Department of Chemistry, The University of Tennessee at Chattanooga, Chattanooga, TN 37403, USA.
Dalton Trans. 2009 Oct 28(40):8605-15. doi: 10.1039/b909875e. Epub 2009 Aug 19.
We report the synthesis and full characterization for a series of thiacrown complexes of Pt(II) incorporating the fluxional trithiacrown ligand 1,4,7-trithiacyclononane ([9]aneS3) and several group 15 donors ligands. Reaction of [Pt([9]aneS3)Cl2] with a full stoichiometric equivalent of the group 15 donor (L = 2 x AsPh3, SbPh3 or 1,2-bis(diphenylarsenio) ethane (dpae) followed by metathesis with NH4PF6 yields Pt([9]aneS3)L2. We also report the analogous Pd(II) complex with dpae. Similar reactions of the starting Pt complex with one equivalent of XPh3 (X = As or Sb) result in complexes of the formula Pt([9]aneS3)(XPh3)(Cl). All six new complexes have been fully characterized by multinuclear NMR, IR, and UV-Vis spectroscopies in addition to elemental analysis and single crystal structural determinations. The X-ray structures of each complex indicate an axial M-S interaction formed by the endodentate conformation of the [9]aneS3 ligand. The axial M-S distance is highly dependent upon the ancillary donor set. The axial M-S distance shortens with the identity of the group 15 donor ligand according to the trend, Sb < As < P, due to their increasingly poorer donor qualities. The two bis pnictogen complexes, Pt([9]aneS3)(AsPh3)22 and Pt([9]aneS3)(SbPh3)22 form unusual five-coordinate distorted trigonal bipyramids in contrast to the pseudo-five coordinate, elongated square pyramidal structures typically observed in Pt(II) complexes of [9]aneS3. The distortion arises from intramolecular pi-pi interactions between the phenyl rings on the two different triphenyl ligands. Chemical shifts in the 195Pt NMR also show similar periodic relationships which trend progressively upfield as the donor atom becomes larger. As expected, the coordinated [9]aneS3 ligand shows fluxional behavior in its NMR spectra, resulting in a single 13C NMR resonance, despite the asymmetric coordination environment found in both chloro complexes. The line width for the carbon NMR resonance as well as for the 195Pt NMR peak is highly sensitive to the nature of the group 15 donor, with poorer donors such as SbPh3 showing significant line broadening. Measurements from the electronic spectra support that the ligand field strength of the pnictogen donor decreases with its increasing size.
我们报告了一系列包含可变形三硫杂冠配体 1,4,7-三硫杂环壬烷([9]aneS3)和几种第 15 族给体配体的 Pt(II)硫杂冠配合物的合成和全谱表征。[Pt([9]aneS3)Cl2]与第 15 族给体（L = 2 x AsPh3、SbPh3 或 1,2-双（二苯基砷基）乙烷（dpae））的化学计量全当量反应，然后与 NH4PF6 进行复分解反应，得到Pt([9]aneS3)L2。我们还报告了类似的 Pd(II)与 dpae 的配合物。起始 Pt 配合物与等当量的 XPh3（X = As 或 Sb）的类似反应导致Pt([9]aneS3)(XPh3)(Cl)的配合物。除了元素分析和单晶结构测定外，所有六个新配合物均通过多核 NMR、IR 和 UV-Vis 光谱学进行了全面表征。每个配合物的 X 射线结构表明轴向 M-S 相互作用是由[9]aneS3 配体的内齿构象形成的。轴向 M-S 距离高度依赖于辅助给体集。轴向 M-S 距离随第 15 族给体配体的身份而缩短，根据趋势为 Sb < As < P，这是由于它们的给体性质越来越差。两个双磷属元素配合物Pt([9]aneS3)(AsPh3)22 和Pt([9]aneS3)(SbPh3)22 形成不寻常的五配位扭曲三角双锥结构，与通常在[9]aneS3 的 Pt(II)配合物中观察到的拟五配位伸长的四方锥结构形成对比。这种扭曲是由于两个不同的三苯基配体上的苯基环之间的分子内π-π相互作用引起的。195Pt NMR 中的化学位移也显示出类似的周期性关系，随着给体原子变大，化学位移逐渐向场下移。正如预期的那样，尽管在两个氯配合物中发现了不对称配位环境，但配位的[9]aneS3 配体在其 NMR 光谱中表现出易变行为，导致仅出现一个 13C NMR 共振。碳 NMR 共振和 195Pt NMR 峰的线宽对磷属元素给体的性质非常敏感，较差的给体如 SbPh3 显示出明显的线宽变宽。来自电子光谱的测量支持磷属元素给体的配体场强度随其尺寸的增加而降低。
