Design and development of photo-induced organic molecular metals

(1)设计了TTF与1，3-二巯基-2-亚基（DT-TTF）和C60（1）的杂化体系，并对其电子结构进行了研究。分子轨道计算表明，DT-TTF和C_<60>单元分别对HOMO和LUMO起主要作用. DT-TTF和C_2<60>基团分别具有正电荷和负电荷，表明分子内电荷转移。另一方面，HOMO-LUMO带隙1分别比DT TTF和C_的HOMO-LUMO带隙小3.02和1.07 eV<60>。(2)合成了1的几种衍生物。1的循环伏安图由两个对应于TTF的可逆氧化波和四个对应于C_部分的还原波组成<60>。由于C_2的吸电子作用，其氧化电位高于相应的DT TTF衍生物<60>。同样，由于给电子基团的给电子效应，还原电位比C_2的还原电位更负<60>。它们在压缩颗粒上的电导率为σ_<rt>= 10^<-8>S cm^<-1>。(3)合成了几种寡聚稠合延伸的TTF衍生物，其中插入了噻吩。三稠合衍生物的循环伏安图由两对双电子转移波和两对单电子转移波组成，而双稠合衍生物的循环伏安图由四对单电子转移波组成。上述结果表明，正电荷在整个分子上离域。在紫外维斯光谱中，这些寡聚融合的extended-TTF的最大吸收出现在485 nm附近，并没有观察到来自于extended-TTF单元的增加的较长波长区域的显著偏移。

(1) Hybrid system composed of TTF fused with 1,3-dithiol-2-ylidene (DT TTF) and C60 (1) has been designed, and its electronic structure has been investigated. The molecular orbital calculation of the unsubstituted-1 suggests that the DT TTF and C_<60> units mainly contribute to the HOMO and LUMO, respectively. The DT TTF and C_<60> moieties have positive and negative, respectively, indicating intramolecular charge-transfer. On the other hand, HOMO-LUMO gap of 1 is significantly smaller by 3.02 and 1.07 eV compared with those of DT TTF and C_<60>, respectively.(2) Several derivatives of 1 have been synthesized. Cyclic voltammogram of 1 consists of two reversible oxidation waves corresponding to the TTF and four reduction ones due to C_<60> moiety. The oxidation potentials are higher than those of the corresponding DT TTF derivative due to electron-withdrawing effect of C_<60>. In a similar manner, the reduction potentials are more negative than those of C_<60> because of electron-donating effect of the donor moiety. They showed electrical conductivity of σ_<rt> = 10^<-8>S cm^<-1> on compressed pellets.(3) Several derivatives of oligo-fused extended-TTF, in which thiophene is inserted, have been synthesized. Cyclic voltammogram of the tris-fused derivative consists of two pairs of two-electron transfer waves and two pairs of one-electron ones, while the bis-fused analog exhibits four pairs of one-electron transfer waves. The above results indicate that the positive charges delocalize on the whole molecule. In the UV vis spectra of these oligo-fused extended-TTFs, the absorption maxima appeared around 485 nm, and no significant shift to the longer wavelength region was observed derived from increase of extended-TTF units.