Funding by the University of East Anglia, the EPSRC (EP/L012855/1) and the EU (H2020-MSCA-IF-2014-EF-ST-658172) is gratefully acknowledged (MTQ).

注意：使用前请咨询所有相关的材料安全数据表（MSDS）。 1. NMR样品制备<ol><li>称量5毫克的N，N-二甲基乙酰胺，放入适合低温NMR管，并在0.6毫升甲苯-d 8的溶解。 </li></ol> 2. NMR实验装置25 <ol><li> NOE光谱采集<ol><li>执行一维NOE（核极化效应）的实验。26 注：NOE效果可以在任何温度下发生。 一维的NOE谱照射，将在SSTD核磁共振实验被照射信号，被记录在-40℃以确保此处使用的样品中的旋转和磁化传递被最小化，并且因此NOE，如果存在，会占优势，在此实验中进行测量。理想情况下，这两个交换核之间的NOE效应建议立即进行删除ð不存在，以避免与SSTD方法干扰。 </li></ol></li><li> SSTD核磁共振实验设置<ol><li>通过在软件的命令行第一打字EJ插入在磁体样品打开气流。然后，把磁铁顶部的样品，然后键入IJ。等到样品是磁铁内部。 </li><li>一旦样品是在命令行中的磁铁，类型edte。温度变化与第一个选定的温度进行了实验（295.5 K的这种情况下）。让样本稳定在所选择的温度为至少20分钟。 </li><li>执行对样品的一维1 H-NMR实验。 <ol><li>创建的1 H-NMR实验的一个新的数据集。对于此点击文件/新建并命名新的实验。 </li><li> 锁 ， 灵魂 ，topshim，getprosol和RGA：依次等待前面的命令完成输入。 </li><li>键入&lt;EM&gt; ZG收购质子实验。一旦完成型EFP和APK傅里叶变换，并调整阶段。 </li></ol></li><li>创建一个新的数据集，例如，一个1 H NMR实验。对于此点击文件/新建并命名新的实验。 </li><li>在这个新的数据集，在命令行中键入RPAR。选择“STDDIFF”参数集从列表中的一个，例如STDDIFFESGP，然后点击“读取”，然后选择“阅读”（ 图1）。另外， 所有输入RPAR STDDIFFESGP做到这一点。 注：实验可以用此脉冲序列来执行。然而，在我们的实验中使用的脉冲程序是STDDIFF。 </li><li>选择STDDIFF脉冲序列，点击有三个点在PULPROG线（ 图2和3）的按钮。 </li><li>开展SSTD NMR实验前，校准1小时90°硬PULSE（P1）。为了这个目的，确保该样品是在磁铁在所需的温度（步骤2.2.2）。在命令行键入pulsecal并在更高的功率（在这种情况下PL1 = -1分贝）， 即复制90°脉冲的值，所述一个，使该最短脉冲（ 图4）。 </li><li>介绍在实验校准硬脉冲的值。类型getprosol 1H（在步骤2.2.7得到p1的值）（用于PL1值）（ 图5）。 </li><li>设置整形脉冲的长度。 P13型和引进50000微秒（ 图6）的值。 </li><li>设置的选择脉冲形状。要做到这一点，进入电源，然后点击旁边的“编辑...”按钮形状（ 图7）。进入整形脉冲13和选择：GAUS 1.1000（ 图8）。 </li><li>设置的选择脉冲功率（SP13）。它设置为合适的东西， 也就是 </em&gt;，40-60分贝之间在该系统上（对应于大约120赫兹的场强度）（ 图8）。过度的场强会导致不可接受的饱和效应。27-29 注50块是在我们的情况最佳。考虑到，这是一个衰减比例，因此值越小越高射频的功率。因为它对应于饱和高斯级联，施加长时间（几秒），SP13不应去低于40分贝（如果需要的话，请参考仪器的规格，如在高功率长脉冲可能会损坏probehead）。根据我们的经验硬1小时90°脉冲（-1分贝在这项工作）的衰减上述41-61分贝工作正常。尝试总是选择最高的衰减可能导致类似的饱和度。 </li><li> NS型并将其设置为8和类型DS并将其设置为4。 </li></ol></li></ol> 3.核磁共振数据采集的数字处理能力25 <ol><li> SSTD核磁共振实验采集<ol><li>打开步骤2.2.3进行检查，其中，将被照射的信号与1 H NMR实验。为此，在搜索软件浏览器的实验中，右键单击该数据集，然后点击“在新窗口中显示”。 </li><li>移动光标线的信号的中心到照射并写下以ppm化学位移。选择将在实验中使用的光谱宽度。 注意：在这种情况下，这将被照射的信号是在2.17 ppm，且所使用的谱宽为1.46 ppm的。确保没有化学位移改正或者因照射频率可以正确设置。 </li><li>去之前创建的SSTD NMR实验在2.2节中提到的设置。 </li><li>创建与照射的频率的列表。为此，在命令行中键入fq2list并选择现有列表。 </li><li>编辑列表照射频率，包括在3第一行（ 图9）以下的数据： 行1 P（表示后面的数据是用ppm）; 行2 中的信号的频率，以ppm的照射，如在3.1测定。 1;行3.40 ppm的 （即远离化合物的1 H信号，使得在该频率的照射不会影响光谱的频率）。 </li><li>使用新名称保存列表，然后在命令行中键入fq2list并选择刚才创建的列表。 </li><li>居中研究之中，式O1P并选择作为实验，将被照射的信号的化学位移的中心上的信号的实验。 </li><li>类型SW以选择谱宽（1.46 ppm的在这种情况下，但也可以选择任何其它光谱宽度）。 注意：如果改变光谱宽度之后获得的采集时间太长（将介绍在光谱更多的噪声）它CAÑ通过键入AQ以提供所需的自由感应衰减（FID）分辨率（FIDRES，0.25赫兹在这种情况下）进行调整。 </li><li>选择扫描间延迟放宽D1的价值。确保它是T最慢的放松的1中的至少1至5倍的值 质子。 注意：我们将其设置为40秒，这是在实验中最长的饱和时间（D20）。在这种方式，所有的实验都将保持相同的总“每次扫描”的时间（延迟+饱和时间+脉冲+采集时间）。 </li><li> D1型并将其设置为40秒。 </li><li>通过键入D20并将其设置为40秒设定的饱和时间的第一个值。确定接收机增益（RG）通过键入RGA自动。 </li><li>创建通过键入iexpno下一步实验。键入D20在这个实验中选择20秒的饱和时间。键入RGA自动确定RG。 </li> &lt;利&gt;重复D20 = 10，5，2.5％，1.25，0.625，0.3秒的最后一步。 </li><li>一旦所有的实验的创建，打开第一个和在命令行键入multizg和指定的实验8在这种情况下的数量（ 即 ，multizg 8）。 </li></ol></li><li> SSTD核磁共振实验处理<ol><li>打开从EXPNO 1集合的PROCNO 1（方法号）（实验号）（具有较高的饱和时间）。 </li><li>在命令行中键入磅并将其值设置为1.5。 注：对于具有非常高的信号 - 噪声比这个值能够减少光谱;相反地​​，它可以用于嘈杂实验可以增加，如果光谱分辨率不会受到严重影响。 </li><li>在PROCNO = 2（ 图10）命令行中键入EFP和工艺FID＃= 1（“关于共振”谱）。 </li><li>通过点击交互式相位修正 b校正实验的相utton并保存为一个二维实验。保存并退出（ 图11）。 </li><li>在命令行中键入代表1转到PROCNO 1。 </li><li>在PROCNO = 3（ 图12）命令行中键入EFP和工艺FID＃= 2（“非共振”谱）。 </li><li>在命令行键入.MD然后代表2，以显示与两个处理光谱的多个显示窗口：2（一个在中间饱和的信号）和3（其中饱和脉冲串在40 ppm的施加一个）（ 图13）。 </li><li>点击一个三角征（ 图13）来计算差谱并将其保存在PROCNO 4.退出多个显示窗口的按钮。 </li><li>选择用于在左侧（在其中将观察到饱和，由于化学交换过程转移处的信号）的信号的积分的范围。总是PROCNO 3和4 PROCNO同一区域整合。 <br/&gt;注：在该实验中所用的积分范围是2.55 - 2.67 ppm的。 </li><li>一旦整合，进入“积分”选项卡中的每个实验和复制的价值“积分[ABS]”（ 图14）。 </li><li>通过在PROCNO 3.积分即ηSSTD的40秒（ηSSTD =自旋饱和转移差异参数）的饱和时间的值除以在PROCNO 4的积分。21 </li><li>用同样的方法用不同的饱和次实验的其余部分。 </li></ol></li></ol> 4.数据分析30 <ol><li>对数据的分析来获取动力学参数<ol><li>画出获得ηSSTD值与饱和的时间。21 </li><li>执行指数拟合到所获得的曲线调节到方程 <img alt="式（1）" src="/files/ftp_upload/54499/54499eq1.jpg" /> <img a所述=“公式2”SRC =“/文件/ ftp_upload / 54499 / 54499eq2.jpg”/&gt; <img alt="公式3" src="/files/ftp_upload/54499/54499eq3.jpg" /> = <img alt="公式4" src="/files/ftp_upload/54499/54499eq4.jpg" />在很长的饱和时间 t =时间</li><li>计算ηSSTD MAX和δ的值，并用它们来计算该速率常数根据如下方程式弛豫时间（T 1A）的值（k）和： <img alt="公式5" src="/files/ftp_upload/54499/54499eq5.jpg" /> ŧ1A =旋A的纵向弛豫时间常数 K =相互现场交流动力学速率常数<ol><li>由获得动力学速率常数： <img alt="公式6" src="/files/ftp_upload/54499/54499eq6.jpg" /></li></ol></li></ol></li><li>情节的Eyring获得热力学参数<ol><li>情节LN（K / T）对1 / T（T =绝对温度），使用母牛的值<html>在不同温度下抽动速度。 </li><li>执行线性拟合来调整所得到的Eyring方程中的数据： <img alt="公式7" src="/files/ftp_upload/54499/54499eq7.jpg" /> <img alt="式（8）" src="/files/ftp_upload/54499/54499eq8.jpg" /> <img alt="公式9" src="/files/ftp_upload/54499/54499eq9.jpg" /> <img alt="10式" src="/files/ftp_upload/54499/54499eq10.jpg" /> R =气体常数 KB = Boltzmann常数 T =绝对温度</li><li>计算热力学参数ΔH≠和ΔS≠。 </li><li>计算EA（298）和ΔG值≠使用以下公式（298）： <img alt="11式" src="/files/ftp_upload/54499/54499eq11.jpg" /> <img alt="12式" src="/files/ftp_upload/54499/54499eq12.jpg" /> S / ftp_upload / 54499 / 54499eq13.jpg“/&gt; <img alt="14式" src="/files/ftp_upload/54499/54499eq14.jpg" /> </li></ol></li></ol>

