罗伯特 · 伯杰 （菲利普斯大学马尔堡，德国） 一般激励讨论我们的数据和分子手性的解释。我们对于感谢茱莉亚凯德罗夫斯基、 亚历山大 Schießer 和 Michael Reggelin 从土达姆施塔特 （德国），以及本杰明 Spenger、 曼纽尔 · 马泽瑙尔 Jürgen Stohner 从 ZHAW Wädenswil （瑞士） 提供样品。
Hessen 国家倡议科学和卓越的经济成长，焦点 ELCH （电子系统动力学的手性） 和联邦教育部及研究 (BMBF) 下支持该项目。MS 由阿道夫 · 梅塞尔基金会承认金融支持。

注意： 请务必要熟悉所有可能危害连接与实验和实验室。下面的过程包括第四类激光器、 高电压和真空。物种要追究咨询材料安全数据表 (MSDS)。
 1。 制备 <ol><li>筹备考虑 注： 实际的实验开始前，两个主要选择必须作出; 第一次在调查可能的物种和第二在光谱仪电场。这里假定安装了以前使用其他实验和光谱仪本身不会因此而重新塑造。
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<ol>
	<li>G&#252;bitz, G., Schmid, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chiral+Separation+by+Chromatographic+and+Electromigration+Techniques.+A+Review.">Chiral Separation by Chromatographic and Electromigration Techniques. A Review.</a> Biopharm. Drug Disposition. 22, 291-336 (2001).</li><li>Berova, N., Polaravapu, P. L., Nakanishi, K., Woody, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Comprehensive Chiroptical Spectroscopy. , (2012).</li><li>Bijvoet, J. M., Peerdeman, A. F., van Bommel, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+the+Absolute+Configuration+of+Optically+Active+Compounds+by+means+of+X-rays.">Determination of the Absolute Configuration of Optically Active Compounds by means of X-rays.</a> Nature. 168 (4268), 271-272 (1951).</li><li>Pitzer, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+Determination+of+Absolute+Molecular+Stereochemistry+in+Gas+Phase+by+Coulomb+Explosion+Imaging.">Direct Determination of Absolute Molecular Stereochemistry in Gas Phase by Coulomb Explosion Imaging.</a> Science. 341 (6150), 1096-1100 (2013).</li><li>Pitzer, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Absolute+Configuration+from+Different+Multifragmentation+Pathways+in+Light-Induced+Coulomb+Explosion+Imaging.">Absolute Configuration from Different Multifragmentation Pathways in Light-Induced Coulomb Explosion Imaging.</a> Chem Phys Chem. 17 (16), 2465-2472 (2016).</li><li>Vager, Z., Naaman, R., Kanter, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coulomb+Explosion+Imaging+of+small+molecules.">Coulomb Explosion Imaging of small molecules.</a> Science. 244 (4903), 426-431 (1989).</li><li>Herwig, P. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+the+Absolute+Configuration+of+a+Chiral+Epoxide+in+the+Gas+Phase.">Imaging the Absolute Configuration of a Chiral Epoxide in the Gas Phase.</a> Science. 342 (6162), 1084-1186 (2013).</li><li>D&#246;rner, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cold+Target+Recoil+Ion+Momentum+Spectroscopy:+a+'momentum+microscope'+to+view+atomic+collision+dynamics.">Cold Target Recoil Ion Momentum Spectroscopy: a 'momentum microscope' to view atomic collision dynamics.</a> Physics Reports. 330, 95-192 (2000).</li><li>Ullrich, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recoil-ion+and+electron+momentum+spectroscopy:+reaction-microscopes.">Recoil-ion and electron momentum spectroscopy: reaction-microscopes.</a> Rep. Prog. Phys. 66 (9), 1463-1545 (2003).</li><li>Jagutzki, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+Hit+Readout+of+a+Microchannel+Plate+Detector+With+a+Three-Layer+Delay-Line+Anode.">Multiple Hit Readout of a Microchannel Plate Detector With a Three-Layer Delay-Line Anode.</a> IEEE Trans Nucl Sci. 49 (5), 2477-2483 (2002).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> RoentDek GmbH MCP Delay Line Detector Manual. , (2017).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> RoentDek GmbH The RoentDek Constant Fraction Discriminators CFD8c, CFD7x, CFD4c, CFD1c and CFD1x. , (2017).</li><li>Zeller, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+the+He2+quantum+halo+state+using+a+free+electron+laser.">Imaging the He2 quantum halo state using a free electron laser.</a> PNAS. 113 (51), 14651-14655 (2016).</li><li>Pitzer, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereochemical+configuration+and+selective+excitation+of+the+chiral+molecule+halothane.">Stereochemical configuration and selective excitation of the chiral molecule halothane.</a> J. Phys. B.: At. Mol. Opt. Phys. 49 (23), 234001 (2016).</li><li>Hine, J., Dowell, A. M., Singley, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+Dihalides+as+Intermediates+in+the+Basic+Hydrolysis+of+Haloforms:+IV+Relative+Reactivities+of+Haloforms.">Carbon Dihalides as Intermediates in the Basic Hydrolysis of Haloforms: IV Relative Reactivities of Haloforms.</a> J. Am. Soc. Chem. 78, 479-482 (1956).</li><li>Wales, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+coincidence+detection+algorithm+for+improving+detection+rates+in+coulomb+explosion+imaging.">A coincidence detection algorithm for improving detection rates in coulomb explosion imaging.</a> Nucl. Instr. Meth. in Phys. Res. A. 667, 11-15 (2012).</li><li>Kastirke, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Konstruktion und Aufbau einer UHV-tauglichen COLTRIMS-Kammer. , (2014).</li><li>Calegari, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Charge+migration+induced+by+attosecond+pulses+in+bio-relevant+molecules.">Charge migration induced by attosecond pulses in bio-relevant molecules.</a> J. Phys. B.: At. Mol. Opt. Phys. 49 (14), 142001 (2016).</li><li>Gaie-Levrel, F., Garcia, G. A., Schwell, M., Nahon, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=VUV+state-selected+photoionization+of+thermally-desorbed+biomolecules+by+coupling+an+aerosol+source+to+an+imaging+photoelectron/photoion+coincidence+spectrometer:+case+of+the+amino+acids+tryptophan+and+phenylalanine.">VUV state-selected photoionization of thermally-desorbed biomolecules by coupling an aerosol source to an imaging photoelectron/photoion coincidence spectrometer: case of the amino acids tryptophan and phenylalanine.</a> Phys. Chem. Chem. Phys. 13, 7024-7036 (2010).</li><li>Ablikim, U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+absolute+geometries+of+cis+and+trans+molecular+isomers+by+Coulomb+Explosion+Imaging.">Identification of absolute geometries of cis and trans molecular isomers by Coulomb Explosion Imaging.</a> Sci. Rep. 6, 38202 (2016).</li></ol>

