Vibrational structure analysis of cobalt fluoro-porphyrin surface coatings on gallium phosphide
Vibrational structure analysis of cobalt fluoro-porphyrin surface coatings on gallium phosphide
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DOI：
10.1142/s1088424618500906
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发表时间：
2018-06
影响因子：
1.5
通讯作者：
D. Khusnutdinova;Anna M. Beiler;Brian L. Wadsworth;Sylvia Nanyangwe;G. Moore
中科院分区：
文献类型：
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作者：
D. Khusnutdinova;Anna M. Beiler;Brian L. Wadsworth;Sylvia Nanyangwe;G. Moore
掠射角衰减全反射傅立叶变换红外 (GATR-FTIR) 光谱用于表征化学改性的磷化镓 (GaP) 表面，其中含有接枝的钴 (II) 卟啉，并在中间位置安装有 3-氟苯基取代基。在这些杂化结构中，卟啉表面附着是通过使用两步法来实现的，该方法涉及将钴氟卟啉金属中心配位到最初施加的薄膜聚吡啶表面涂层上的氮位点，或者通过使用带有共价键合的4-乙烯基苯基表面附着基团的钴氟卟啉前体的直接修饰策略来实现。 【公式：见正文】-位置。两种表面附着化学都利用紫外线诱导的烯烃固定，但导致接枝卟啉单元及其相关振动光谱的不同结构连接性。特别是，通过与聚合物界面配位制备的样品中金属卟啉组分的面内变形振动频率的特征在于，与使用一步附着法制备的金属卟啉修饰表面上测量的频率相比，八波数向更高频率移动。聚合物结构中更刚性的环结构与卟啉钴中心与表面接枝上的吡啶基氮位点的配位一致。这些结果表明，GATR-FTIR 光谱法可以作为一种灵敏的工具来表征卟啉修饰的表面，其吸收信号接近许多常见光谱技术的检测限。
Grazing angle attenuated total reflectance Fourier transform infrared (GATR–FTIR) spectroscopy is used to characterize chemically modified gallium phosphide (GaP) surfaces containing grafted cobalt(II) porphyrins with 3-fluorophenyl substituents installed at the meso-positions. In these hybrid constructs, porphyrin surface attachment is achieved using either a two-step method involving coordination of cobalt fluoro-porphyrin metal centers to nitrogen sites on an initially applied thin-film polypyridyl surface coating, or via a direct modification strategy using a cobalt fluoro-porphyrin precursor bearing a covalently bonded 4-vinylphenyl surface attachment group at a [Formula: see text]-position. Both surface-attachment chemistries leverage the UV-induced immobilization of alkenes but result in distinct structural connectivities of the grafted porphyrin units and their associated vibrational spectra. In particular, the in-plane deformation vibrational frequency of metalloporphyrin components in samples prepared via coordination to the polymeric interface is characterized by an eight wavenumber shift to higher frequencies compared to that measured on metalloporphyrin-modified surfaces prepared using the one-step attachment method. The more rigid ring structure in the polymeric architecture is consistent with coordination of porphyrin cobalt centers to pyridyl-nitrogen sites on the surface graft. These results demonstrate the use of GATR–FTIR spectroscopy as a sensitive tool for characterizing porphyrin-modified surfaces with absorption signals that are close to the detection limits of many common spectroscopic techniques.