Molecule-based valence tautomeric bistability synchronized with a macroscopic crystal-melt phase transition
Molecule-based valence tautomeric bistability synchronized with a macroscopic crystal-melt phase transition
复制标题
DOI：
10.1021/ja711268u
复制
发表时间：
2008-04-23
影响因子：
15
通讯作者：
Kitagawa, Susumu
中科院分区：
文献类型：
--
作者：
Kiriya, Daisuke;Chang, Ho-Chol;Kitagawa, Susumu
在这里，我们展示了价互变异构（VT）分子相互转化的同步双稳定性和长烷氧基功能化钴-二氧羰基配合物的宏观晶体-熔体相变。研究了一系列新的配合物，[Co(CnOPY)(2)(3,6- dtbq)(2)]（3,5-二氧基（CnH2 On+1-; n = 9,12和17）吡啶（CnOPY）和3,6-二叔丁基半醌酸酯或儿茶酚酸配体（3,6- dtbq））。所有配合物均表现为分子VT相互转化，并存在由晶体-熔体同步相变引起的热滞后。热力学分析表明，在50 K以上，分子VT相互转化受到限制，而在50 K左右，共时性加速了晶体-熔体相变。这种同步性是由一种互变异构体的结晶相和另一种互变异构体的熔融相中烷氧基链的焓和熵效应引起的。我们的研究结果显示了有效的化学和热力学策略来结合基于分子和宏观的双稳定性。
Here, we show a synchronic bistability of valence tautomeric (VT) molecular interconversion and a macroscopic crystal-melt phase transition in long alkoxy-functionalized cobalt-dioxolene complexes. Studies have been carried out for a novel series of complexes, [Co(CnOPY)(2)(3,6-DTBQ)(2)] (3,5-dialkoxy(CnH2 On+1-; n = 9, 12, and 17)pyridine (CnOpy) and 3,6-di-tert-butyl semiquinonate or catecholate ligands (3,6-DTBQ)). All complexes show the molecular VT interconversion with thermal hysteresis attributed to the synchronous crystal-melt phase transition. Thermodynamic analysis has revealed that the molecular VT interconversion is restricted over 50 K and crystal-melt phase transition is accelerated about 50 K by the synchronicity. The synchronicity is attributed to enthalpic and entropic effects of the alkoxy chains in the crystalline phase of the one tautomer and the melt phase of the other, respectively. Our results show efficient chemical and thermodynamic strategies to combine molecule-based and macroscopic bistabilities.