Bis- and Tris(dimethylgallyl)benzenes: Synthesis, Solid-State Structures, and Redistribution Reactions

Jutzi P, Izundu J, Sielemann H, Neumann B, Stammler H-G. Bis- and Tris(dimethylgallyl)benzenes: Synthesis, Solid-State Structures, and Redistribution Reactions. ORGANOMETALLICS. 2009;28(8):2619-2624.Benzene derivatives containing dimethylgallyl substituents in 1,3-(compounds 5 and 6), 1,4-(compound 9), and 1,3,5-position (compound 1.2) were prepared by reaction of the corresponding chloromercuriobertzenes with an excess of trimethylgallium at higher temperatures. These compounds decompose in solution at room temperature and in the solid state upon mild heating with elimination of trimethylgallium to give oligomeric condensation products of unknown detailed composition. These condensation products can be transformed back into the starting compounds by treatment with an excess of trimethylgallium at higher temperatures. Highly air-sensitive crystals of 5, 6, 9, and 12 suitable for an X-ray analysis are obtained from trimethylgallium as solvent. The X-ray crystallographic studies revealed the presence of higher coordinate gallium atoms, which lead to the fort-nation of strand- or sheet-like polymers. A trigonal-bipyramidal coordination sphere is observed for the gallium atoms in 9. A distorted tetrahedral coordination is found for the gallium atoms in 5, 6, and 12. The latter compounds possess asymmetric aryl-dimethylgallyl bridging units

Experimental and DFT study on the indiummediated synthesis of benzophenones via arylstannanes

Experimental results of the solvent-free, indium-promoted reaction of aroyl chlorides with arylstannanes showed a narrow scope; its efficiency depends both on the extent of methylation in the latter and on the nature, number and position of the substituents in the former. With the purpose of explaining experimental results, a theoretical analysis with DFT methods was performed for a set of selected cases.Fil: Lo Fiego, Marcos Jacinto. Universidad Nacional del Sur. Departamento de Quimica. Instituto de Invest.en Quimica Organica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; ArgentinaFil: Dorn, Viviana B.. Universidad Nacional del Sur. Departamento de Quimica. Instituto de Invest.en Quimica Organica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; ArgentinaFil: Badajoz, Mercedes A.. Universidad Nacional del Sur. Departamento de Quimica. Instituto de Invest.en Quimica Organica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; ArgentinaFil: Lockhart, Maria T.. Universidad Nacional del Sur. Departamento de Quimica. Instituto de Invest.en Quimica Organica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; ArgentinaFil: Chopa, Alicia B.. Universidad Nacional del Sur. Departamento de Quimica. Instituto de Invest.en Quimica Organica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentin

Synthesis and Structural Characterization of Water-Soluble Gold(I) N‑Heterocyclic Carbene Complexes. An X‑ray Absorption Fine Structure Spectroscopy (XAFS) Study

Water-soluble gold­(I) N-heterocyclic carbene complexes were synthesized and characterized using X-ray absorption spectroscopy (XAFS) in combination with traditional analytical techniques such as NMR, mass spectrometry, and UV–vis spectroscopy. XANES and EXAFS regions are sensitive to coordination number, ligand electronic structure, and distance around the metal center, providing information on the oxidation state and bonding structure of gold, which allows discrimination between mono- and bis-carbene species. Preliminary results showed that the catalysts are active in the hydration of terminal alkynes in aqueous media; in addition, they are highly recyclable