作者:E. Stephen Davies、Georgina M. Aston、Roy L. Beddoes、David Collison、Andrew Dinsmore、Arefa Docrat、John A. Joule、Clare R. Wilson、C. David Garner
DOI:10.1039/a805688i
日期:——
The reaction of [WO2(CN)4]4â with a series of dimethylamino- or thione-protected asymmetric dithiolenes (ene-1,2-dithiolates) has been used to synthesise [WO(dithiolene)2]2â complexes (dithiolene = âSC(H)C(R)Sâ, R = phenyl, pyridin-2-yl, pyridin-3-yl, pyridin-4-yl or quinoxalin-2-yl), which have been characterised by elemental analysis, spectroscopy and electrochemistry. The prototypical compound [PPh4]2[WO(sdt)2]·EtOH [sdt = styrenedithiolate, âSC(H)C(Ph)Sâ], crystallises in space group P21/c with a = 13.242(4), b = 31.894(8), c = 14.589(5) Ã
, β = 113.80(2)°, and Z = 4. The WOS4 moiety is square-based pyramidal with the O atom at the apex [WO 1.724(7) Ã
, WâSav 2.37 Ã
, OâWâSav 108.7°] and contains a cis geometry of the phenyl groups, although 1H NMR studies indicate that both cis and trans isomers are present in the isolated solid. The physical properties of all of the [WO(dithiolene)2]2â complexes are consistent with a retention of the WIVOS4 centre and each system undergoes a reversible electrochemical one-electron oxidation to the corresponding WV system. The variation in the dithiolene 1H NMR resonances, ν(WO) and ν(CC) (dithiolene) IR stretching frequencies, and the E½ values for the WVâWIV couple can be rationalised by a consideration of the nature of the aryl substituent. These data are compared to those of the analogous MoIV complexes and to those of the catalytic centres of the tungstoenzymes and their oxomolybdoenzyme counterparts.
[WO2(CN)4]4-与一系列二甲氨基或硫酮保护的不对称二硫醇(烯-1,2-二硫醇)的反应已用于合成[WO(二硫醇)2]2-配合物(二硫烯=-SC(H)C(R)S-,R=苯基,吡啶-2-基,吡啶-3-基,吡啶-4-基或喹喔啉-2-基),其中通过元素分析、光谱学和电化学对其进行了表征。典型化合物 [PPh4]2[WO(sdt)2]·EtOH [sdt=二硫代苯乙烯, -SC(H)C(Ph)S-],在空间群 P21/c 中结晶,a = 13.242(4)、b=31.894(8)、c=14.589(5) ×、β=113.80(2)°和 Z=4。WOS4 部分是带有 O 原子的方形锥体位于顶点 [WO 1.724(7) �, W�Sav 2.37�, O�W�Sav 108.7°] 并包含苯基的顺式几何结构,尽管 1H NMR 研究表明顺式和反式异构体存在于分离的固体中。所有[WO(二硫烯)2]2-配合物的物理性质与WIVOS4中心的保留一致,并且每个系统都经历可逆的电化学单电子氧化至相应的WV系统。二硫醇 1H NMR 共振、δ(WO) 和 δ(CC)(二硫醇)IR 伸缩频率以及 WV-WIV 电对的 E 值的变化可以通过考虑芳基取代基的性质来合理化。将这些数据与类似的 MoIV 复合物的数据以及钨酶及其氧化钼酶对应物的催化中心的数据进行比较。