Anjali Kaiprathu, Christopher Jayaraj, Sakthivel Ayyamperumal
Inorganic Materials & Heterogeneous Catalysis Laboratory, Department of Chemistry, School of Physical Sciences, Central University of Kerala Kasaragod, Sabarmati Building, Tejawini Hills, Kasaragod 671316, India.
Indian Oil Corporation Limited, R&D Centre, Faridabad 121007, India.
ACS Omega. 2019 Aug 8;4(8):13454-13464. doi: 10.1021/acsomega.9b01741. eCollection 2019 Aug 20.
Ruthenium-containing tetraphenylporphyrin (Ru-TPP) molecule was prepared, and the structural elucidation was confirmed using H nuclear magnetic resonance (NMR), CHN, and mass spectral analyses. The incorporation of ruthenium ion into the cavities of the macromolecule was confirmed from the disappearance of the H NMR signal, characteristic of the N-H bond (-2.72 ppm in TPP). The CHN and mass spectral analyses of the ligand and metallomacromolecules are consistent with the theoretically calculated values. The homogeneous Ru-TPP macromolecule is grafted on the surface of aminosilane-, diaminosilane-, and iodosilane-functionalized SBA-15 molecular sieves. The successful grafting of Ru-TPP on functionalized mesoporous molecular sieve materials was evident from low-angle powder X-ray diffraction, C magic angle spinning NMR, and scanning electron microscopy-energy-dispersive X-ray analyses. The resultant homogeneous and heterogenized Ru-TPP catalysts were used for the utilization of carbon dioxide (CO) under moderate reaction conditions. The homogeneous Ru-TPP catalyst showed first-order kinetics with respect to epoxide with the exclusive formation of cyclic carbonate (about 98%) and an activation energy of 16.07 kg/mol, which is much lower than some of the reported catalysts. Ru-TPP grafted on aminosilane- and iodosilane-functionalized materials showed better catalytic activity (above 90% conversion and 83-96% cyclic carbonate selectivity) and reusability for the chosen reaction.
制备了含钌的四苯基卟啉（Ru-TPP）分子，并通过氢核磁共振（NMR）、CHN和质谱分析对其结构进行了确认。从表征N-H键的氢核磁共振信号（TPP中为-2.72 ppm）消失，证实了钌离子已掺入大分子的空穴中。配体和金属大分子的CHN和质谱分析结果与理论计算值一致。将均相的Ru-TPP大分子接枝到氨基硅烷、二氨基硅烷和碘代硅烷功能化的SBA-15分子筛表面。从低角度粉末X射线衍射、C魔角旋转NMR和扫描电子显微镜-能量色散X射线分析可以明显看出Ru-TPP成功接枝到功能化介孔分子筛材料上。所得的均相和多相Ru-TPP催化剂用于在温和反应条件下利用二氧化碳（CO）。均相Ru-TPP催化剂对环氧化物表现出一级动力学，专一形成环状碳酸酯（约98%），活化能为16.07 kg/mol，远低于一些已报道的催化剂。接枝到氨基硅烷和碘代硅烷功能化材料上的Ru-TPP对所选反应表现出更好的催化活性（转化率高于90%，环状碳酸酯选择性为83 - 96%）和可重复使用性。
