Bi- and trimetallic platinum(bipyridine)(dithiolene) complexes involving different organic linkers between the redox active platinum(dithiolene) moieties have been synthesized and studied by electrochemistry and spectroelectrochemistry. Cyclic voltammetry experiments carried out on these multinuclear complexes in dichloromethane using [NBu₄][PF₆] as the supporting salt show only one oxidation process involving the metallacycles. Nevertheless, spectro-electrochemical studies, carried out under the same conditions, show a different evolution of the spectra during oxidation depending on the position of the metallacycles on the phenyl ring. For instance, only the 1,3-disubtituted (Pt₂1,3-P) and 1,3,5-trisubstituted (Pt₃1,3,5-P) complexes show the growth of an absorption band in the NIR region upon oxidation while it was not observed for the other complexes. In contrast, electrochemical studies carried out using the poorly coordinating supporting electrolyte, [Na][B(C₆H₄(CF₃)₂)₄], indicate sequential oxidation of the redox centers with ΔE values varying according to the nature of the bridge and the distance between metal centers. For all the investigated multinuclear complexes, spectro-electrochemical experiments performed in the presence of [Na][B(C₆H₄(CF₃)₂)₄] show an absorption band in the NIR region consistent with appreciable electrostatic effects and charge delocalization in the mixed valent intermediates.

中文翻译：

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氧化多核 Pt（联吡啶）（二硫代烯）配合物中的静电与电子相互作用


通过电化学和光谱电化学合成了涉及氧化还原活性铂（二硫代）部分之间不同有机接头的双金属和三金属铂（联吡啶）（二硫代烯）配合物。使用 [NBu₄][PF₆] 作为支持盐对二氯甲烷中的这些多核配合物进行的循环伏安实验表明，只有一个涉及金属环的氧化过程。然而，在相同条件下进行的光谱电化学研究表明，根据苯基环上金属环的位置，氧化过程中光谱的演变不同。例如，只有 1,3-二取代 （Pt₂1,3-P） 和 1,3,5-三取代 （Pt₃1,3,5-P） 复合物在氧化后在 NIR 区域显示吸收带的增长，而其他复合物则没有观察到。相比之下，使用配位不良的支持电解质 [Na][B（C₆H₄（CF₃）₂）₄] 进行的电化学研究表明，氧化还原中心的顺序氧化，ΔE 值根据电桥的性质和金属中心之间的距离而变化。对于所有研究的多核配合物，在 [Na][B（C₆H₄（CF₃）₂）₄] 存在下进行的光谱电化学实验显示，NIR 区域中的吸收带与混合价中间体中明显的静电效应和电荷离域一致。