<ol>
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V., Dragic, Z., Wagner, B., Gathje, H., Kelm, S., Ernst, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitivity+Enhancement+in+Saturation+Transfer+Difference+(STD)+Experiments+Through+Optimized+Excitation+Schemes.">Sensitivity Enhancement in Saturation Transfer Difference (STD) Experiments Through Optimized Excitation Schemes.</a> Magn Reson Chem. 45, 720-724 (2007).</li><li>Ley, N. B., Rowe, M. L., Williamson, R. A., Howard, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimising+Selective+Excitation+Pulses+To+Maximize+Saturation+Transfer+Difference+NMR+Spectroscopy.">Optimising Selective Excitation Pulses To Maximize Saturation Transfer Difference NMR Spectroscopy.</a> RSC Adv. 4, 7347-7351 (2014).</li><li>Antanasijevic, A., Ramirez, B., Caffrey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+Sensitivities+of+WaterLOGSY+and+Saturation+Transfer+Difference+NMR+Experiments.">Comparison of the Sensitivities of WaterLOGSY and Saturation Transfer Difference NMR Experiments.</a> J. Biomol. NMR. 60 (1), 37-44 (2014).</li><li>Jarek, R. L., Flesher, R. J., Shin, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetics+of+Internal+Rotation+of+N,N-Dimethylacetamide:+A+Spin-Saturation+Transfer+Experiment.">Kinetics of Internal Rotation of N,N-Dimethylacetamide: A Spin-Saturation Transfer Experiment.</a> J. Chem. Ed. 74, 978-982 (1997).</li><li>Forsen, S., Hoffman, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exchange+Rates+by+Nuclear+Magnetic+Multiple+Resonance.+III.+Exchange+Reactions+in+Systems+with+Several+Nonequivalent+Sites.">Exchange Rates by Nuclear Magnetic Multiple Resonance. III. Exchange Reactions in Systems with Several Nonequivalent Sites.</a> J. Chem. Phys. 40, 1189-1196 (1964).</li></ol>

