Department of Chemistry, University of Patras, GR-265 04 Patras, Greece.
Inorg Chem. 2012 Jul 16;51(14):7699-710. doi: 10.1021/ic300739x. Epub 2012 Jun 28.
Employment of the monoanion of 2,6-diacetylpyridine dioxime (dapdoH(2)) as a tridentate chelate in palladium(II) and platinum(II) chemistry is reported. The syntheses, crystal structures, spectroscopic and physicochemical characterization, and biological evaluation are described of [PdCl(dapdoH)] (1) and [PtCl(dapdoH)] (2). Reaction of PdCl(2) with 2 equivs of dapdoH(2) in MeOH under reflux gave 1, whereas the same reaction with PtCl(2) in place of PdCl(2) gave 2 in comparable yields (70-80%). The divalent metal center in both compounds is coordinated by a terminal chloro group and a N,N',N"-tridentate chelating (η(3)) dapdoH(-) ligand. Thus, each metal ion is four coordinate with a distorted square planar geometry. Characterization of both complexes with (1)H and (13)C NMR and UV-vis and electrospray ionization mass spectroscopies confirmed their integrity in DMSO solutions. Interaction of the complexes with human and bovine serum albumin has been studied with fluorescence spectroscopy, revealing their affinity for these proteins with relatively high values of binding constants. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that they can bind to CT DNA, and the corresponding DNA binding constants have been evaluated. Cyclic voltammograms of the complexes in the presence of CT DNA solution have shown that the interaction of the complexes with CT DNA is mainly through intercalation, which has been also shown by DNA solution viscosity measurements. Competitive studies with ethidium bromide (EB) have revealed the ability of the complexes to displace the DNA-bound EB, suggesting competition with EB. The combined work demonstrates the ability of pyridyl-dioxime chelates not only to lead to polynuclear 3d-metal complexes with impressive structural motifs and interesting magnetic properties but also to yield new, mononuclear 4d- and 5d-metal complexes with biological implications.
报道了 2,6-二乙酰基吡啶二肟（dapdoH（2））的单阴离子作为钯（II）和铂（II）化学中的三齿螯合剂的应用。描述了[PdCl（dapdoH）]（1）和[PtCl（dapdoH）]（2）的合成、晶体结构、光谱和物理化学特性以及生物学评价。在 MeOH 回流下，PdCl2 与 2 当量的 dapdoH（2）反应得到 1，而用 PtCl2 代替 PdCl2 进行相同反应得到 2，产率相当（70-80%）。两种化合物中的二价金属中心均由一个末端氯基团和一个 N，N'，N"-三齿螯合（η（3））dapdoH（-）配体配位。因此，每个金属离子都是四配位的，具有扭曲的平面四方几何形状。用（1）H 和（13）C NMR 以及紫外可见和电喷雾电离质谱对两种配合物进行了表征，证实了它们在 DMSO 溶液中的完整性。用荧光光谱研究了配合物与人血清白蛋白和牛血清白蛋白的相互作用，发现它们与这些蛋白质具有相对较高的结合常数的亲和力。配合物与小牛胸腺 DNA（CT DNA）的相互作用的 UV 研究表明，它们可以与 CT DNA 结合，并评估了相应的 DNA 结合常数。在 CT DNA 溶液存在下的配合物的循环伏安图表明，配合物与 CT DNA 的相互作用主要是通过嵌入，这也通过 DNA 溶液粘度测量得到证实。与溴化乙锭（EB）的竞争研究表明，配合物具有取代 DNA 结合的 EB 的能力，表明与 EB 竞争。综合研究表明，吡啶二肟螯合物不仅能够导致具有令人印象深刻的结构模式和有趣磁性质的多核 3d-金属配合物，而且还能够产生具有生物学意义的单核 4d-和 5d-金属配合物。
