Kowalski Konrad, Karpowicz Rafał, Mlostoń Grzegorz, Miesel Dominique, Hildebrandt Alexander, Lang Heinrich, Czerwieniec Rafał, Therrien Bruno
Faculty of Chemistry, Department of Organic Chemistry, University of Łódź, Tamka 12, PL-91403 Łódź, Poland.
Dalton Trans. 2015 Apr 7;44(13):6268-76. doi: 10.1039/c5dt00246j.
Three novel diferrocenyl complexes were prepared and characterised. 2,2-Diferrocenyl-4,5-dimethyl-3,6-dihydro-2H-thiopyran (1, sulphide) was accessible by the hetero-Diels-Alder reaction of diferrocenyl thioketone with 2,3-dimethyl-1,3-butadiene. Stepwise oxidation of 1 gave the respective oxides 2,2-diferrocenyl-4,5-dimethyl-3,6-dihydro-2H-thiopyran-1-oxide (2, sulfoxide) and 2,2-diferrocenyl-4,5-dimethyl-3,6-dihydro-2H-thiopyran-1,1-dioxide (3, sulfone), respectively. The molecular structures of 1 and 3 in the solid state were determined by single crystal X-ray crystallography. The oxidation of sulphide 1 to sulfone 3, plays only a minor role on the overall structure of the two compounds. Electrochemical (cyclic voltammetry (= CV), square wave voltammetry (= SWV)) and spectroelectrochemical (in situ UV-Vis/NIR spectroscopy) studies were carried out. The CV and SWV measurements showed that an increase of the sulphur atom oxidation from -2 in 1 to +2 in 3 causes an anodic shift of the ferrocenyl-based oxidation potentials of about 100 mV. The electrochemical oxidation of 1-3 generates mixed-valent cations 1(+)-3(+). These monooxidised species display low-energy electronic absorption bands between 1000 and 3000 nm assigned to IVCT (= Inter-Valence Charge Transfer) electronic transitions. Accordingly, the mixed-valent cations 1(+)-3(+) are classified as weakly coupled class II systems according to Robin and Day.
制备并表征了三种新型二茂铁基配合物。2,2 - 二茂铁基 - 4,5 - 二甲基 - 3,6 - 二氢 - 2H - 硫代吡喃（1，硫化物）可通过二茂铁基硫酮与2,3 - 二甲基 - 1,3 - 丁二烯的杂Diels - Alder反应制得。1的逐步氧化分别得到相应的氧化物2,2 - 二茂铁基 - 4,5 - 二甲基 - 3,6 - 二氢 - 2H - 硫代吡喃 - 1 - 氧化物（2，亚砜）和2,2 - 二茂铁基 - 4,5 - 二甲基 - 3,6 - 二氢 - 2H - 硫代吡喃 - 1,1 - 二氧化物（3，砜）。通过单晶X射线晶体学确定了固态下1和3的分子结构。硫化物1氧化为砜3对这两种化合物的整体结构影响较小。进行了电化学（循环伏安法（= CV）、方波伏安法（= SWV））和光谱电化学（原位紫外 - 可见/近红外光谱）研究。CV和SWV测量表明，硫原子氧化态从1中的 - 2增加到3中的 +2会导致基于二茂铁的氧化电位发生约100 mV的阳极偏移。1 - 3的电化学氧化产生混合价阳离子1(+) - 3(+)。这些单氧化物种在1000至3000 nm之间显示出低能量电子吸收带，归因于IVCT（= 价间电荷转移）电子跃迁。因此，根据Robin和Day的分类，混合价阳离子1(+) - 3(+)被归类为弱耦合的II类体系。