The authors declare that they have no competing financial interests.

One of the more obvious advantages of this methodology is that the rate constants and the relaxation time for a given temperature can be obtained with a single set of experiments, with a robust pulse sequence (the same used for STD experiments to study protein-ligand interactions, which is typically found within the available set of experiments from the spectrometer manufacturer). This simplifies the experimental setup since there is no need to measure T1 or reach steady state saturation. Besides, it is remarkable that this method does not depend on the magnet strength, as coalescence methods. On the other hand, the main limitation is that this technique cannot be applied to chemical exchange processes too fast or too slow, which would depend on the temperature range of the NMR machine or the solvents used.
This new technique for the calculation of kinetic parameters can be applied to a great variety of substrates and its applicability has already been demonstrated with some interesting molecules.21 The kinetic parameters of the 4-N,N-dimethylamido[2.2]paracyclophane, a challenging substrate in which the signal of one of the methyl groups of interest is overlapped with other signals from the molecule, were successfully calculated using SSTD NMR. Interestingly, this methodology can be applied as long as one of the signals of study is isolated. SSTD NMR is also a useful protocol for the calculation of kinetic parameters in molecules in which the coalescence temperature is so high that the molecule decomposes before reaching it. This is the case with PtCl2(dimethylallene)(pyridine), in which the methodology was successfully applied without the need of reaching coalescence. The choice of solvents and temperatures is critical to obtain good results, since the chemical exchange rates can vary significantly with these parameters. Moreover, in addition to the criteria in a normal NMR experiment, key steps in a SSTD NMR experiment are the selectivity of the irradiation as well as the temperature control. Both factors have to be precise to guarantee the success of the experiment.
The representative results presented here are for the kinetics of intramolecular chemical exchange, but the technique can also be applied to study the kinetics of intermolecular chemical exchange and also ligand exchange, common processes in the dynamic behavior of transition metal complexes. 
Finally, providing a proper modification of the equations is made,32 this method could be extended to deal with multi-site exchange and unequal populations, as it has been done in former double resonance experiments,8-9 increasing the usefulness of this technique for the study of chemical exchange processes in challenging compounds.

化学交换通常是指任何分子间或分子内的方法，其中一个核从一个环境移动到另一个，其中其核磁共振参数（化学位移，标量偶合，偶极耦合，松弛率）不同。有有机和有机分子（ 例如，在联芳基旋转障碍，环翻转障碍和构象平衡，氮反转，配体结合，简配体交换和互变异构）化学交换的例子不胜枚举1-3化学汇率相关交换过程的屏障的热力学，因此，其研究是至关重要的，以了解这些系统的分子动力学。 核磁共振动态交换的经典标志是在NMR信号随着温度的变化的线形了戏剧性的变化。在低温下，该过程是缓慢的，两个不同的化学位移是安装前后VED。在高温下，这两个信号合并成一个信号，它被称为“聚结”。在中间温度时，信号变得非常广泛。核磁共振谱的化学交换这种敏感性使得NMR一个非常强大的方法来研究分子动力学解决方案。两种方法已被采用，主要在溶液中的动态过程的研究。线形分析，4-7和自旋饱和转移实验8-9此外，它也是值得一提的反转传输方法10，投洽会项目11直接提取速率常数，这是简单的系统交换测量相对有效的办法。虽然这些方法在大多数情况下，得到了很好的效果，它们，然而，有许多缺点。该线形态分析的主要缺点是在一些样品中达成合并所需要的高温。12，主要要考虑的问题时，CArrying出自旋饱和转移实验是：到达交换位点之间的稳态饱和转移所需的很长的饱和时间，并且需要确定的纵向弛豫时间常数，T 1，这是很困难的，如果有不同的重叠在研究的区域信号。13 作为我们在有机金属机制调查的一部分，14-16我们组正在研究铂-丙二烯络合物在溶液中的fluxional行为。这是一个复杂的任务，包括在至少三个不同的过程，其中之一是金属的丙二烯轴线之一左右的π面交换或旋转。我们遇到的正常的VT实验和已经在类似的系统之前采用线形分析技术，17-19不适合于我们的研究中，由于在我们的铂-丙二烯络合物的非常缓慢的旋转，使得的聚结温度SIG的兴趣比络合物分解的温度高良。 为了克服这一限制，我们开发和最近报道了新的NMR协议（SSTD NMR）研究相互现场的化学交换过程。20顾名思义本方法结合使用的小分子的自旋饱和转移的方法，用饱和转移差异核磁共振方法通过测量沿发生化学交换小分子日趋饱和时间（积曲线）瞬态自旋饱和转移用于蛋白质-配体相互作用的研究中，21-24。 用这种新的方法（SSTD NMR）我们已经表明，我们可以得到超过传统方法的一些额外的优点小有机和有机金属分子的分子内的化学交换的动力学参数：不需要的信号的聚结，因此，更灵活的温度范围内可以使用在研究中;信号重叠不干扰，虽然交换共振中的至少一个应隔离;没有必要测量Ť1或达到稳态饱和;速率常数的值被直接测量，并在相同的实验，获得Ť1值，只用一组实验。所述SSTD核磁共振方法的另一个显着的优点是，相对于线形分析，动力学速率常数的测定是不通过与高磁场相关联的聚结温度的增加的限制。因此，我们的方法，然后很好拨到低和高磁场。本文旨在帮助新用户使用这种新方法，以自己的系统进行化学交换，并介绍了样品制备，实验装置，数据采集，并在一个简单的有机分子的数据处理和分析的例子。

