Studies on Preparation and Characterization of Phthalocyanines with the Trithiole Rings

1，4，8，11，15，18，22，25-Octalkyl-2，3，9，10，16，17，23，24-tetrakis(o-xylylene-dithio)phthalocyanines(1a，b)[烷基=丁基和辛基]是用锂在正戊醇中与3，6-dialkyl-4，5-(o-xylylenedithio)-phthalonitriles反应，以中等产率合成的。用Li/THF/NH_3还原脱除1a，b上的4个邻二甲苯基团，生成的八硫杂阴离子与单质硫反应生成含四个三硫醇环的新的三硫基酞菁(3a，b)。用~1H核磁共振和MALDI-TOF MS对其结构进行了表征，在UV-Vis光谱中观察到1a，b的Q带在λ&lt；max&gt；=770 nm附近有吸收，而3a，b的Q带在相对蓝移的区域附近有吸收。当在浓硫酸中测量3b的UV-Vis光谱时，Q带的λ&lt；max&gt；值为887 nm(logε=4.5)，这表明3b上产生的正电荷强烈地影响了酞菁骨架的π共轭。用SbCl5处理3b，观察到ESR谱为一个展宽信号。

1,4,8,11,15,18,22,25-Octalkyl-2,3,9,10,16,17,23,24-tetrakis(o-xylylene-dithio)phthalocyanines (1a,b) [alkyl=butyl and octyl] were prepared in moderate yields on treatment of 3,6-dialkyl-4,5-(o-xylylenedithio)-phthalonitriles with lithium in n-pentanol. Reductive removal of four o-xylylene groups from 1a,b was performed with Li/THF/NH_3,and octathiolate anions generated were then reacted with elemental sulfur to give new phthalocyanines (3a,b) with four trithiole rings, respectively, after partial desulfurization and ring contraction reactions of corresponding phthalocyanines (2a,b). The structures of phthalocyanines were determined with ^1H NMR and MALDI-TOF MS. The absorption of the Q-band of 1a,b was observed at around λ_<max>=770 nm in the UV-vis spectra, while that of 3a,b was found at around a relatively blueshifted region. When the UV-vis spectrum for 3b was measured in concentrated sulfuric acid, the λ_<max> value of the Q-band was 887 nm (log ε=4.5), which suggests that the positive charge generated on 3b strongly affects the π-conjugation of the phthalocyanine skeleton. The ESR spectrum was observed as one broadening signal on treatment of 3b with SbCl_5.