Bis(acetylacetonato)ruthenium(II) complexes containing bulky tertiary phosphines.: Formation and redox behaviour of Ru(acac)2 (PR3) (R = iPr, Cy) complexes with ethene, carbon monoxide, and bridging dinitrogen
Bis(acetylacetonato)ruthenium(II) complexes containing bulky tertiary phosphines.: Formation and redox behaviour of Ru(acac)2 (PR3) (R = iPr, Cy) complexes with ethene, carbon monoxide, and bridging dinitrogen
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DOI：
10.1016/j.ica.2004.07.062
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发表时间：
2005-03-15
影响因子：
2.8
通讯作者：
Willis, AC
中科院分区：
文献类型：
--
作者：
Bennett, MA;Byrnes, MJ;Willis, AC
顺式-[Ru(acac)(2)(eta(2)-C8H14)(2)] (1) (acac = 乙酰丙酮)与两当量的(PPr3)-Pr-i在THF中在-25℃下反应得到反式-[Ru(acac)(2)((PPr3)-Pr-i)(2)], trans-3，在室温下迅速异构化为cis-3 温度。难溶性络合物 [Ru(acac)(2)(PCy3)(2)] (4) 类似地从顺式-[Ru(acac)(2)(eta-C2H4)(2)] (2) 和 PCy3 中分离出来，根据 NMR 数据，似乎以顺式构型存在于溶液中，但单晶的 X 射线衍射研究表明存在反式 4。在苯或甲苯中，2 与 PPr3 或 PCy3 反应，仅生成顺式-[Ru(acac)(2)(eta(2)-C2H4)(L)] [L = (PPr3)-Pr-i (5), PCy3 (6)]，而在 THF 物质中，被认为是带有顶端 L 的方锥体 [Ru(acac)(2)L]，或相应的 THF 加合物，可以通过 P-31 NMR 光谱检测。络合物 3-6 与 CO (1 bar) 反应，得到反式-[Ru(acac)(2)(CO)(L)] [L = (PPr3)-Pr-i (trans-8), PCy3 (trans-9)]，其在回流苯中不可逆地转化为顺式异构体。配合物 5 从工业级二氢中清除痕量二氮，得到桥联二氮配合物 cis-[{Ru(acac)(2)((PPr3)-Pr-i)} (2)(mu-N-2)] (10)。 cis-3、trans-4、5、6 和 10(.)C(6)H(14) 的结构已通过单晶 X 射线衍射确定。配合物 trans- 和 cis-3, 5, 6, cis-8, 以及 trans- 和 cis-9 通过循环伏安法在 CH2Cl2 中于 -50 摄氏度下显示出完全可逆的单电子氧化，E-1/2(Ru3+/2+) 值跨度为 -0.14 至 +0.92 V（相对于 Ag/AgCl），而对于亚乙烯基配合物 [Ru(acac)(2) (C=CHR)((PPr3)-Pr-i)] [R = SiMe3 (11), Ph (12)] 该过程分别在+0.75 V 和+0.62 V 电位下不可逆。电势趋势反映了配体预期 pi 受体能力的顺序：(PPr3)-Pr-i, PCy3 < CH-2(4) < C=CHR < CO。在 -50 摄氏度下观察到热不稳定、产电额定 Ru-III-乙烯阳离子 6(+) 的 UV-Vis 光谱。mu-二氮配合物 10 的循环伏安法显示 两个完全可逆的过程，在 -50 摄氏度、+0.30 和 +0.90 V（相对于 Ag/AgCl）的 CH2Cl2 中，对应于 10+ (Ru-II.III) 和 10(2+) (Ru-II,Ru-III) 的形成。前者在 -50 摄氏度下以电化学方式产生，在近红外光谱中显示出约 100°C 处的谱带。 8900 cm(-1)（w(1/2)约3700 cm-1）与价离域系统的存在一致。 223 K 时平衡 10+ 10(2+) 可逆箭头 2 10(+) 的比例常数估计为 10(1,3,6)。 (c) 2004 Elsevier B.V. 保留所有权利。
Reaction of cis-[Ru(acac)(2)(eta(2)-C8H14)(2)] (1) (acac = acetylacetonato) with two equivalents of (PPr3)-Pr-i in THF at -25 degrees C gives trans-[Ru(acac)(2)((PPr3)-Pr-i)(2)], trans-3, which rapidly isomerizes to cis-3 at room temperature. The poorly soluble complex [Ru(acac)(2)(PCy3)(2)] (4), which is isolated similarly from cis-[Ru(acac)(2)(eta-C2H4)(2)] (2) and PCy3, appears to exist in the cis-configuration in solution according to NMR data, although an X-ray diffraction study of a single crystal shows the presence of trans-4. In benzene or toluene 2 reacts with PPr3 or PCy3 to give exclusively cis-[Ru(acac)(2)(eta(2)-C2H4)(L)] [L = (PPr3)-Pr-i (5), PCy3 (6)], whereas in THF species believed to be either square pyramidal [Ru(acac)(2)L], with apical L, or the corresponding THF adducts, can be detected by P-31 NMR spectroscopy. Complexes 3-6 react with CO (1 bar) giving trans-[Ru(acac)(2)(CO)(L)] [L = (PPr3)-Pr-i (trans-8), PCy3 (trans-9)], which are converted irreversibly into the cis-isomers in refluxing benzene. Complex 5 scavenges traces of dinitrogen from industrial grade dihydrogen giving a bridging dinitrogen complex, cis-[{Ru(acac)(2)((PPr3)-Pr-i)} (2)(mu-N-2)] (10). The structures of cis-3, trans-4, 5, 6 and 10(.)C(6)H(14) have been determined by single-crystal X-ray diffraction. Complexes trans- and cis-3, 5, 6, cis-8, and trans- and cis-9 each show fully reversible one-electron oxidation by cyclic voltammetry in CH2Cl2 at -50 degrees C with E-1/2(Ru3+/2+) values spanning -0.14 to +0.92 V (versus Ag/AgCl), whereas for the vinylidene complexes [Ru(acac)(2) (C=CHR)((PPr3)-Pr-i)] [R = SiMe3 (11), Ph (12)] the process is irreversible at potentials of +0.75 and +0.62 V, respectively. The trend in potentials reflects the order of expected pi-acceptor ability of the ligands: (PPr3)-Pr-i, PCy3 < C H-2(4) < C=CHR < CO. The UV-Vis spectrum of the thermally unstable, electrogene rated Ru-III-ethene cation 6(+) has been observed at -50 degrees C. Cyclic voltammetry of the mu-dinitrogen complex 10 shows two, fully reversible processes in CH2Cl2 at -50 degrees C at +0.30 and +0.90 V (versus Ag/AgCl) corresponding to the formation of 10+ (Ru-II.III) and 10(2+) (Ru-II,Ru-III). The former, generated electrochemically at -50 degrees C, shows a band in the near IR at ca. 8900 cm(-1) (w(1/2) ca. 3700 cm-1) consistent with the presence of a valence delocalized system. The comproportionation constant for the equilibrium 10+ 10(2+) reversible arrow 2 10(+) at 223 K is estimated as 10(1,3,6). (c) 2004 Elsevier B.V. All rights reserved.