An efficient, redox-enhanced pair of hydrogen-bond tweezers for chloride anion recognition, a key synthon in the construction of a novel type of organic metal based on the secondary amide-functionalized ethylenedithiotetrathiafulvalene, β"-(EDT-TTF-CONHMe)2[Cl • H2O]
An efficient, redox-enhanced pair of hydrogen-bond tweezers for chloride anion recognition, a key synthon in the construction of a novel type of organic metal based on the secondary amide-functionalized ethylenedithiotetrathiafulvalene, β"-(EDT-TTF-CONHMe)2[Cl • H2O]
复制标题
DOI：
10.1021/cm000143k
复制
发表时间：
2000-07-01
影响因子：
8.6
通讯作者：
Jérome, D
中科院分区：
文献类型：
--
作者：
Heuzé, K;Mézière, C;Jérome, D
氧化还原活性仲酰胺3-甲酰胺基-3 ′，4 ′-亚乙基二硫代四硫富瓦烯（EDT-TTF-CONHMe 1）的1，1，2-三氯乙烷溶液在硅胶上负载的n-Bu 4 NF存在下电结晶，得到混合价氯盐，式（1）（2）[Cl . H2O]，通过元素分析和X射线晶体结构解析。氯阴离子和水分子在同一位点上是无序的，并且通过两个强氢键与π-供体分子配位，所述两个强氢键涉及酰胺邻位的ammonium N-H和芳香族C-H基团，从而使一对坚固的镊子状环状基序合格。在溶液中也观察到这种有效的阴离子识别效应，如通过N-H和C-H氢原子共振的H-1 NMR低场位移以及通过Cl-络合后氧化电位1的阴极位移所证明的，确定实际电结晶物质是溶剂化的阴离子氯化物络合物[（1 . Cl-）（H2O），1而不是游离酰胺。（1）（2）[Cl . H2O]采用层状β“型结构，具有疏水性（EDT-TTF）和亲水性（酰胺、Cl-、H2O）片段的分离。施主层的HOMO-HOMO分子间相互作用能大，费米面表现出明显的二维特征。在120 K以下观察到的EPR Dysonian线表明了一个高导电系统，通过120 S cm（-1）的高室温电导率和低至0.47 K的金属行为得到证实，电导率增加了167倍，但没有迹象表明过渡到超导状态，这可能是Cl-/H2O无序的结果。
Electrocrystallization of 1,1,2-trichloroethane solutions of the redox-active secondary amide, 3-methylamido-3',4'-ethylenedithiotetrathiafulvalene (EDT-TTF-CONHMe 1) in the presence of n-Bu4NF supported on silica gel afforded a mixed-valence chloride salt, formulated (1)(2)[Cl . H2O] from elemental analysis and X-ray crystal structure resolution. The chloride anion and water molecule are disordered on the same site, and coordinated to the pi-donor molecule by two strong hydrogen bonds involving the amidic N-H and the aromatic C-H group ortho to the amide, thereby qualifying a robust pair of tweezers-like cyclic motif. This efficient anion recognition effect is also observed in solution, as demonstrated by H-1 NMR downfield shifts of both the N-H and C-H hydrogen atom resonances, as well as by a cathodic shift of the oxidation potential of 1 upon Cl- complexation, establishing that the actual electrocrystallized species is a solvated anionic chloride complex [(1 . Cl-)(H2O),1 rather than the free amide. (1)(2)[Cl . H2O] adopts a layered beta "-type structure with segregation of the hydrophobic (EDT-TTF) and hydrophilic (amide, Cl-, H2O) fragments. The HOMO-HOMO intermolecular interaction energies for the donor layers are large and the Fermi surface exhibits a pronounced two-dimensional character. The EPR Dysonian line observed below 120 K indicates an highly conducting system, confirmed by high room-temperature conductivity of 120 S cm(-1) and metallic behavior down to 0.47 K, with a 167-fold increase of the conductivity, but no indication however of a transition to a superconducting state, a likely consequence of the Cl-/H2O disorder.