Zywitzki Dennis, Taffa Dereje H, Lamkowski Laura, Winter Manuela, Rogalla Detlef, Wark Michael, Devi Anjana
Inorganic Materials Chemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801 Bochum, Germany.
Chemical Technology 1, Institute of Chemistry, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany.
Inorg Chem. 2020 Jul 20;59(14):10059-10070. doi: 10.1021/acs.inorgchem.0c01204. Epub 2020 Jun 26.
Nickel-based nanostructured materials have gained widespread attention, particularly for energy-related applications. Employing chemical vapor deposition (CVD) for NiO necessitates suitable nickel precursors that are volatile and stable. Herein, we report the synthesis and characterization of a series of new nickel β-ketoiminato complexes with different aliphatic and etheric side chain substitutions, namely, bis(4-(isopropylamino)-pent-3-en-2-onato)nickel(II) ([Ni(ipki)], ), bis(4-(2-methoxyethylamino)pent-3-en-2-onato)nickel(II) ([Ni(meki)], ), bis(4-(2-ethoxyethylamino)pent-3-en-2-onato)nickel(II) ([Ni(eeki)], ), bis(4-(3-methoxy-propylamino)-pent-3-en-2-onato)nickel(II) ([Ni(mpki)], ), and bis(4-(3-ethoxypropylamino)pent-3-en-2-onato)nickel(II) ([Ni(epki)], ). These compounds have been thoroughly characterized with regard to their purity and identity by means of nuclear magnetic resonance spectroscopy (NMR) and electron impact mass spectrometry (EI-MS). Contrary to other transition metal β-ketoiminates, the imino side chain strongly influences the structural geometry of the complexes, which was ascertained via single-crystal X-ray diffraction (XRD). As a result, the magnetic momenta of the molecules also differ significantly as evidenced by the magnetic susceptibility measurements employing Evan's NMR method in solution. Thermal analysis revealed the suitability of these compounds as new class of precursors for CVD of Ni containing materials. As a representative precursor, compound was evaluated for the CVD of NiO thin films on Si(100) and conductive glass substrates. The as-deposited nanostructured layers were stoichiometric and phase pure NiO as confirmed by XRD, Rutherford backscattering spectrometry (RBS), and nuclear reaction analysis (NRA). X-ray photoelectron spectroscopy (XPS) indicated the formation of slightly oxygen-rich surfaces. The assessment of NiO films in electrocatalysis revealed promising activity for the oxygen evolution reactions (OER). The current densities of 10 mA cm achieved at overpotentials ranging between 0.48 and 0.52 V highlight the suitability of the new Ni complexes in CVD processes for the fabrication of thin film electrocatalysts.
镍基纳米结构材料已受到广泛关注，尤其是在与能源相关的应用领域。采用化学气相沉积（CVD）法制备氧化镍需要使用挥发性且稳定的合适镍前驱体。在此，我们报告了一系列具有不同脂肪族和醚侧链取代基的新型镍β - 酮亚胺配合物的合成与表征，即双（4 - （异丙基氨基） - 戊 - 3 - 烯 - 2 - 酮基）镍（II）（[Ni（ipki）]）、双（4 - （2 - 甲氧基乙氨基）戊 - 3 - 烯 - 2 - 酮基）镍（II）（[Ni（meki）]）、双（4 - （2 - 乙氧基乙氨基）戊 - 3 - 烯 - 2 - 酮基）镍（II）（[Ni（eeki）]）、双（4 - （3 - 甲氧基丙氨基） - 戊 - 3 - 烯 - 2 - 酮基）镍（II）（[Ni（mpki）]）和双（4 - （3 -
乙氧基丙氨基）戊 - 3 - 烯 - 2 - 酮基）镍（II）（[Ni（epki）]）。通过核磁共振光谱（NMR）和电子轰击质谱（EI - MS）对这些化合物的纯度和结构进行了全面表征。与其他过渡金属β - 酮亚胺不同，亚胺侧链对配合物的结构几何形状有强烈影响，这通过单晶X射线衍射（XRD）得以确定。因此，采用埃文斯核磁共振法在溶液中进行的磁化率测量表明，这些分子的磁矩也有显著差异。热分析表明这些化合物适合作为用于含镍材料化学气相沉积的新型前驱体。作为代表性前驱体，对化合物 在硅（100）和导电玻璃基板上进行了氧化镍薄膜化学气相沉积的评估。X射线衍射（XRD）、卢瑟福背散射光谱（RBS）和核反应分析（NRA）证实，沉积的纳米结构层为化学计量比且相纯的氧化镍。X射线光电子能谱（XPS）表明形成了略富氧的表面。对氧化镍薄膜在电催化方面的评估显示出其在析氧反应（OER）中具有良好的活性。在过电位为0.48至0.52 V范围内实现的10 mA cm²的电流密度突出了新型镍配合物在化学气相沉积过程中用于制造薄膜电催化剂的适用性。