<table border="0" cellpadding="0" cellspacing="0" width="1616">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">N,N-dimethylacetamide</td>
			<td style="width:691px;">Aldrich</td>
			<td style="width:119px;">38840</td>
			<td style="width:167px;">Acute toxicity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Toluene-d8</td>
			<td style="width:691px;">Fluorochem</td>
			<td style="width:119px;">D-005</td>
			<td>Flammable and toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">500MHz 7&#34; Select Series NMR Tubes</td>
			<td style="width:691px;">GPE LTD</td>
			<td style="width:119px;">S-5-500-7</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">TopSpin 2.1</td>
			<td>TopSpin program, Bruker Corp., http://www.bruker.com/products/mr/nmr/nmr-software/software/topspin/ (2015).</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Origin 6.0</td>
			<td>Origin 6.0 software, OriginLab Corp., http://originlab.com.</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bruker Avance III 500 MHz fitted with 5mm broadband observed BBFOplus Z-gradient SmartProbeTM probe</td>
			<td style="width:691px;">&#160;Bruker Corp., http://www.bruker.com</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bruker Avance I 500 MHz Inverse Triple Resonance NMR spectrometer fitted with a 5mm TXI Z-gradient probe</td>
			<td style="width:691px;">&#160;Bruker Corp., http://www.bruker.com</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:639px;">Ceramic Spinner standardbore shimsystems (5 mm)</td>
			<td>&#160;Bruker Corp., http://www.bruker.com</td>
			<td style="width:119px;">H00804</td>
			<td></td>
		</tr>
	</tbody>
</table>

spin saturation transfer difference nmr (sstd nmr): a new tool to obtain kinetic parameters of chemical exchange processes

该协议详细介绍了新的自旋饱和转移差异核磁共振协议（SSTD NMR），最近在我们的小组开发研究，是很难用传统的方法来分析相互现场的化学交换过程。顾名思义，该方法中，通过测定瞬态自旋饱和转移沿增加饱和时间（建立结合用于小分子的自旋饱和转移的方法，用饱和转移差异为蛋白 - 配体相互作用的研究采用（STD）NMR法-up曲线）在发生化学交换小的有机和有机分子。 这种方法比现有的优点是：没有必要到达交换信号的聚结;该方法可以，只要可以应用作为交换位点是分离的一个信号;没有必要测量Ť1或达到稳态饱和;速率常数VA梅毒被直接测量，并且在相同的实验中获得Ť1值，只用一组实验。 为了测试该方法，我们研究了N，N- -dimethylamides的受阻旋转，对于其可用于比较大量的数据的动态。使用SSTD得到的热力学参数非常类似于所报告的那些（自旋饱和转移技术和线形分析）。该方法可以适用于无法通过以前的方法来研究更有挑战性基板。 我们设想，在简单的实验设置，并且该方法的广泛适用性极大各种基材将使这个之间无核磁共振广泛的专业知识的有机和有机金属化学家的常用技术。

