Zhang Hong, Wu Liqiong, Lin Ran, Zhao Qianyi, He Guomei, Yang Fangzu, Wen Ting Bin, Xia Haiping
Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, P.R. China.
Chemistry. 2009;15(14):3546-59. doi: 10.1002/chem.200801774.
Treatment of [OsCl(2)(PPh(3))(3)] with HC[triple bond]CCH(OH)C[triple bond]CH/PPh(3) produces the osmabenzene [Os{CHC(PPh(3))CHC(PPh(3))CH}Cl(2)(PPh(3))(2)][OH] (2), which is air stable in both solution and solid state. The key intermediate of the one-pot reaction, [OsCl(2){CH=C(PPh(3))CH(OH)C[triple bond]CH}(PPh(3))(2)] (3), and the related complex [Os(NCS)(2){CHC(PPh(3))CH(OH)C[triple bond]CH}(PPh(3))(2)] (7) have been isolated and characterized, further supporting the proposed mechanisms for the reaction. Reactions of 3 with PPh(3), NaI, and NaSCN give osmabenzene 2, iodo-substituted osmabenzene [Os{CHC(PPh(3))CHCICH}I(2)(PPh(3))(2)] (4), and thiocyanato-substituted osmabenzene [Os{CHC(PPh(3))CHC(SCN)CH}(NCS)(2)(PPh(3))(2)] (5) respectively. Similarly, reaction of [OsBr(2)(PPh(3))(3)] with HC[triple bond]CCH(OH)C[triple bond] CH in THF produces [OsBr(2){CH=C(PPh(3))CH(OH)C[triple bond]CH}(PPh(3))(2)] (9), which reacts with PPh(3)/Bu(4)NBr to give osmabenzene [Os{CHC(PPh(3))CHC(PPh(3))CH}Br(2)(PPh(3))(2)]Br (10). Ligand substitution reactions of 2 produce a series of new stable osmabenzenes 11-17. An electrochemical study shows that osmabenzenes 2, 12, and 14-17 have interesting different electrochemical properties due to the different co-ligand. The oxidation potentials of complexes 2, 12, 16, and 17 with Cl, NCS, and N(CN)(2) ligands gradually positively shift in the sequence of Cl<NCS<N(CN)(2). Among the six compounds, only 12 and 17 undergo a well-behaved, nearly reversible and a quasi-reversible reduction process, respectively, indicating that two NCS or N(CN)(2) ligands contribute to the stabilization of their reduced states.
用HC≡CCH(OH)C≡CH/PPh₃处理[OsCl₂(PPh₃)₃]可生成锇苯[Os{CHC(PPh₃)CHC(PPh₃)CH}Cl₂(PPh₃)₂][OH] (2)，其在溶液和固态中均对空气稳定。一锅法反应的关键中间体[OsCl₂{CH=C(PPh₃)CH(OH)C≡CH}(PPh₃)₂] (3)以及相关配合物[Os(NCS)₂{CHC(PPh₃)CH(OH)C≡CH}(PPh₃)₂] (7)已被分离和表征，进一步支持了所提出的反应机理。3与PPh₃、NaI和NaSCN反应分别生成锇苯2、碘取代的锇苯[Os{CHC(PPh₃)CHCICH}I₂(PPh₃)₂] (4)和硫氰酸根取代的锇苯[Os{CHC(PPh₃)CHC(SCN)CH}(NCS)₂(PPh₃)₂] (5)。类似地，[OsBr₂(PPh₃)₃]与HC≡CCH(OH)C≡CH在THF中反应生成[OsBr₂{CH=C(PPh₃)CH(OH)C≡CH}(PPh₃)₂] (9)，其与PPh₃/Bu₄NBr反应生成锇苯[Os{CHC(PPh₃)CHC(PPh₃)CH}Br₂(PPh₃)₂]Br (10)。2的配体取代反应生成了一系列新的稳定锇苯11 - 17。电化学研究表明，由于共配体不同，锇苯2、12和14 - 17具有有趣的不同电化学性质。含Cl、NCS和N(CN)₂配体的配合物(2、12、16和17)的氧化电位按Cl<NCS<N(CN)₂的顺序逐渐正向移动。在这六种化合物中，只有12和17分别经历了行为良好、近乎可逆和准可逆的还原过程，表明两个NCS或N(CN)₂配体有助于稳定它们的还原态。