由于各种元器件，COLTRIMS 安装程序需要相当高水平的技术专长，尤其是在真空技术、 粒子检测、 快速的电子和数据分析等领域。在谈到复杂种类调查之前, 它应因此彻底检查如果运行安装程序的方法正确，例如通过执行和分析测量对双原子或原子的物种。
优化的强度和持续时间的激光脉冲与分子射流重叠实现尽可能多尽可能多个电离事件至关重要。随着动量分布可能?...

手性是性质的我们一直令人着迷的研究人员超过 150 年特征。在 19th世纪、 巴斯德、 范特霍夫和别人发现分子可以发生在并不是超级不再依赖-像我们的左手和右手的两个镜像结构。此属性被称为 '手'，从 '手' 的希腊语。
到目前为止，已发现了在热力学性质或左和右旋形式 （两个对映体'） 的能量水平无差异。分析了样品的惯用手，分离对映体，可以使用与其他手性分子相互作用，例如这样做的各种色谱方法。1 （振动） 圆二色性、 (V) CD、 旋光色散，ORD，Chiroptical 方法经常被雇用来区分对映体。2
微观结构测定的时候，这些技术需要附加信息，例如从量子化学计算。唯一的技术正在被广泛接受，直接确定的绝对构型是反常的 x 射线衍射。3
它最近被证明绝对构型的简单手性物种可以由库仑爆炸成像。4,5在这种方法，在气相中的分子是乘以电离，其余内核强烈排斥对方。这斥力导致的分子的快速瓦解 （' 爆炸'）。片段动量相关结构的分子 — — 小分子的大小和方向的动量方向对应出奇好债券轴。使用分子离子束从加速器，开创了分子结构测定的库仑爆炸。6这束箔技术最近也被应用于手性识别。7
与异常的 x 射线衍射、 样品不能结晶，但在气相中提供。这使得库仑爆炸方法挥发性化合物的理想和对 x-射线衍射从而补充。在某些情况下，甚至可以为单个分子已确定惯用手。
在实践中，分子的结构的精确重建已证明困难甚至甲烷衍生物，如中央碳与不同取代基的分子。这被归功于片段之间的相互作用不完全是库仑和并不是所有债券同时都打破。为了获得立体化学信息，尤其是以区分对映体，这种重建是幸运的是不必要的。相反，可以相关不同片段的动量向量，是明显的左和右旋分子的产量。为了得到可靠的结果，至少四个片段动量必须被记录下来。
为了衡量这势头信息，从一个 — — 且只有一个 — — 分子分手片段必须在一个单一的测量步骤中检测到。这种情况通常被称为 '重合检测'。此外，发射方向必须加以分析，这数额在实践中记录的时间和片段的位置影响在列表模式数据格式。
在原子和分子物理学中，技术已经采用静电光谱仪的大规模分离和时间和位置灵敏多命中探测器实现这种测量的方法。最突出的例子是 COLTRIMS （冷目标反冲离子动量谱仪） 设置 — — 也称为反应显微镜。8,9这种实验示意图图 1中给出。相反可以记录以及电子的标准 COLTRIMS，库仑爆炸成像要求只有离子化检测器。
光谱仪和探测器安装在超高真空条件下 (&#60; 1 × 10-9自置居所津贴) 以避免创建从残余气体离子。通过超音速规模扩张所造成的气态自由分子射流提供样品的单分子： 根据蒸汽压力，分子扩大通过小的喷嘴 （大约 50 µ m 直径） 放入真空。实验中，源分庭，这一部分被隔开相互作用区域通常两撇和差异泵浦的阶段。额外的差异抽水部分位于后面的互动区域转储气体射流，从而避免背景气体相互作用区域。
电离辐射与分子射流 90 ° 之下相交。大多数实验室现在用飞秒激光脉冲的同步辐射，快离子或电子冲击虽可能 '弹' 诱使库仑爆炸。
以下协议使重合的离子和飞秒激光成像的运行安装程序可在实验室中的假设。进四个或甚至五个片段诱导库仑爆炸所需的峰值强度必须大约 6 x 1014 W/厘米2。为了避免极长的测量，激光重复频率应 10 千赫或更多。这是关键的因为一方面，重合检测可以只确定如果碎片在激光焦点的概率远远低于 1 每激光脉冲 （理想情况下不超过 10%)。总的碎片率，另一方面，不应低于几千赫因为有关多重碎裂通路的份额通常是小于 10-4。同样令人鼓舞的事实，应该提到的是原则单一碎片事件已足以识别的光学纯样品，配置和检测几百允许确定的对映异构体中丰度未知的对映体组成的样品。

