Abstract

2,5-Dihydroxy-3,6-di-tert-butyl-p-benzoquinone (Q^tBuDiol) reacts with Ph₃SbBr₂ in toluene in the presence of triethylamine to yield the ionic complex [Et₃NH]⁺[(Dione^tBuDiolate)SbPh₃Br]^– (I). The same reaction in methanol leads to complete displacement of bromide ions from the antimony coordination sphere and gives triphenylantimony(V) 1,2-diolate (Dione^tBuDiolate)SbPh₃ · MeOH (II · MeOH). The molecular structure of the complexes was determined by X-ray diffraction (CIF files CCDC no. 1960681 (I · toluene) and 1960682 (II · 2MeOH)). Both complexes are characterized by quinoid bond distribution in the six-membered carbon rings and by C=O double bonds in the Ph₃SbO₂C₆(t-Bu)₂O₂ moieties. Formally, the complexes can be considered as 3,6-di-tert-butyl-o-benzoquinone derivatives with the organometallic Ph₃SbO₂ group in positions 4 and 5 of the quinone ring. The electrochemical reduction of II · MeOH in dichloromethane occurs at E_1/2 = –1.52 V, which is significantly shifted to the cathodic region relative to the data for 3,6-di-tert-butyl-o-benzoquinone (E_1/2 = –0.51 V). This redox potential shift indicates a significant decrease in the electron-withdrawing properties of the o-quinoid moiety, which is caused by the effect of the electron-donating catecholate metallacycle.

中文翻译：

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基于3,6-二叔丁基-2,5-二羟基-1,4-苯醌的三苯基锑（V）邻苯二酚

摘要

2,5-二羟基-3,6-二-叔丁基- p苯醌（Q^吨卜二醇）反应的Ph ₃ SBBR ₂在甲苯中在三乙胺存在下，得到离子络合物[等₃ NH] ⁺ [ （Dione ^{t Bu} Diolate）SbPh ₃ Br] ^–（I）。在甲醇中进行相同的反应会导致溴离子从锑配位球中完全移出，并生成三苯基锑（V）1,2-二醇盐（Dione ^{t Bu} Diolate）SbPh ₃ ·MeOH（II·MeOH）。通过X射线衍射测定复合物的分子结构（CIF文件，CCDC号1960681（I ·甲苯）和1960682（II ·2MeOH））。两种络合物的特征均在于六元碳环中的醌键分布和Ph ₃ SbO ₂ C ₆（t- Bu）₂ O ₂部分中的C = O双键。形式上，该络合物可以被认为是在醌环的第4位和第5位具有有机金属Ph ₃ SbO ₂基团的3,6-二叔丁基-邻苯并醌衍生物。II的电化学还原·二氯甲烷中的MeOH发生在E _1/2 = –1.52 V，相对于3,6-二叔丁基-邻-苯并醌的数据（E _1/2 = –0.51 V），它显着转移到阴极区域）。该氧化还原电势位移表明邻-喹啉部分的吸电子性质显着下降，这是由于给电子儿茶酚金属环的作用引起的。