Wong Chun-Yuen, Che Chi-Ming, Chan Michael C W, Han Jie, Leung King-Hung, Phillips David Lee, Wong Kwok-Yin, Zhu Nianyong
Department of Chemistry and HKU-CAS Joint Laboratory on New Materials, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
J Am Chem Soc. 2005 Oct 12;127(40):13997-4007. doi: 10.1021/ja053076+.
The synthesis and spectroscopic properties of trans-[RuL4(C[triple bond]CAr)2] (L4 = two 1,2-bis(dimethylphosphino)ethane, (dmpe)2; 1,5,9,13-tetramethyl-1,5,9,13-tetraazacyclohexadecane, 16-TMC; 1,12-dimethyl-3,4:9,10-dibenzo-1,12-diaza-5,8-dioxacyclopentadecane, N2O2) are described. Investigations into the effects of varying the [RuL4] core, acetylide ligands, and acetylide chain length for the [(-)C[triple bond]C(C6H4C[triple bond]C)(n-1)Ph] and [(-)C[triple bond]C(C6H4)(n-1)Ph] (n = 1-3) series upon the electronic and electrochemical characteristics of trans-RuL4(C[triple bond]CAr)2 are presented. DFT and TD-DFT calculations have been performed on trans-Ru(L')4(C[triple bond]CAr)2 (L' = PH3 and NH3) to examine the metal-acetylide pi-interaction and the nature of the associated electronic transition(s). It was observed that (1) the relationship between the transition energy and 1/n for trans-[Ru(dmpe)2{C[triple bond]C(C6H4C[triple bond]C)(n-1)Ph}2] (n = 1-3) is linear, and (2) the sum of the d(pi)(Ru(II)) --> pi*(C[triple bond]CAr) MLCT energy for trans-[Ru(16-TMC or N2O2)(C[triple bond]CAr)2] and the pi(C[triple bond]CAr) --> d(pi)(Ru(III)) LMCT energy for trans-[Ru(16-TMC or N2O2)(C[triple bond]CAr)2]+ corresponds to the intraligand pi pi* absorption energy for trans-[Ru(16-TMC or N2O2)(C[triple bond]CAr)2]. The crystal structure of trans-[Ru(dmpe)2{C[triple bond]C(C6H4C[triple bond]C)2Ph}2] shows that the two edges of the molecule are separated by 41.7 A. The electrochemical and spectroscopic properties of these complexes can be systematically tuned by modifying L4 and Ar to give E(1/2) values for oxidation of trans-[RuL4(C[triple bond]CAr)2] that span over 870 mV and lambda(max) values of trans-[RuL4(C[triple bond]CAr)2] that range from 19,230 to 31,750 cm(-1). The overall experimental findings suggest that the pi-back-bonding interaction in trans-[RuL4(C[triple bond]CAr)2] is weak and the [RuL4] moiety in these molecules may be considered to be playing a "dopant" role in a linear rigid pi-conjugated rod.
本文描述了反式-[RuL₄(C≡CAr)₂]（L₄ = 两个1,2 - 双（二甲基膦基）乙烷，即(dmpe)₂；1,5,9,13 - 四甲基 - 1,5,9,13 - 四氮杂环十六烷，即16 - TMC；1,12 - 二甲基 - 3,4:9,10 - 二苯并 - 1,12 - 二氮杂 - 5,8 - 二氧杂环十五烷，即N₂O₂）的合成及光谱性质。研究了对于[(-)C≡C(C₆H₄C≡C)(n - 1)Ph]和[(-)C≡C(C₆H₄)(n - 1)Ph]（n = 1 - 3）系列，改变[RuL₄]核、乙炔配体以及乙炔链长度对反式-RuL₄(C≡CAr)₂的电子和电化学特性的影响。对反式-Ru(L')₄(C≡CAr)₂（L' = PH₃和NH₃）进行了密度泛函理论（DFT）和含时密度泛函理论（TD - DFT）计算，以研究金属 - 乙炔π相互作用以及相关电子跃迁的性质。观察到：（1）反式-[Ru(dmpe)₂{C≡C(C₆H₄C≡C)(n - 1)Ph}₂]（n = 1 - 3）的跃迁能量与1/n之间的关系是线性的；（2）反式-[Ru(16 - TMC或N₂O₂)(C≡CAr)₂]的d(π)(Ru(II))→π*(C≡CAr) 金属 - 配体电荷转移（MLCT）能量与反式-[Ru(16 - TMC或N₂O₂)(C≡CAr)₂]+的π(C≡CAr)→d(π)(Ru(III)) 配体 - 金属电荷转移（LMCT）能量之和对应于反式-[Ru(16 - TMC或N₂O₂)(C≡CAr)₂]的配体内π - π*吸收能量。反式-[Ru(dmpe)₂{C≡C(C₆H₄C≡C)₂Ph}₂]的晶体结构表明分子的两条边相距41.7 Å。通过修饰L₄和Ar可以系统地调节这些配合物的电化学和光谱性质，使反式-[RuL₄(C≡CAr)₂]氧化的E(1/2)值跨度超过870 mV，反式-[RuL₄(C≡CAr)₂]的λ(max)值范围为19230至31750 cm⁻¹。总体实验结果表明反式-[RuL₄(C≡CAr)₂]中的π - 反馈键相互作用较弱，并且这些分子中的[RuL₄]部分在直线型刚性π共轭棒中可被视为起“掺杂剂”的作用。
