Discotic liquid crystals of transition metal complexes, 31: establishment of mesomorphism and thermochromism of bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel complexes
作者:Hiroko Horie、Akira Takagi、Hiroshi Hasebe、Takumi Ozawa、Kazuchika Ohta
DOI:10.1039/b007135h
日期:——
Two series of bis[1,2-bis(4-n-alkylphenyl)ethane-1,2-dithiolene]nickel,
Cn–Ni (n = 1–12),
and bis[1,2-bis(4-n-alkoxyphenyl)ethane-1,2-dithiolene]nickel,
CnO–Ni(n = 1–12,
14, 16, 18), have been synthesized. Their mesomorphism, thermochromism,
supramolecular structures and π-acceptor property have been investigated
by using different scanning calorimetry, polarizing microscopy, temperature-dependent
X-ray diffraction technique, electronic spectroscopy and cyclic voltammetry.
From the X-ray diffraction and electronic spectral results, it was established
that the CnO–Ni complexes for n≤10 exhibit two
differently colored discotic lamellar (DL) mesophases
whereas none of the Cn–Ni complexes has a mesophase,
and that the thermochromism (brown → green) is
attributable to a slow transformation from the Ni–Ni bonded dimers to
the Ni–S bonded dimers.
两系列双[1,2-双(4-正烷基苯基)乙烷-1,2-二硫醇]镍,Cn–Ni(n=1–12),和双[1,2-双(4-正烷氧基苯基)乙烷-1,2-二硫醇]镍,CnO–Ni(n=1–12,
14, 16, 18)已被合成。通过使用不同的扫描量热法、偏光显微镜、温度依赖性X射线衍射技术、电子光谱和循环伏安法,研究了它们的介晶性、热变色性、超分子结构和π受体性质。从X射线衍射和电子光谱结果来看,确定了CnO–Ni
复合物对于 n≤10 展现两种不同颜色的盘状层状(DL)介晶相,而 Cn–Ni 复合物均无介晶相,并且热变色性(棕色→绿色)归因于从 Ni–Ni 键合二聚体到
Ni–S 键合二聚体的缓慢转变。