High-Density Covalent Grafting of Spin-Active Molecular Moieties to Diamond Surfaces
High-Density Covalent Grafting of Spin-Active Molecular Moieties to Diamond Surfaces
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DOI：
10.1021/acs.langmuir.1c01425
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发表时间：
2021-07-19
期刊：
影响因子：
3.9
通讯作者：
Hamers, Robert J.
中科院分区：
文献类型：
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作者：
Bachman, Benjamin F.;Jones, Zachary R.;Hamers, Robert J.
利用TEMPO和其他表面顺磁物质对金刚石表面进行功能化，是利用硅空位（SiV）和氮空位（NV）中心等浅量子色缺陷实现新型化学检测方案的一种方法。然而，由于缺乏将自由基连接到金刚石表面的高质量表面功能化方案，先前基于量子化学传感的方法受到了阻碍。在这里，我们展示了一种高度控制的方法，通过不同长度的全碳系链将金刚石表面与羧酸基团功能化，然后通过共价化学产生高质量的tempo修饰表面。我们的研究估计4-氨基- tempo在纳米金刚石上的表面密度约为1.4分子nm(-2)（随分子连接剂长度的变化而变化），在平面金刚石上的表面密度约为3.3分子nm（-2）。这些值高于以前使用其他功能化方法报告的值。利用纳米金刚石的ζ电位来跟踪反应过程，并阐明了乙烯基和羧酸基与表面自由基之间反应的区域选择性。
Functionalization of diamond surfaces with TEMPO and other surface paramagnetic species represents one approach to the implementation of novel chemical detection schemes that make use of shallow quantum color defects such as silicon-vacancy (SiV) and nitrogen-vacancy (NV) centers. Yet, prior approaches to quantum-based chemical sensing have been hampered by the absence of high-quality surface functionalization schemes for linking radicals to diamond surfaces. Here, we demonstrate a highly controlled approach to the functionalization of diamond surfaces with carboxylic acid groups via all-carbon tethers of different lengths, followed by covalent chemistry to yield high-quality, TEMPO-modified surfaces. Our studies yield estimated surface densities of 4-amino-TEMPO of approximately 1.4 molecules nm(-2) on nanodiamond (varying with molecular linker length) and 3.3 molecules nm(-2) on planar diamond. These values are higher than those reported previously using other functionalization methods. The zeta-potential of nanodiamonds was used to track reaction progress and elucidate the regioselectivity of the reaction between ethenyl and carboxylate groups and surface radicals.