- Electronically Strongly Coupled Divinylheterocyclic-Bridged Diruthenium Complexes
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Complexes [{Ru(CO)Cl(PiPr3)2}2(μ-2,5-(CH=CH)2-cC4H2E] (E=NR; R=C6H4-4-NMe2 (10a), C6H4-4-OMe (10b), C6H4-4-Me (10c), C6H5 (10d), C6H4-4-CO2Et (10e), C6H4-4-NO2 (10f), C6H3-3,5-(CF3)2 (10g), CH3 (11); E=O (12), S (13)) are discussed. The solid state structures of four alkynes and two complexes are reported. (Spectro)electrochemical studies show a moderate influence of the nature of the heteroatom and the electron-donating or -withdrawing substituents R in 10a-g on the electrochemical and spectroscopic properties. The CVs display two consecutive one-electron redox events with ΔE°′=350-495 mV. A linear relationship between ΔE°′ and the σp Hammett constant for 10a-f was found. IR, UV/Vis/NIR and EPR studies for 10+-13+ confirm full charge delocalization over the {Ru}CH=CH-heterocycle-CH=CH{Ru} backbone, classifying them as Class III systems according to the Robin and Day classification. DFT-optimized structures of the neutral complexes agree well with the experimental ones and provide insight into the structural consequences of stepwise oxidations.
- Pfaff, Ulrike,Hildebrandt, Alexander,Korb, Marcus,O?wald, Steffen,Linseis, Michael,Schreiter, Katja,Spange, Stefan,Winter, Rainer F.,Lang, Heinrich
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- Improved Buchwald-Hartwig Amination by the Use of Lipids and Lipid Impurities
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The development of green Buchwald-Hartwig aminations has long been considered challenging, due to the high sensitivity of the reaction to the environment. Here we show that food-grade and waste vegetable oils, triglycerides originating from animals, and natural waxes can serve as excellent green solvents for Buchwald-Hartwig amination. We further demonstrate that amphiphiles and trace ingredients present in triglycerides as additives have a decisive effect on the yields of Buchwald-Hartwig aminations.
- Bayer, Annette,Gevorgyan, Ashot,Hopmann, Kathrin H.
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(2021/11/12)
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