Static magnetic susceptibility and ESR studies of 1:1 and 1:2 charge-transfer complexes of naphthaceno-[5,6-cd:11,12-c′d′]bis[1,2]dithiole and 2,2′-(2,5-cyclohexadiene-1,4-diylidene)bis(propanedinitrile) [(TTT)(TCNQ) and (TTT)(TCNQ)2] in the temperature region of 2–310 K are described. (TTT)(TCNQ)2 exhibits a temperature dependent spin susceptibility, while the spin susceptibility of (TTT)(TCNQ) is almost independent of temperature. Spin susceptibilities of the TTT and TCNQ chains, which are evaluated with a g-value decomposition technique, are interpreted in terms of a one-dimensional Hubbard model. In both complexes, the on-site Coulomb repulsion is comparable with or larger than the band width on the TCNQ chains and is smaller on the TTT chains. Two magnetic phase transitions are observed in (TTT)(TCNQ)2. The transition is driven in each chain independently by the Peierls instability. The amount of charge transfer in (TTT)(TCNQ) is determined to be 0.73±0.05 from an X-ray photoelectron spectroscopic study.
关于
萘并[5,6-cd:11,12-c′d′]双[1,2]二
硫杂
环戊烯与2,2′-(2,5-环
己二烯-1,4-二亚甲基)双(
丙二腈)[(
TTT)(TCNQ)和(
TTT)(TCNQ)2]的1:1和1:2电荷转移复合物在2-310 K温度区域的静磁化率和ESR研究结果如下:(
TTT)(TCNQ)2表现出依赖于温度的自旋磁化率,而(
TTT)(TCNQ)的自旋磁化率几乎与温度无关。利用g值分解技术评估的
TTT和TCNQ链的自旋磁化率,可以用一维哈伯德模型来解释。在这两种复合物中,TCNQ链上的在位库仑排斥与带宽相当或更大,而在
TTT链上则较小。在(
TTT)(TCNQ)2中观察到两次磁相变。这种转变是由Peierls不稳定性在每条链上独立驱动的。从X射线光电子光谱研究中确定(
TTT)(TCNQ)中的电荷转移量为0.73±0.05。