59073-99-3Relevant articles and documents
Dicopper Alkyl Complexes: Synthesis, Structure, and Unexpected Persistence
Ziegler, Micah S.,Torquato, Nicole A.,Levine, Daniel S.,Nicolay, Amélie,Celik, Hasan,Tilley, T. Don
, p. 2807 - 2823 (2018)
Cationic μ-alkyl dicopper complexes [Cu2(μ-n1: n 1-R)DPFN]NTf2 (R = CH3, CH2CH3, CH2C(CH3)3; DPFN = 2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine NTf2- = N(SO2CF3)2-) were synthesized by treatment of the acetonitrile-bridged dicopper complex [Cu2(μ- n 1: n 1-NCCH3)DPFN](NTf2)2 with LiR or MgR2. Structural characterization by X-ray crystallography and NMR spectroscopy revealed that the alkyl ligands symmetrically bridge the two copper centers, and the complexes persist in room-temperature solution. Notably, the μ-methyl complex showed less than 20% decomposition after 34 days in room-temperature THF solution. Treatment of the μ-methyl complex with acids allows installation of a range of monoanionic bridging ligands. However, surprisingly insertion into the dicopper-carbon bond was not observed upon addition of a variety of reagents, suggesting that these complexes exhibit a fundamentally new reactivity profile for alkylcopper species. Electrochemical characterization revealed oxidation-reduction events that evidence putative mixed-valence dicopper alkyl complexes. Computational studies suggest that the dicopper-carbon bonds are highly covalent, possibly explaining their remarkable stability.
Organoboranes. 40. A simple preparation of borinic esters from organolithium reagents and selected boronic esters
Brown, Herbert C.,Cole, Thomas E.,Srebnik, Morris
, p. 1788 - 1792 (2008/10/08)
Monoorganyldiisopropoxyboranes, RB(O-i-Pr)2, react cleanly at -78 °C with 1 equiv of organolithium compounds, R′Li, to form the corresponding complexes of the borinic acid esters, LiRR′B(O-i-Pr)2. Treatment of these complexes with an equivalent of anhydrous hydrogen chloride in ethyl ether liberates the borinic esters, RR′BO-i-Pr, and isopropyl alcohol, usually readily separated by distillation. Alternatively, treatment of the complexes with 1 mol of an appropriate acid chloride liberates the borinic esters, RR′BO-i-Pr, and an isopropyl ester, RCO2-i-Pr. By careful selection of the acid chloride, these two products can be easily separated by distillation. A careful examination of the reaction of other boronic esters in this reaction revealed that the boronic esters of 1,3-propanediol forms the 1:1 complex cleanly on reaction with organolithium compounds at -78 °C. (Formula Presented) Treatment of these ate complexes either with hydrogen chloride in ether or with an appropriate acid chloride provides the pure borinic ester. Consequently, simple rational procedures are now available for the synthesis in high purities and yields of either boronic or borinic acids and esters, either through hydroboration or through the use of organolithium compounds.
