Mévellec Franck, Lepareur Nicolas, Roucoux Alain, Noiret Nicolas, Patin Henri, Bandoli Giuliano, Porchia Marina, Tisato Francesco
Laboratoire de Chimie des Biomolécules et des Systèmes Organisés, CNRS UMR 6052, Ecole Nationale Supérieure de Chimie de Rennes (ENSCR), 35700 Rennes, France.
Inorg Chem. 2002 Mar 25;41(6):1591-7. doi: 10.1021/ic0110979.
Neutral and asymmetrical hydrazido(3-)rhenium(V) heterocomplexes of the type [Re(eta(2)-L(4))(L(n))(PPh(3))] (eta(2)-L(4) = NNC(SCH(3))S; H(2)L(1) = S-methyl beta-N-((2-hydroxyphenyl)ethylidene)dithiocarbazate, 1, H(2)L(2) = S-methyl beta-N-((2-hydroxyphenyl)methylidene)dithiocarbazate, 2) are prepared via ligand-exchange reactions in ethanolic solutions starting from Re(V)(O)Cl(4) in the presence of PPh(3) or from [Re(V)(O)Cl(3)(PPh(3))(2)]. The distorted octahedral coordination sphere of these compounds is saturated by a chelated hydrazido group, a facially ligated ONS Schiff base, and PPh(3). Reduction-substitution reactions starting from [NH(4)][Re(VII)O(4)] in acidic ethanolic mixtures containing PPh(3) and H(2)L(n) (or its dithiocarbazic acid precursor H(3)L(4)) produce another example of chelated hydrazido(3-) rhenium(V) derivative, namely [Re(eta(2)-L(4))Cl(2)(PPh(3))(2)], 3. On the contrary, the N-methyl-substituted dithiocarbazic acid H(2)L(3) reacts with perrhenate to give the known nitrido complex [Re(N)Cl(2)(PPh(3))(2)]. Rhenium(V) complexes incorporating the robust eta(2)-hydrazido moiety represent key intermediates helpful for the comprehension of the reaction pathway which generates nitridorhenium(V) species starting from oxo precursors. An essential requirement for the stabilization of such chelated hydrazido-Re(V) units is the triple deprotonation at the hydrazine nitrogens, thereby providing efficient pi-electron circulation in the resulting five-membered ring. The thermal stability of these units is affected by the nature of the anchoring donor, thione sulfur ensuring stronger chelation than nitrogen and oxygen. The eta(2)-hydrazido complexes are characterized by conventional physicochemical techniques, including the X-ray crystal structure determination of 1 and 3.
[Re(η²-L⁴)(Lⁿ)(PPh₃)]类型的中性和不对称酰肼基（3-）铼（V）杂配合物（η²-L⁴ = NNC(SCH₃)S；H₂L¹ = S-甲基-β-N-((2-羟基苯基)亚乙基)二硫代氨基甲酸盐，1，H₂L² = S-甲基-β-N-((2-羟基苯基)亚甲基)二硫代氨基甲酸盐，2）是通过在乙醇溶液中，在三苯基膦存在下，由[Re(V)(O)Cl₄]⁻或由[Re(V)(O)Cl₃(PPh₃)₂]开始的配体交换反应制备的。这些化合物扭曲的八面体配位球由一个螯合的酰肼基团、一个面式配位的ONS席夫碱和三苯基膦饱和。在含有三苯基膦和H₂Lⁿ（或其二硫代氨基甲酸前体H₃L⁴）的酸性乙醇混合物中，由[NH₄][Re(VII)O₄]开始的还原-取代反应产生了另一个螯合酰肼基（3-）铼（V）衍生物的例子，即[Re(η²-L⁴)Cl₂(PPh₃)₂]，3。相反，N-甲基取代的二硫代氨基甲酸H₂L³与高铼酸盐反应生成已知的氮化物配合物[Re(N)Cl₂(PPh₃)₂]。包含稳定的η²-酰肼部分的铼（V）配合物是理解从氧代前体生成氮化物铼（V）物种的反应途径的关键中间体。稳定这种螯合酰肼-铼（V）单元的一个基本要求是肼氮上的三重去质子化，从而在所得的五元环中提供有效的π电子循环。这些单元的热稳定性受锚定供体性质的影响，硫酮硫比氮和氧确保更强的螯合作用。通过传统的物理化学技术对η²-酰肼配合物进行了表征，包括对1和3的X射线晶体结构测定。
