A homologous series of silver complexes of 1-alkylimidazoles (R-im, R = CnH2n+1, where n
= 10, 12, 14, 16 and 18) was synthesized. All the CnH2n+1-im ligands are non-mesomorphic. Upon complexation, all the [Ag(CnH2n+1-im)2][NO3], except for n
= 10, exhibit liquid crystalline properties. The crystal structure of [Ag(C12H25-im)2][NO3] shows that the silver center is two-coordinate and adopts a U-shaped conformation with bilayer packing. The non-mesomorphic [Ag(C16H33-bim)2][NO3]
(bim = benzimidazole) has a three-coordinate silver ion and has a chair conformation with monolayer stacking. Non-mesomorphic [Ag(C16H33-bim)2][BF4] has a linear geometry around the silver ion and also has a chair conformation. The mesophase for the Ag–(CnH2n+1-im) complexes has been identified as the smectic A (SmA) phase. [Ag(C16H33-im)2]+ with four different anions, NO3−, BF4−, PF6− and CF3SO3− were compared. Of the four Ag–im complexes, only that with the CF3SO3− anion does not show liquid-crystal behavior.
合成了一系列同源的1-烷基
咪唑银配合物(R-im,R = CnH2n+1,其中n = 10,12,14,16和18)。所有CnH2n+1-im
配体均为非介晶性。在复合时,除了n = 10的以外,所有的[Ag(CnH2n+1-im)2][ ]都表现出液晶特性。[Ag(
C12H25-im)2][ ]的晶体结构表明
银中心为二配位,采用U形构象并呈双层堆积。非介晶性的[Ag(
C16H33-bim)2][ ](bim =
苯并咪唑)具有三配位的
银离子,并且呈现单层堆积的椅子构象。非介晶性的[Ag( -bim)2][ ]在
银离子周围有线性几何构型,同样也呈椅子构象。Ag–(CnH2n+1-im)配合物的相态已被确定为SmA相。比较了[Ag( -im)2]+与四种不同阴离子,
NO3−、
BF4−、PF6−和CF3SO3−。在四种Ag–im配合物中,只有与CF3SO3−阴离子结合的配合物未显示液晶行为。