所述SSTD NMR技术是在N，N-酰胺键的旋转施加的动力学参数的计算二甲基乙酰胺。21这31个简单的例子为哪些用于比较大量的数据可以在文献中找到。 周围的酰胺键的受阻旋转，由于在共振形式部分双键特征，区别在1 H-NMR光谱均为甲基成两个信号（2.61和22.5℃下2.17 ppm的）。在2.17分钟（我B）中的甲基的信号的自旋饱和导致其在1 H-NMR信号的消失。在我B，饱和其他甲基（我A）的传输的饱和由于内部旋转处理可以通过的1 H的强度的信号的下降在2.61 ppm的被观察到。该magnitu这种减少的日将取决于饱和时间。 图15示出了在22.5℃下的N，N-二甲基乙酰胺的1 H NMR谱，和扩展显示没有光谱（a）和与（b）该甲基的饱和基在2.17 ppm时，以及在差异谱（c）中，用于计算ηSSTD的值。的ηSSTD因子计算由（a）中，在协议中解释了我A的光谱的积分值除以我A在SSTD NMR谱（c）该积分的值。所获得的ηSSTD在不同温度下的每个饱和时间为值被收集在表1中。ηSSTD的相对于饱和时间所获得的值的曲线图，得到在其中一个平台在较高的饱和倍达到指数曲线。为一定的温度，在曲线的指数拟合允许速率的计算常数（k）和所测量的信号（T 1A）（ 图16）。的1 H弛豫时间图17显示所有得到的曲线与拟合得到第k和T 1A值一起。 最后，LN的积（K / T）对1 / T和配合到的Eyring方程（ 图18）被用来计算活化的焓和熵。所确定的激活参数示于表2中 ，用不同的方法计算出的先前报告的参数一起。 如可在表2中可以观察到，用自旋饱和转移差异技术（SSTD NMR）中获得的活化参数的值是在与数据优良协议使用其他技术，如SST NMR或以前报道线形态分析。广泛报道ΔS‡值是由于在此参数NMR技术测量的难度。31至于激活参数的其余部分，与我们的方法获得的值不仅确实类似于那些已经报道而且更准确的，因为我们的误差（SD）是在所有情况下要小。 <img alt="图1" src="/files/ftp_upload/54499/54499fig1.jpg" /> 图1：输入 RPAR 实验之后列表 。图中显示了其中STDDIFFESGP应选择不同的参数集。 <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/54499/54499fig2.jpg" /><br/&gt; 图2：。采集参数按钮，在一个红色正方形高亮导致不同的脉冲程序的列表<a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig2large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54499/54499fig3.jpg" /> 图3：。 脉冲程序列表的图显示了实验（STDDIFF）选定的脉冲程序<a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54499/54499fig4.jpg" /> 图4：弹出窗口90°脉冲校准后出现图中显示的数值标定90。<html> ＃176;脉冲在不同的功率电平。 <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/54499/54499fig5.jpg" /> 图5：。 在命令行的截图图显示了如何引入校准硬脉冲值<a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig5large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> <img alt="图6" src="/files/ftp_upload/54499/54499fig6.jpg" /> 图6： 对整形脉冲的长度值图显示了如何引入值成形脉冲的长度。<html> g6large.jpg“目标=”_空白“&gt;点击此处查看该图的放大版本。 <img alt="图7" src="/files/ftp_upload/54499/54499fig7.jpg" /> 图7：。 采集参数图显示了电源参数， <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig7large.jpg" target="_blank">请点击这里查看该图的放大版本。</a> <img alt="图8" src="/files/ftp_upload/54499/54499fig8.jpg" /> 图8：为形脉冲参数的脉冲形状的值将在13行介绍<a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig8large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <html> PLOAD / 54499 / 54499fig9.jpg“/&gt; 。图9：照射频率列表的数字包括在3第一行如下的数据： 行1 P（表示后面的数据是用ppm）; 行2 中的信号的频率，以ppm的照射，测得 。 在3.1.1;行3.40 ppm的 （即远离化合物的1小时，这样的信号在频率并不影响光谱辐射的频率） <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig9large.jpg" target="_blank">点击此处查看该图的放大版本。</a> <img alt="图10" src="/files/ftp_upload/54499/54499fig10.jpg" /> 图10： 第一个FID的处理由图可知，键入EFP后出现的弹出窗口。<html> NK“&gt;点击此处查看该图的放大版本。 <img alt="图11" src="/files/ftp_upload/54499/54499fig11.jpg" /> 图11：。 相位校正屏幕截图显示了手动相位校正窗口<a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig11large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图12" src="/files/ftp_upload/54499/54499fig12.jpg" /> 图12： 在第二FID加工的数字显示，键入EFP后出现的弹出窗口。 <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig12large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 图13“SRC =”/文件/ ftp_upload / 54499 / 54499fig13.jpg“/&gt; 图13：光谱2和3的按钮，在红色正方形突出了多种显示的是一个计算差值光谱。 <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig13large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图14" src="/files/ftp_upload/54499/54499fig14.jpg" /> 图14：。积分卡图显示了绝对和相对积分值<a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig14large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> <img alt="图15" src="/files/ftp_upload/54499/54499fig15.jpg" /> 图15： 结构和 1 </stron<html> g&gt;的氮 H-NMR 光谱 ， 甲苯-d 8，N-二甲基乙22.5℃（a）由照射前2.13至2.66 ppm为单位的区域的1 H NMR扩张。相同的区域（b）的膨胀甲基的照射后在2.17 ppm的。 （ 三 ）差光谱[（A） - （B）]。 <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig15large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图16" src="/files/ftp_upload/54499/54499fig16.jpg" /> 图16：ηSSTD 的情节 和它的指数拟合在278 K.转载自职权21与皇家化学学会许可的证明资料的例子 。http://ecsource.jove.com/files/ftp_upload/54499/54499fig16large.jpg“目标=”_空白“&gt;点击此处查看该图的放大版本。 <img alt="图17" src="/files/ftp_upload/54499/54499fig17.jpg" /> 图17： 地块 ηSSTD 主场迎战在不同温度下的饱和时间，图中显示了N，N-二甲基乙酰胺和所获得的速率常数和弛豫时间的表中的情节。 <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig17large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图18" src="/files/ftp_upload/54499/54499fig18.jpg" /> 图18： 阴谋的Eyring图显示了N，N-二甲基乙酰胺剧情。 <a href="http://ecsource.jove.com/files/ftp_upload/54499/54499fig18large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td rowspan="2"> ŧSAT（秒） </td><td> ηSSTD </td><td> ηSSTD </td><td> ηSSTD </td><td> ηSSTD </td><td> ηSSTD </td><td> ηSSTD </td><td> ηSSTD </td></tr><tr><td> （T = 278 K） </td><td> （T = 283 K） </td><td> （T = 285.5 K） </td><td> （T = 288 K） </td><td> （T = 290.5 K） </td><td> （T = 293 K） </td><td> （T = 295.5 K） </td></tr><tr><td> 40 </td><td> 0.2526 </td><td> 0.3957 </td><td> 0.4671 </td><td> 0.5461 </td><td> 0.626 </td><td> 0.6969 </td><td> 0.7535 </td></tr><tr><td> 20 </td><td> 0.2526 </td><td> 0.3957 </td><td> 0.4671 </td><td> 0.5461 </td><td> 0.626 </td><td> 0.6969 </td><td> 0.7535 </td></tr><tr><td> 10 </td><td> 0.2383 </td><td> 0.3806 </td><td> 0.4537 </td><td> 0.5355 </td><td> 0.6199 </td><td> 0.6969 </td><td> 0.7535 </td></tr><tr><td>五</td><td> 0.1904 </td><td> 0.3193 </td><td> 0.3919 </td><td> 0.481 </td><td> 0.5734 </td><td> 0.6638 </td><td> 0.7318 </td></tr><tr><td> 2.5 </td><td> 0.1263 </td><td> 0.2204 </td><td> 0.2812 </td><td> 0.3589 </td><td> 0.4449 </td><td> 0.5461 </td><td> 0.626 </td></tr><tr><td> 1.25 </td><td> 0.0761 </td><td> 0.1353 </td><td> 0.171 </td><td> 0.2247 </td><td> 0.2868 </td><td> 0.3732 </td> &lt;TD&gt; 0.4449 </td></tr><tr><td> 0.625 </td><td> 0.0467 </td><td> 0.0739 </td><td> 0.099 </td><td> 0.1327 </td><td> 0.171 </td><td> 0.2291 </td><td> 0.2758 </td></tr><tr><td> 0.3 </td><td> 0.0238 </td><td> 0.044 </td><td> 0.0472 </td><td> 0.0644 </td><td> 0.0847 </td><td> 0.1169 </td><td> 0.1463 </td></tr></tbody></table> 表1：ηSSTD的值的表格示出了在温度278-295.5 K的范围在不同的饱和时间N，N-二甲基乙酰胺中得到的值<table border="0" cellpadding="0" cellspacing="0" width="585"><colgroup><col /><col span="5" /></colgroup><tbody><tr height="34"><td height="34" style="height:34px;width:145px;"> 方法 </td><td style="width:88px;"> SSTD NMR </td><td rowspan="2" style="width:88px;"> SST NMR 31 </<html> TD&gt; <td style="width:88px;"> 线形分析 </td><td style="width:88px;"> 线形分析 </td><td style="width:88px;"> 线形分析 </td></tr><tr height="22"><td height="22" style="height:22px;width:145px;"> 参数 </td><td style="width:88px;"> （这项工作） </td><td style="width:88px;"> （1 H NMR）4 </td><td style="width:88px;"> （1 H NMR）5- </td><td style="width:88px;"> （13 C NMR）6 </td></tr><tr height="21"><td height="21" style="height:21px;width:145px;"> Ë298（KJ摩尔-1） </td><td style="width:88px;"> 79.7±0.1 </td><td style="width:88px;"> 73.1±1.4 </td><td style="width:88px;"> 70.5±1.7 </td><td style="width:88px;"> 82.0±1.3 </td><td style="width:88px;"> 79.5±0.4 </td></tr><tr height="21">21px;宽度：145px;“&gt;ΔH‡（KJ摩尔-1） </td><td style="width:88px;"> 77.2±0.1 </td><td style="width:88px;"> 70.6±1.4 </td><td style="width:88px;"> 68 </td><td style="width:88px;"> 79.5±0.4 </td><td style="width:88px;"> 76.6±0.4 </td></tr><tr height="21"><td height="21" style="height:21px;width:145px;"> ΔS‡（J摩尔-1 K -1） </td><td style="width:88px;"> 11.5±0.4 </td><td style="width:88px;"> -10.5±5.0 </td><td style="width:88px;"> -15.0±5.1 </td><td style="width:88px;"> 13±8 </td><td style="width:88px;"> 3±4 </td></tr><tr height="21"><td height="21" style="height:21px;width:145px;"> ΔG‡298（KJ摩尔-1） </td><td style="width:88px;"> 73.8±0.1 </td><td style="width:88px;"> 73.7±2.0 </td><td style="width:88px;"> 720.5 </td><td style="width:88px;"> 75.3±0.4 </td><td style="width:88px;"> 75.7±0.4 </td></tr><tr height="21"><td height="21" style="height:21px;width:145px;"> 溶剂 </td><td style="width:88px;">允差D 8 </td><td style="width:88px;">允差D 8 </td><td style="width:88px;"> 四氯化碳 </td><td style="width:88px;">丙酮-d 6 </td><td style="width:88px;">整齐</td></tr></tbody></table> 表2： 激活参数表显示N的内旋的激活参数，N-二甲基乙酰胺通过与使用用于分析不同核磁共振方法获得的相同的参数进行比较的SSTD NMR法获得在此表4,5,6误差。参考标准偏差误差（SD）。 （从21引用转载来自皇家SOC许可化学iety）。

