Bolzati Cristina, Cavazza-Ceccato Mario, Agostini Stefania, Tisato Francesco, Bandoli Giuliano
ICIS-CNR, Corso Stati Uniti, 4, 35127 Padova, Italy.
Inorg Chem. 2008 Dec 15;47(24):11972-83. doi: 10.1021/ic801436d.
The reactivity of bulky alkylphosphino-thiol ligands (PSH) toward nitride-M(V, VI) (M = Tc/Re) precursors was investigated. Neutral five-coordinate monosubstituted complexes of the type [M(N)(PS)Cl(PPh(3))] (Tc1-4, Re1-2) were prepared in moderate to high yields. It was found that these [M(N)(PS)Cl(PPh(3))] species underwent ligand-exchange reactions under mild conditions when reacted with bidentate mononegative ligands having soft donor atoms such as dithiocarbamates (NaL(n)) to afford stable dissymmetrical mixed-substituted complexes of the type [M(N)(PS)(L(n))] (Tc5,8-10, Re5-9) containing two different bidentate chelating ligands bound to the M[triple bond]N moiety. In these reactions, the dithiocarbamate replaced the two labile monodentate ligands (Cl and PPh(3)) leaving the M(N)(PS) building block intact. In the above reactions, technetium and rhenium were found to behave in a similar way. Instead, under more drastic conditions, reactions of PSH with [M(N)Cl(2)(PPh(3))(2)] gave a mixture of monosubstituted [M(N)(PS)Cl(PPh(3))] and bis-substituted species [M(N)(PS)(2)] (Tc11-14) in the case of technetium, whereas only monosubstituted [M(N)(PS)Cl(PPh(3))] complexes were recovered for rhenium. All isolated products were characterized by elemental analysis, IR and multinuclear ((1)H, (13)C, and (31)P) NMR spectroscopies, ESI MS spectrometry, and X-ray crystal structure determination of the representative monosubstituted [Tc(N)(PStbu)Cl(PPh(3))] (Tc4) and mixed-substituted [Re(N)(PScy)(L(3))] (Re7) and [Re(N)(PSiso)(L(4))] (Re9) complexes. The latter rhenium complexes represent the first example of a square-pyramidal nitrido Re species with the basal plane defined by a PS(3) donor set. Monosubstituted [M(N)(PS)Cl(PPh(3))] species bearing the substitution-inert M(N)(PS) moieties act as suitable building blocks proposed for the construction of new classes of dissymmetrical nitrido compounds with potential application in the development of essential and target specific (99m)Tc and (188)Re radiopharmaceuticals for imaging and therapy, respectively.
研究了大体积烷基膦硫醇配体（PSH）与氮化物-M(V, VI)（M = Tc/Re）前体的反应活性。制备了中等至高收率的[M(N)(PS)Cl(PPh₃)]型中性五配位单取代配合物（Tc1-4，Re1-2）。发现这些[M(N)(PS)Cl(PPh₃)]物种在温和条件下与具有软供体原子的双齿单负配体（如二硫代氨基甲酸盐（NaLₙ））反应时会发生配体交换反应，从而得到稳定的不对称混合取代配合物[M(N)(PS)(Lₙ)]（Tc5,8-10，Re5-9），其中包含两个与[M≡N]²⁺部分结合的不同双齿螯合配体。在这些反应中，二硫代氨基甲酸盐取代了两个不稳定的单齿配体（Cl和PPh₃），而[M(N)(PS)]⁺结构单元保持完整。在上述反应中，发现锝和铼的行为相似。相反，在更剧烈的条件下，PSH与[M(N)Cl₂(PPh₃)₂]反应时，锝的情况下会得到单取代的[M(N)(PS)Cl(PPh₃)]和双取代物种[M(N)(PS)₂]（Tc11-14）的混合物，而铼只得到单取代的[M(N)(PS)Cl(PPh₃)]配合物。所有分离得到的产物都通过元素分析、红外光谱和多核（¹H、¹³C和³¹P）核磁共振光谱、电喷雾质谱以及代表性单取代[Tc(N)(PStbu)Cl(PPh₃)]（Tc4）、混合取代[Re(N)(PScy)(L₃)]（Re7）和[Re(N)(PSiso)(L₄)]（Re9）配合物的X射线晶体结构测定进行了表征。后两种铼配合物代表了第一个具有由PS₃供体组定义的基面的四方锥氮化物铼物种的例子。带有取代惰性[M(N)(PS)]⁺部分的单取代[M(N)(PS)Cl(PPh₃)]物种是构建新型不对称氮化物化合物的合适结构单元，这些化合物分别在开发用于成像和治疗的必需和靶向特异性⁹⁹ᵐTc和¹⁸⁸Re放射性药物方面具有潜在应用。
