Bonding and Substituent Effects in Electron-Rich Mononuclear Ruthenium σ-Arylacetylides of the Formula [(η2-dppe)(η5-C5Me5)Ru(C⋮C)-1,4-(C6H4)X][PF6]n (n = 0, 1; X = NO2, CN, F, H, OMe, NH2)
摘要:
This study reports the isolation and the structural (X-ray), UV-vis, and NMR characterization of a series of electron-rich Ru(II) acetylide complexes of the formula (eta(2)-dppe)(eta(5)-C5Me5)Ru(C equivalent to X)-1,4-(C6H4)X (1a-f; X = NO2, CN, F, H, OMe, NH2) and (eta(2)-dppe)(eta(5)-C5Me5)Ru(C equivalent to C)-1,3-(C6H4)F (1c-m), as well as the spectroscopic (near-IR and ESR) in situ characterization of the corresponding elusive Ru(III) radical cations. The spectroscopic data are discussed in connection with DFT computations, and a consistent picture of the electronic structure of these Ru(11) and Ru(111) acetylide complexes is proposed. Notably, the strong reactivity of the Ru(Ill) radicals evidenced in this contribution constitutes a major difference with the relative stability of the known iron analogues.
一种方便的修改对于络合物[M(C的制备所建立的合成路线CR)(DPPE)的Cp'](M =铁,钌; CP'=η 5 -C 5 H ^ 5(CP),η 5 -C 5 Me 5(Cp *); R = C 6 H 5,C 6 H 4 - p -OMe,C 6 H 4 - p -NO 2,t Bu)和[Ru(C CR)(PPh 3)2 Cp ]从相应的[的MC1(PP)的Cp']配合物和炔烃HC CR经由描述了中间体亚乙烯基。通常从反应混合物中直接以高质量结晶样品的形式获得配合物。与先前的研究一致,铁络合物主要经历了以金属为中心的氧化,而乙炔配体更多地参与了与钌类似物有关的氧化过程。氧化还原性质的分析和光谱电化学研究表明,在Fe和Ru系列中,Cp与Cp *衍生物的总电子结构存在有限的差异。