Watch this Scientific Journal Video about Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes at JoVE.com

Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

A detailed protocol describing the SSTD NMR method is presented here to help new users apply this new method to obtain the kinetic parameters of their own systems undergoing chemical exchange.

自旋饱和转移差异核磁共振（NMR SSTD）：一种新的工具来获得化学交换过程的动力学参数

This detailed protocol describes the new Spin Saturation Transfer Difference Nuclear Magnetic Resonance protocol (SSTD NMR), recently developed in our ...

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Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

Advanced Nuclear Magnetic Resonance Spectroscopy

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17.6K 次观看.  University of East Anglia. A detailed protocol describing the SSTD NMR method is presented here to help new users apply this new method to obtain the kinetic parameters of their own systems undergoing chemical exchange.

视频: Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

Methods to Identify the NMR Resonances of the 13C-Dimethyl N-terminal Amine on Reductively Methylated Proteins

Nuclear magnetic resonance (NMR) spectroscopy is a proven technique for protein structure and dynamic studies. To study proteins with NMR, stable magnetic isotopes are typically incorporated metabolically to improve the sensitivity and allow for sequential resonance assignment. Reductive 13C-methylation is an alternative labeling method for proteins that are not amenable to bacterial host over-expression, the most common method of isotope incorporation. Reductive 13C-methylation is a chemical reaction performed under mild conditions that modifies a protein&#39;s primary amino groups (lysine &#949;-amino groups and the N-terminal &#945;-amino group) to 13C-dimethylamino groups. The structure and function of most proteins are not altered by the modification, making it a viable alternative to metabolic labeling. Because reductive 13C-methylation adds sparse, isotopic labels, traditional methods of assigning the NMR signals are not applicable. An alternative assignment method using mass spectrometry (MS) to aid in the assignment of protein 13C-dimethylamine NMR signals has been developed. The method relies on partial and different amounts of 13C-labeling at each primary amino group. One limitation of the method arises when the protein&#39;s N-terminal residue is a lysine because the &#945;- and &#949;-dimethylamino groups of Lys1 cannot be individually measured with MS. To circumvent this limitation, two methods are described to identify the NMR resonance of the 13C-dimethylamines associated with both the N-terminal &#945;-amine and the side chain &#949;-amine. The NMR signals of the N-terminal &#945;-dimethylamine and the side chain &#949;-dimethylamine of hen egg white lysozyme, Lys1, are identified in 1H-13C heteronuclear single-quantum coherence spectra.

