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Applications of Sensors to Physical Measurements
Published in Robert B. Northrop, Introduction to Instrumentation and Measurements, 2018
Suslick et al. (1999) illustrated sharp MBSL line spectra from nonaqueous silicone oil containing metal carbonyl compounds such as Fe(CO)5, Cr(CO)6,W(CO)6, and Mo(CO)6. The MBSL emission lines for these compounds were almost identical to the emission lines when the compound was burned in a flame at ca. 5000 K. MBSL in pure water has been shown to give a strong, broad emission line peak at 310 nm from an excited state of –OH. When metal salts are dissolved in water or alcohol, the MBSL spectra show the metal line spectra.
Onion-Like Inorganic Fullerenes from a Polyhedral Perspective
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Ch. Chang, A. B. C. Patzer, D. Sülzle, H. Bauer
The review will be mainly concerned with the geometric and structural properties of representative inorganic cage species even though not all of them could be strictly classified as fullerenes. It is their polyhedral shape usually accompanied with high symmetry and high sphericity that gives these molecular systems their beautiful aesthetic look. It is intriguing how polyhedral structures appear at different dimensional scales, from electron densities at the subatomic level up to everyday objects. Starting at the subatomic level, electron densities for different electron configurations in transition metal clusters may show cubic, octahedral, or tetrahedral shapes (Bouguerra et al. 2007; Jones, Eberhart, and Clougherty 2007). Also, representations of the density of d electrons around a metal atom in [Cr(CO)6] (Macchi and Sironi 2003), of its Laplacian in [Fe2(CO)9] or in [Mn(CO)6]+ (Bo, Sarasa, and Poblet 1993; Bader, Matta, and Cortés-Guzmán 2004), and of the electron localization function in [Re2(CO)10] reveal cubic shapes (Kohout, Wagner, and Grin 2002). At the polyatomic level, the coordination polyhedra around metal atoms have diameters of a few tenths of a nanometer, while typical metal clusters can approach 1 nm and large clusters can reach up to 2 nm in diameter. Very large multi-polyhedral systems assembled through bridging ligands can reach sizes of about 2–3 nm, as in Pd144 and Mo132 (Tran, Powell, and Dahl 2000; Müller et al. 1999). Icosahedral quasi-crystals, nanoclusters and nanoparticles are in the 10–20 nm size range, where we can also find a single-stranded DNA molecule folded into a hollow octahedron with a diameter of approximately 22 nm, as well as other DNA polyhedra including the tetrahedron, the cube, and the truncated octahedron reported by (Shih, Quispe, and Joyce 2004). The capsids of viruses may reach a size in an order of magnitude larger (between 10 and 100 nm), among which structures of the icosahedral symmetry have been widely reproduced (Twarock 2006).
Palladium imine-pyridine-imine complex immobilized on graphene oxide as a recyclable catalyst for the carbonylative homo-coupling of aryl halides
Published in Journal of Coordination Chemistry, 2021
Mahsa Niakan, Zahra Asadi, Fatemeh Khosrozadeh
A nanohybride material was prepared by immobilization of a NNN pincer ligand on the organo-functionalized surface of GO and subsequent complexation with Pd(OAc)2. The prepared nanohybride was a highly active and stable heterogeneous catalyst for carbonylative homo-coupling of aryl iodides and bromides using Cr(CO)6 as the carbon monoxide source. To see viability and scope of the present methodology, a variety of aryl iodides and bromides were used and in all cases the desired symmetrical diaryl ketones were obtained in good to excellent yields. The catalyst also revealed outstanding stability and recyclability, could be readily recovered by filtration and reused for five cycles without decrease of its catalytic efficiency.