N , N ′-二烷基-1,4-苯二甲酰胺(CnIPA )的简单分子形成一维(1D)N-H⋯O氢键分子组装体,通过部分熔化显示出固固相变烷基链在相变之前变为各向同性液体而不形成液晶相。CnTPA的相变、分子组装结构、介电常数和铁电性通过改变–CONHC n H 2 n +1到n的烷基链长度 ( n ) 来评估= 5-16, 18。一维氢键结构进一步组装成烷基链的双层排列,形成层状分子组装体,其中两条烷基链的部分熔化发生在高T固相。在CnTPA的相变行为和T相关介电常数中观察到奇偶效应,其中偶数导数比奇数导数具有更大的运动自由度。介电响应与 N-H⋯O氢键的极性结构单元的运动自由度相关,其动力学在相变到高T后在T范围内被激活固相。在n ≥ 11 的CnTPA的铁电极化 - 电场 ( P - E ) 磁滞曲线中观察到 N-H ⋯ O氢键链的集体偶极反转。固相辅助 N-H⋯O单元的偶极反转形成氢键铁电体。
Diurea derivatives useful as medicaments and processes for the
申请人:Yamanouchi Pharmaceutical Co., Ltd.
公开号:US05091419A1
公开(公告)日:1992-02-25
Diurea derivatives are provided which are represented by the following general formula and salts thereof: ##STR1## The above compounds inhibit acyl-coenzyme A cholesterol acyl-transferase (ACAT enzyme), and thereby control the accumulation of cholesterol ester on the smooth muscle of arterial wall in the blood vessels.