Methods to Identify the NMR Resonances of the 13C-Dimethyl N-terminal Amine on Reductively Methylated Proteins

Two methods for assigning the &#945;- and &#949;-dimethylamine nuclear magnetic resonance signals of a reductively 13C-methylated N-terminal lysine are described. One method utilizes the pH-induced selectivity of the reductive methylation reaction, and the other uses aminopeptidase to selectively remove the N-terminal lysine.

Nuclear magnetic resonance (NMR) spectroscopy is a proven technique for protein structure and dynamic studies. To study proteins with NMR, stable magnetic ...

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化学

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel &#945;-diimine ethylene polymerization catalyst. Initial polymerizations with the catalyst lead to optimized reaction conditions, including catalyst concentration, ethylene pressure and reaction time. Using gas-uptake data for these reactions, a procedure to calculate the initial rate of propagation (kp) is presented. Using the optimized conditions, the ability of the nickel &#945;-diimine polymerization catalyst to undergo chain transfer with diethylzinc (ZnEt2) during ethylene polymerization was investigated. A procedure to assess the ability of the catalyst to undergo chain transfer (from molecular weight and 13C NMR data), calculate the degree of chain transfer, and calculate chain transfer rates (ke) is presented.

A protocol for the high-throughput analysis of polymerization catalyst, chain transfer polymerizations, polyethylene characterization, and reaction kinetic analysis is presented.

乙烯聚合中使用并联电抗器的压力和链转移聚合的动力学分析

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form catalytically active N-Heterocyclic Carbenes (NHCs). Here we have used ILs as precatalysts in the addition of &#945;,&#946;-unsaturated aldehydes to chalcones to form 1,6-ketoesters, incorporating an anti-diphenyl moiety in a highly stereoselective fashion. The reaction has a broad substrate scope and several functional groups and heteroaromatics can be integrated into the ketoester backbone in generally good yields with maintained stereoselectivity. The reaction protocol is robust and scalable. The starting materials are inexpensive and the products can be obtained after simple filtration, avoiding solvent-demanding chromatography. Furthermore, the IL can be recycled up to 5 times without any loss of reactivity. Moreover, the 1,6-ketoester end product is a potent gelator in several hydrocarbon based solvents. The method enables rapid access to and evaluation of a new class of low molecular weight gelators (LMWGs) from recyclable and inexpensive starting materials.

Ionic liquids (ILs) mediate fast, simple and cheap access to 1,6-ketoesters in high diastereoselectivities and good yields. The reaction protocol is robust and the 1,6-ketoesters can be obtained in gram scale after a simple filtration protocol. Moreover, the 1,6-ketoesters are potent gelators in hydrocarbon solvents.

1,6-酮酯高立体选择性合成离子液体介导：三组分反应启用快速进入低分子量胶凝剂的新型类

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form ...

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

合成与盘状磷酸盐锆剥落获取胶体液晶

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

NMR Spectroscopy as a Robust Tool for the Rapid Evaluation of the Lipid Profile of Fish Oil Supplements

The western diet is poor in n-3 fatty acids, therefore the consumption of fish oil supplements is recommended to increase the intake of these essential nutrients. The objective of this work is to demonstrate the qualitative and quantitative analysis of encapsulated fish oil supplements using high-resolution 1H and 13C NMR spectroscopy utilizing two different NMR instruments; a 500 MHz and an 850 MHz instrument. Both proton (1H) and carbon (13C) NMR spectra can be used for the quantitative determination of the major constituents of fish oil supplements. Quantification of the lipids in fish oil supplements is achieved through integration of the appropriate NMR signals in the relevant 1D spectra. Results obtained by 1H and 13C NMR are in good agreement with each other, despite the difference in resolution and sensitivity between the two nuclei and the two instruments. 1H NMR offers a more rapid analysis compared to 13C NMR, as the spectrum can be recorded in less than 1 min, in contrast to 13C NMR analysis, which lasts from 10 min to one hour. The 13C NMR spectrum, however, is much more informative. It can provide quantitative data for a greater number of individual fatty acids and can be used for determining the positional distribution of fatty acids on the glycerol backbone. Both nuclei can provide quantitative information in just one experiment without the need of purification or separation steps. The strength of the magnetic field mostly affects the 1H NMR spectra due to its lower resolution with respect to 13C NMR, however, even lower cost NMR instruments can be efficiently applied as a standard method by the food industry and quality control laboratories.

Here, high-resolution 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy was used as a rapid and reliable tool for quantitative and qualitative analysis of encapsulated fish oil supplements.

核磁共振作为鱼油补充剂的血脂的快速评价一个强大的工具

The western diet is poor in n-3 fatty acids, therefore the consumption of fish oil supplements is recommended to increase the intake of these essential ...

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the average content of fluorinated drugs in their formulated drug product forms: tablets or capsules. This method is specific to fluorinated drugs because it detects only the content of fluorine, avoiding interference from the excipients that lack fluorine. The advantages of measuring the active content of fluorinated drugs using low-field 19F TD-NMR versus high-field 19F solid-state (SS) NMR are the simplicity of the method; the low cost; and the non-destructive nature of the technique, with all samples recoverable in intact forms (e.g., powders, tablets, and capsules), making this technique affordable for any laboratory.
We have tested the method with three fluorinated drug products available on the market - cinacalcet, lansoprazole, and ciprofloxacin - with doses ranging from 15 to 500 mg. The results of the analyses, measured by low-field 19F TD-NMR, supported the reported label claims for the average drug content.
Based on the simplicity and reproducibility of the analysis, we envision this methodology being implemented in any laboratory, including manufacturing plants, as a process analytical technology (PAT) tool in the pharmaceutical industry.

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

A simple and non-destructive technique that measures the average content of drug substances in formulated drug products containing fluorine using low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) is presented here. The technique can be applied to the development and manufacturing of drugs in the pharmaceutical industry.

应用程序和非破坏性19F 时间域核磁共振技术的方法来衡量中含氟药物产品的内容

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the ...

