1,1-双二茂铁基烷的合成与表征

Synthesis and Characterization of Some Bis-ferrocenylalkanes

采用浓硫酸甲醇为催化剂,以甲苯为溶剂进行二茂铁与醛的缩合反应,比较了二茂铁与缩醛和二茂铁与醛、甲醇及微量浓硫酸混合物缩合反应的结果,发现二者的结果相近,而后者省去了缩醛的合成步骤;经真空升华除去未反应的二茂铁,柱层析分离得到了8种1,1双二茂铁基烷。通过元素分析、红外光谱、核磁共振氢谱测试技术对这些化合物的结构进行了表征;该类化合物红外光谱的特征为3080～3096cm-1的νC—H(Fc—H),1HNMR的特征为桥碳原子上的质子由于受2个二茂基的去屏蔽作用而位于较低场,化学位移(δ)为3.0左右;测定了1,1双二茂铁基己烷的质谱,发现分子离子峰M+(m/z=454.1)和碎片离子(Fc)2CH+(m/z=383.0)为基峰;1,1双二茂铁基己烷的电化学性质研究表明,有2对氧化还原峰,各自对应Fe(Ⅱ)Fe(Ⅱ)Fe(Ⅱ)Fe(Ⅲ)和Fe(Ⅱ)Fe(Ⅲ)Fe(Ⅲ)Fe(Ⅲ),2步电化学反应均具有化学可逆性。

Ferrocene was condensed with aldehyde in toluene with the mixture of methanol and concentrated sulfuric acid as the catalyst. The condensation reactions of ferrocene with aldehyde acetal and with the mixture of aldehyde, methanol and micro-amount of concentrated sulfuric acid were compared. It was found that the results of the two methods were similar. However, the process of synthesizing aldehyde acetal was not (necessary) in the later method. After the unreacted ferrocene was removed via vacuum sublimation, eight 1,1-bisferrocenylalkanes were obtained with chromatography. The structures of these compounds were characterized by means of elemental analysis, IR and ^(1)H NMR spectra. The characteristic bands of these compounds are in the range of 3 080^(3 096 cm^(-1)) for ν_(C—H)(Fc—H) in IR spectra. In the ~1H NMR spectra, the peaks of the protons (attached) to the bridge carbon atoms are shifted to lower field and their chemical shifts(δ) are about 3.0. The mass spectra and electrochemical properties of 1,1-bisferrocenylhexane were also determined. Both molecular ion peak at m/z=454.1 and fragment ion peak of (Fc)_(2)CH^(+) at m/z=383.0 are base peaks. The electrochemical (properties) of 1,1-bisferrocenylhexane show that there are two pairs of oxidation and reduction peaks, corresponding to Fe(Ⅱ)Fe(Ⅱ)  Fe(Ⅱ)Fe(Ⅲ) and Fe(Ⅱ)Fe(Ⅲ)  Fe(Ⅲ)Fe(Ⅲ) respectively. The two electrochemical reactions are reversible.