Electrostatic structural enforcement in low-dimensional solids. Synthesis, structure, and electronic properties of polycationic ruthenium complexes with polycyanoanions
Electrostatic structural enforcement in low-dimensional solids. Synthesis, structure, and electronic properties of polycationic ruthenium complexes with polycyanoanions
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低维固体中的静电结构强化。
DOI：
10.1021/ja00187a025
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发表时间：
1989
影响因子：
15
通讯作者：
David C. Johnson
中科院分区：
文献类型：
--
作者：
M. Ward;P. Fagan;J. Calabrese;David C. Johnson
(Cp* Ru) 2 (>; 6, 7? 6-[22](1, 4) cyclophane) 2+(D+-D+) 和 [Cp* Ru (77-C6H5)] 4E4+((D+) 4E: E= C, Si) 证明聚阳离子在结构上增强了固态结构，阴离子采用反映电荷空间分布的堆叠图案。聚阳离子。单核 D+ 阳离子与 TCNQ™（TCNQ= 四氰基醌二甲烷）形成二晶型，经验式为 [D+][TCNQ™]。其中一相 (1) 结晶为阳离子和 TCNQ™ 阴离子的一维混合堆叠，而另一相 (2) 具有离散的 D+ A" A™ D+ 单元，且 (TCNQ) 22™ x-二聚体位于两个阳离子之间。未观察到 TCNQ™ 阴离子相当常见的分离堆积图案。然而，棒状 D+-D+ 阳离子中的钌中心提供了结构强化在 [D+-D+][(TCNQ), 2™](3, x= 2; 4, x= 4) 中提供不同的结构基序，通过在 0.1 V 阳离子存在下电化学还原 TCNQ（相对于 Ag/AgCl）制备，具有具有交替阳离子和 (TCNQ) 22™ x-二聚体的混合堆叠线性链，即...D+-D+ A™。 A'D+-D+ A™ 一个“...主题。相比之下，4在比(tcnq/tcnq-)更正的电势下，通过在阳离子存在下缓慢电化学还原TCNQ而结晶为导电黑色平行六面体，并具有两个平行于阳离子长轴的晶体学上独特的TCNQ堆叠。 D+-D+ 中的阳离子 Ru 位点之间的距离可容纳四个带有 (2-) 电荷的 TCNQ 分子；所得混合价 p= 0.5 堆叠的室温电导率为 0.2™ 1 cm™ 1。非导电电荷转移盐 [D+-D+][C3 [C (CN) 2] 3™| 的固态结构2 (5) 和 [(D+) 4E][C3 [C (CN) 2] 3™] 4-xMeNO2 (6, E= C, x= 6; 7, E= Si, x= 4) 表现出 C3 [C (CN) 2] 3™ 阴离子的直链。对于5，阴离子堆叠轴平行于四阳离子，而6和7具有相互正交的阴离子堆叠，这些阴离子堆叠平行于由四阳离子中两对阳离子中心定义的正交轴排列。 4 的磁化率和 EPR 数据表明存在比单线基态高 0.08 eV 的能量可接近的三线态，且场分裂常数为零| Z)]= 66 G 和 \E\= 11 G。5-7 的 EPR 谱也表明存在能量可接近的三重态物质。然而，磁化率测量表明阴离子自旋存在强烈的反铁磁耦合，表明这些三重态物质是由于杂质或晶体缺陷造成的。
(Cp* Ru) 2 (>; 6, 7? 6-[22](1, 4) cyclophane) 2+(D+-D+), and [Cp* Ru (77-C6H5)] 4E4+((D+) 4E: E= C, Si) demonstrate that the polycations structurally enforce the solid-state structure, with anions adopting stacking motifs that reflect the spatial distributionof charge in the polycations. The mononuclear D+ cation forms dimorphs with TCNQ™(TCNQ= tetracyanoquinodimethane) with the empirical formula [D+][TCNQ™]. One of these (1) crystallizes with 1-D mixed stacks of cations and TCNQ™ anions, whereas the other phase (2) possesses discrete D+ A" A™ D+ units with a (TCNQ) 22™ x-dimer situated between two cations. Segregated stacking motifs that are rather common for the TCNQ™ anion are not observed. However, structural enforcement provided by the ruthenium centers in the rod-shaped D+-D+ dication affords different structural motifs in [D+-D+][(TCNQ), 2™](3, x= 2; 4, x= 4). Nonconducting 3, prepared by electrochemical reduction of TCNQ in the presence of the dication at-0.1 V (vs. Ag/AgCl), possesses mixed stack linear chains with alternating cations and (TCNQ) 22™ x-dimers, ie, a... D+-D+ A™ A'D+-D+ A™ A “... motif. In contrast, 4 crystallizes as conductive black parallelepipeds by slow electrochemical reduction ofTCNQ in the presence of the dication at potentials more positive than£(tcnq/tcnq-) and possesses two crys-tallographically unique TCNQ stacks parallel to the long axes of the cations. The distance between cationic Ru sites in D+-D+ accommodates four TCNQ molecules with an overall (2-) charge; the resultant mixed valent p= 0.5 stacks afford a room temperature conductivity of 0.2™ 1 cm™ 1. The solid-state structures of the nonconducting charge-transfer salts [D+-D+][C3 [C (CN) 2] 3™| 2 (5) and [(D+) 4E][C3 [C (CN) 2] 3™] 4-xMeN02 (6, E= C, x= 6; 7, E= Si, x= 4) exhibit linear chains of C3 [C (CN) 2] 3™ anions. For 5, the anion stacking axis is parallel to the dications, whereas 6 and 7 possess mutually orthogonal anion stacks that are aligned parallel to the orthogonal axes defined bytwo pairs of cationic centers in the tetracations. Magnetic susceptibility and EPR data for 4 indicate the presence of an energetically accessible triplet state 0.08 eV above thesinglet ground state with zero field splitting constants| Z)]= 66 G and\E\= 11 G. The EPR spectra of 5-7 also indicate the presence of energetically accessible triplet species. However, magnetic susceptibility measurements indicate strong antiferromagnetic coupling of the anion spins, suggesting that these triplet species are due to impurities or crystalline defects.