<table border="0" cellpadding="0" cellspacing="0" width="599">
	<tbody>
		<tr height="31">
			<td height="31" style="height:31px;width:179px;">CHBrCl2</td>
			<td style="width:93px;">SigmaAldrich</td>
			<td style="width:147px;">139181-10G</td>
			<td style="width:180px;">or other suitable sample</td>
		</tr>
		<tr height="31">
			<td height="31" style="height:31px;width:179px;">femtosecond laser system</td>
			<td>KMLabs</td>
			<td style="width:147px;">Wyvern500</td>
			<td style="width:180px;"></td>
		</tr>
		<tr height="31">
			<td height="31" style="height:31px;width:179px;">High-reflective mirrors</td>
			<td>EKSMA</td>
			<td style="width:147px;">042-0800</td>
			<td style="width:180px;"></td>
		</tr>
		<tr height="31">
			<td height="31" style="height:31px;width:179px;">mirror mounts</td>
			<td>Newport</td>
			<td style="width:147px;">U100-A-LH-2K&#160;&#160;</td>
			<td style="width:180px;"></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:179px;">focusing mirror (protected silver, f = 75 mm)</td>
			<td>Thorlabs&#160;</td>
			<td style="width:147px;">CM254-075-P01</td>
			<td style="width:180px;">(if available: f = 60 mm)</td>
		</tr>
		<tr height="51">
			<td height="51" style="height:51px;width:179px;">COLTRIMS spectrometer, including electronics and data acquisition system</td>
			<td>RoentDek</td>
			<td style="width:147px;">custom</td>
			<td style="width:180px;">contrary to the standard COLTRIMS, only one detector is needed</td>
		</tr>
	</tbody>
</table>

coulomb explosion imaging as a tool to distinguish between stereoisomers

这篇文章显示了如何使用 COLTRIMS （冷目标反冲离子动量谱仪） 或"反应显微镜"技术来区分对映体 （立体异构体） 的单个分子水平上的简单手性物种。在此方法中，样品的气体分子射流扩展进入真空室和飞秒 (fs) 激光脉冲与相交。高强度的脉冲会导致快速多个电离，点燃了所谓的库仑爆炸，产生几个阳离子 （正电） 片段。静电场指导这些阳离子时间和位置灵敏探测器上。类似于飞行时间质谱仪，每个离子的到达时间产生于它的质量信息。如有盈余，静电场被调整中，发射方向和动能后碎片导致变异在飞行时间和影响位置探测器的一种方式。
每个离子影响创建电子信号在探测器;这个信号是治疗高频率电子和计算机记录事件的事件。注册的数据对应的影响时间和位置。面对这些数据，可以计算能量和每个片段的发射方向。这些值是根据调查，即对债券长度和相对位置的原子，允许以确定分子通过分子的手性的简单手性物种和其他同分异构体的功能分子的结构性质有关。

在这一部分中，我们显示结果的应用。这些种类的原理验证实验由于其简单性和蒸汽压力高的理想选择。同时，利用同步辐射光源的软 x 射线光子诱导多个电离研究了更复杂的物种氟烷。14
CHBrClF
Bromochlorofluoromethane (CHBrClF) 是一个教科书例子为手性分子与手性碳原?...

Watch this Scientific Journal Video about Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers at JoVE.com

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers

作为一种工具来区分立体异构体的库仑爆炸成像

小手性的物种，库仑爆炸成像提供了新的途径来确定单个分子的手性。

This article shows how the COLTRIMS (Cold Target Recoil Ion Momentum Spectroscopy) or the "reaction microscope" technique can be used to distinguish ...

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Organic Chemistry

Chemistry

Unit 1

Transition Metals and Coordination Complexes

Stereoisomerism

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