A New Straightforward Method for Lipophilicity (logP) Measurement using 19F NMR Spectroscopy

Fluorination has become an effective tool to optimize physicochemical properties of bioactive compounds. One of the applications of fluorine introduction is to modulate the lipophilicity of the compound. In our group, we are interested in the study of the impact of fluorination on lipophilicity of aliphatic fluorohydrins and fluorinated carbohydrates. These are not UV-active, resulting in a challenging lipophilicity determination. Here, we present a straightforward method for the measurement of lipophilicity of fluorinated compounds by 19F NMR spectroscopy. This method requires no UV-activity. Accurate solute mass, solvent and aliquot volume are also not required to be measured. Using this method, we measured the lipophilicities of a large number of fluorinated alkanols and carbohydrates.

A New Straightforward Method for Lipophilicity logP Measurement using 19F NMR Spectroscopy

A novel and straightforward variation of the shake-flask method was developed for accurate lipophilicity measurement of fluorinated compounds by 19F NMR spectroscopy.

一种利用19f 核磁共振光谱测定脂质性 (日志 p) 的新方法

Fluorination has become an effective tool to optimize physicochemical properties of bioactive compounds. One of the applications of fluorine introduction ...

A Facile Synthetic Method to Obtain Bismuth Oxyiodide Microspheres Highly Functional for the Photocatalytic Processes of Water Depuration

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of materials is highly related to its photocatalytic performance, it is necessary to standardize the synthetic methods in order to obtain the most functional architectures and, thus, the highest photocatalytic efficiency. Here, we report a reliable route to obtain BiOI microspheres via the solvothermal process, using Bi(NO3)3 and potassium iodide (KI) as precursors, and ethylene glycol as a template. The synthesis is standardized in a 150 mL autoclave, at 126 &#176;C for 18 h. This results in 2-3 &#181;m-sized mesoporous microspheres, with a relevant specific surface area (61.3 m2/g). Shortening the reaction times in the synthesis results in amorphous structures, while higher temperatures lead to a slight increase in the porosity of the microspheres, with no effect in the photocatalytic performance. The materials are photo-active under UV-A/visible light irradiation for the degradation of the antibiotic ciprofloxacin in water. This method has demonstrated to be effective in interlaboratory tests, obtaining similar BiOI microspheres in Mexican and Chilean research groups.

This article describes a synthetic method to obtain bismuth oxyiodide microspheres, which are highly functional to perform the photocatalytic removal of organic pollutants, such as ciprofloxacin, in water under UV-A/visible light irradiation.

一种用于水降解光催化过程的高效双氧化二碘微球合成方法

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of ...

Quantitative 31P NMR Analysis of Lignins and Tannins

The development of sustainable biorefinery products is confronted, among others, with the challenge of lignin and tannin valorization. These abundant, renewable aromatic biopolymers have not been widely exploited due to their inherent structural complexity and high degrees of variability and species diversity. The lack of a defined primary structure for these polyphenols is further compounded with complex chemical alterations induced during processing, eventually imparting a large variety of structural features of extreme significance for any further utilization efforts.
Consequently, a protocol for the rapid, simple, and unequivocal identification and quantification of the various functional groups present in natural polyphenols, is a fundamental prerequisite for understanding and accordingly tailor their reactivity and eventual utility.
Quantitative 31P NMR offers the opportunity to rapidly and reliably identify unsubstituted, o-mono substituted, and o-disubstituted phenols, aliphatic OHs, and carboxylic acid moieties in lignins and tannins with broad application potential.
The methodology consists of an in situ quantitative lignin or tannin labeling procedure using a suitable 31P containing probe, followed by the acquisition of a quantitative 31P NMR spectrum in the presence of an internal standard. The high natural abundance of the 31P nucleus allows for small amounts of the sample (~30 mg) and short NMR acquisition times (~30-120 min) with well-resolved 31P signals that are highly dependent on the surrounding chemical environment of the labeled OH groups.

Quantitative 31P NMR Analysis of Lignins and Tannins

31P NMR is a powerful tool for the structural elucidation of polyphenols. This fast, easy, precise, quantitative, and highly reproducible analytical procedure, that allows for the quantification and differentiation of the different types of hydroxy, phenolic, and carboxylic groups in lignins and tannins has now become a routine analytical tool.

利格宁和单宁的定量 31P NMR 分析

The development of sustainable biorefinery products is confronted, among others, with the challenge of lignin and tannin valorization. These abundant, ...

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties dependent on the chemical composition of the resin. In the current work, 3D printed materials are post-functionalized using the 3D printer hardware via a secondary surface-initiated polymerization process, thus providing independent control over the bulk and interfacial material properties. This process begins with preparing liquid resins, which contain a monofunctional monomer, a crosslinking multifunctional monomer, a photochemically labile species that enables initiation of polymerization, and critically, a thiocarbonylthio compound which facilitates reversible addition-fragmentation chain transfer (RAFT) polymerization. The thiocarbonylthio compound, known commonly as a RAFT agent, mediates the chain growth polymerization process and provides polymeric materials with more homogeneous network structures. The liquid resin is cured in a layer-by-layer fashion using a commercially available digital light processing 3D printer to give three-dimensional materials having spatially controlled geometries. The initial resin is removed and replaced with a new mixture containing functional monomers and photoinitiating species. The 3D printed material is then exposed to light from the 3D printer in the presence of the new functional monomer mixture. This allows photoinduced surface-initiated polymerization to occur from the latent RAFT agent groups on the surface of the 3D printed material. Given the chemical flexibility of both resins, this process allows a wide range of 3D printed materials to be produced with tailorable bulk and interfacial properties.

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

The present protocol describes the digital light processing-based 3D printing of polymeric materials using type I photoinitiated reversible addition-fragmentation chain transfer polymerization and the subsequent in situ material post-functionalization via surface-mediated polymerization. Photoinduced 3D printing provides materials with independently tailored and spatially controlled bulk and interfacial properties.

通过I型光引发可逆加成-碎片链转移聚合进行3D打印和原位表面改性

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties ...