A series of 1′,1′′′-disubstituted biferrocenes was synthesized to study the influence of electron-withdrawing and electron-donating groups on the electronic interaction within the biferrocenyl unit. Therefore, biferrocenes of type R-bfc-R (bfc = 1:1″-biferrocen-1′,1′′′-diyl; R = 1,3-dioxan-2-yl (5a), H (5b), I (5c), 3,5-(CF₃)₂-C₆H₃ (5d), CHO (5e), CN (5f)) were prepared using different synthetic methodologies. Biferrocenes 5d,f have been structurally characterized by single-crystal X-ray diffraction analysis. Compound 5d shows a trans-configuration of the biferrocene moiety forming a two dimensional network based on intermolecular F···F interactions being parallel to (0–11) in the solid state. Electrochemical measurements display two separated reversible redox processes for the biferrocene unit. With an increase of the electron-withdrawing character of the substituents R, a shift of the first redox event to higher potentials is observed. For biferrocenes 5a–f the redox separations of the two individual redox processes range between 505 and 620 mV. Mixed-valent compounds [5a–5f]⁺ exhibit IVCT absorptions of moderate strength allowing to classify them as class II systems according to Robin and Day. The strongest interaction is found for biferrocene 5d with an IVCT intensity of 1540 L·mol^–1·cm^–1 and a full-width-at-half-height of 2900 cm^–1. The solvatochromism of biferrocene 5a,e,f was studied using the Kamlet-Taft LSE relationship showing similar solvatochromic properties for those compounds. An increase of the dipolarity/polarizability of the solvent results in a bathochromic shift of the λ_max values and increased hydrogen bond donor capacities result in a hypsochromic shift of λ_max

合成了一系列的1'，1'''-二取代双二茂铁，以研究吸电子和供电子基团对双二茂铁单元内电子相互作用的影响。因此，R-bfc-R（bfc = 1：1''-biferrocen-1'，1'''-diyl; R = 1,3-dioxan-2-yl（5a），H（5b），使用不同的合成方法制备了I（5c），3,5-（CF ₃）₂ -C ₆ H ₃（5d），CHO（5e），CN（5f））。通过单晶X射线衍射分析已对双茂铁5d，f进行了结构表征。化合物5d显示基于分子间F···F相互作用在固态下平行于（0-11）的二茂铁部分的反式构型，形成一个二维网络。电化学测量结果显示，二茂铁单元有两个分离的可逆氧化还原过程。随着取代基R的吸电子特性的增加，观察到第一氧化还原事件向更高电势的转变。对于双二茂铁5a – f，两个单独的氧化还原过程的氧化还原间隔介于505和620 mV之间。混合价化合物[ 5a – 5f ] ⁺表现出中等强度的IVCT吸收，可以根据Robin和Day将其分类为II类系统。发现二茂铁5d的相互作用最强，其IVCT强度为1540 L·mol ^–1 ·cm ^–1，半高全宽为2900 cm ^–1。使用Kamlet -Taft LSE关系研究了二茂铁5a，e，f的溶剂变色，显示出这些化合物的相似的溶剂变色特性。溶剂的偶极/极化率增加会导致_λmax值发生红移，而氢键供体容量的增加会导致_λmax发生蓝移。