Inorganic Chemistry II, University of Bayreuth, 95440 Bayreuth, Germany.
Chemistry. 2010 Apr 12;16(14):4231-8. doi: 10.1002/chem.200902836.
A molecular approach to metal-containing ceramics and their application as selective heterogeneous oxidation catalysts is presented. The aminopyridinato copper complex [Cu(2)(Ap(TMS))(2)] (Ap(TMS)H=(4-methylpyridin-2-yl)trimethylsilanylamine) reacts with poly(organosilazanes) via aminopyridine elimination, as shown for the commercially available ceramic precursor HTT 1800. The reaction was studied by (1)H and (13)C NMR spectroscopy. The liberation of the free, protonated ligand Ap(TMS)H is indicative of the copper polycarbosilazane binding. Crosslinking of the copper-modified poly(organosilazane) and subsequent pyrolysis lead to the copper-containing ceramics. The copper is reduced to copper metal during the pyrolysis step up to 1000 degrees C, as observed by solid-state (65)Cu NMR spectroscopy, SEM images, and energy-dispersive spectroscopy (EDS). Powder diffraction experiments verified the presence of crystalline copper. All Cu@SiCN ceramics show catalytic activity towards the oxidation of cycloalkanes using air as oxidant. The selectivity of the reaction increases with increasing copper content. The catalysts are recyclable. This study proves the feasibility of this molecular approach to metal-containing SiCN precursor ceramics by using silylaminopyridinato complexes. Furthermore, the catalytic results confirm the applicability of this new class of metal-containing ceramics as catalysts.
本文提出了一种将含金属陶瓷与作为选择性多相氧化催化剂的应用相结合的方法。氨基吡啶铜配合物[Cu(2)(Ap(TMS))(2)]（Ap(TMS)H = (4-甲基吡啶-2-基)三甲基硅基胺）通过氨基吡啶消除与聚有机硅氮烷反应，如商业上可用的陶瓷前体 HTT 1800 所示。通过（1）H 和（13）C NMR 光谱研究了该反应。游离的、质子化的配体 Ap(TMS)H 的释放表明铜多碳硅氮烷的结合。铜改性聚有机硅氮烷的交联和随后的热解导致含铜陶瓷的形成。在热解步骤中，铜被还原为铜金属，最高可达 1000°C，这可以通过固态（65）Cu NMR 光谱、SEM 图像和能量色散光谱（EDS）观察到。粉末衍射实验证实了结晶铜的存在。所有 Cu@SiCN 陶瓷在使用空气作为氧化剂氧化环烷烃时均显示出催化活性。反应的选择性随铜含量的增加而增加。催化剂可回收利用。这项研究通过使用硅氨基吡啶配合物证明了这种含金属 SiCN 前体陶瓷的分子方法的可行性。此外，催化结果证实了这种新型含金属陶瓷作为催化剂的适用性。
