Zhao Shengliang, Arachchige Shamindri M, Slebodnick Carla, Brewer Karen J
Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0212, USA.
Inorg Chem. 2008 Jul 21;47(14):6144-52. doi: 10.1021/ic7023296. Epub 2008 Jun 24.
The mixed-metal supramolecular complexes (tpy)Ru(tppz)PtCl3 and ClPt(tppz)Ru(tppz)PtCl4 (tpy = 2,2':6',2''-terpyridine and tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) were synthesized and characterized. These complexes contain ruthenium bridged by tppz to platinum centers to form stereochemically defined linear assemblies. X-ray crystallographic determinations of the two complexes confirm the identity of the metal complexes and reveal intermolecular interactions of the Pt sites in the solid state for (tpy)Ru(tppz)PtCl3 with a Pt...Pt distance of 3.3218(5) A. The (1)H NMR spectra show the expected splitting patterns characteristic of stereochemically defined mixed-metal systems and are assigned with the use of (1)H-(1)H COSY and NOESY. Electronic absorption spectroscopy displays intense ligand-based pi --> pi* transitions in the UV and MLCT transitions in the visible. Electrochemically (tpy)Ru(tppz)PtCl3 and ClPt(tppz)Ru(tppz)PtCl4 display reversible Ru (II/III) couples at 1.63 and 1.83 V versus Ag/AgCl, respectively. The complexes display very low potential tppz (0/-) and tppz(-/2-) couples, relative to their monometallic synthons, (tpy)Ru(tppz)2 and Ru(tppz)22, consistent with the bridging coordination of the tppz ligand. The Ru(dpi) --> tppz(pi*) MLCT transitions are also red-shifted relative to the monometallic synthons occurring in the visible centered at 530 and 538 nm in CH3CN for (tpy)Ru(tppz)PtCl3 and ClPt(tppz)Ru(tppz)PtCl4, respectively. The complex (tpy)Ru(tppz)PtCl3 displays a barely detectable emission from the Ru(dpi) --> tppz(pi*) (3)MLCT in CH 3CN solution at RT. In contrast, ClPt(tppz)Ru(tppz)PtCl4 displays an intense emission from the Ru(dpi) --> tppz(pi*) (3)MLCT state at RT with lambda max(em) = 754 nm and tau = 80 ns.
合成并表征了混合金属超分子配合物(tpy)Ru(tppz)PtCl3和ClPt(tppz)Ru(tppz)PtCl4（tpy = 2,2':6',2''-三联吡啶，tppz = 2,3,5,6-四(2-吡啶基)吡嗪）。这些配合物包含通过tppz桥连到铂中心的钌，形成立体化学定义的线性组装体。两种配合物的X射线晶体学测定证实了金属配合物的结构，并揭示了(tpy)Ru(tppz)PtCl3固态中Pt位点的分子间相互作用，Pt...Pt距离为3.3218(5) Å。(1)H NMR光谱显示了立体化学定义的混合金属体系特有的预期分裂模式，并通过(1)H-(1)H COSY和NOESY进行了归属。电子吸收光谱在紫外区域显示出强烈的基于配体的π→π跃迁，在可见光区域显示出MLCT跃迁。电化学方面，(tpy)Ru(tppz)PtCl3和ClPt(tppz)Ru(tppz)PtCl4相对于Ag/AgCl分别在1.63和1.83 V处显示出可逆的Ru (II/III) 氧化还原对。相对于它们的单金属合成子(tpy)Ru(tppz)2和Ru(tppz)22，这些配合物显示出非常低电位的tppz (0/-) 和tppz(-/2-) 氧化还原对，这与tppz配体的桥连配位一致。(tpy)Ru(tppz)PtCl3和ClPt(tppz)Ru(tppz)PtCl4的Ru(dpi)→tppz(π) MLCT跃迁相对于在乙腈中分别以530和538 nm为中心的可见光区域中发生的单金属合成子也发生了红移。配合物(tpy)Ru(tppz)PtCl3在室温下的乙腈溶液中从Ru(dpi)→tppz(π*) (3)MLCT显示出几乎检测不到的发射。相比之下，ClPt(tppz)Ru(tppz)PtCl4在室温下从Ru(dpi)→tppz(π*) (3)MLCT态显示出强烈发射，λmax(em) = 754 nm，τ = 80 ns。
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