Coordination Chemistry of Br2InCH2Br: Coordination at the Metal Center

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• 作者：Antonio B. de Carvalho ; Maria A. M. A. de Maurera ; José ; A. Nobrega ; Clovis Peppe ; Martyn A. Brown ; Dennis G. Tuck ; Marcelo Z. Hernandes ; Elson Longo ; and Fabricio R. Sensato
• 刊名：Organometallics
• 出版年：1999
• 出版时间：January 4, 1999
• 年：1999
• 卷：18
• 期：1
• 页码：99 - 105
• 全文大小：110K
• 年卷期：v.18,no.1(January 4, 1999)
• ISSN：1520-6041

文摘

(Bromomethyl)dibromoindium(III), Br₂InCH₂Br, reacts with tetraethylammonium bromide,1,4-dioxane (diox), or tetrahydrofuran (thf) to produce addition compounds of the generalformula Br₂In(L)_nCH₂Br (L = diox, thf, n = 2; L = Br^-, n = 1) in which the ligand is directlyattached to the indium atom. The crystal structure of the ionic derivative [(C₂H₅)₄N][Br₃InCH₂Br] has been solved by X-ray diffraction methods: cell constants a = 10.1710(1) Å, b= 10.1710(1) Å, and c = 35.1745(4) Å, space group P4₁2₁2, V = 3638.78(7) ų, Z = 8, R =0.0519, R_w = 0.0543 for 2374 independent reflections. Quantum mechanical calculations,by the PM3 method, on the parent molecule confirm the postulated strong intramolecularinteraction between the bromomethylic bromine and the metal center. Complete intramolecular bromide transfer gives the tautomeric structure Br₃In^-CH₂⁺. The calculations alsosatisfactorily predict the bond distances and angles in the Br₃InCH₂Br^- anion. Preliminaryinvestigations of the energetics and chemical properties of Br₂In(diox)₂CH₂Br show that themolecule can decompose via elimination of methylene, which can be trapped by a suitablesubstrate (carboxylic acid, iodine), demonstrating the potential use of the compound as amethylene-transfer reagent.