Spin Crossover Behavior of Dinuclear Fe
II
Complexes with Bis‐Tetradentate Bridging‐Type Ligands
摘要:
AbstractThe preparation and characterization of two new FeII dinuclear complexes with bis‐tetradentate bridging‐type ligands [{Fe(NCS)2}2(L)]·DMF·2H2O (1: L = L1{2,5‐bis[N,N‐bis(2‐pyridylmethyl)aminomethyl]pyrazine}, 2: L = L2{2,3‐bis[N,N‐bis(2‐pyridylmethyl)aminomethyl]pyrazine}) are reported. Magnetic measurements reveal that complexes 1 and 2 exhibit different thermal spin‐crossover behavior. Complex 1 shows a crystalline solvent effect on spin crossover (SCO). After desorption of the crystalline solvent by heating, an abrupt one‐step transition with a hysteresis loop was observed for the desolvated form 1′. Conversely, a gradual two‐step SCO was obtained for 2. The photomagnetic effect was also investigated in 1′ and 2, and both complexes clearly show light‐induced excited spin state trapping. Interestingly, one‐step and two‐step thermal relaxation were observed for 1′ and 2, respectively. Such different SCO properties occur because of the cooperative effects owing to the structure of the ligand.
醌在有机合成和生物系统中是众所周知的有机氧化剂,但是与n型有机半导体相关的电子接受能力却很少得到开发。在这里,我们报告了对两组π不足的并五苯醌,氟化并五苯醌和N-杂戊并苯醌的综合研究,重点介绍了它们的电子结构,分子堆积和n沟道薄膜晶体管。发现用F原子取代并五苯醌的H原子或用N取代C原子可以降低并五苯醌的最低未占据分子轨道(LUMO)能级,从而产生场效应迁移率高达0.1 cm以上的n型有机半导体。2 V -1 s -1在薄膜晶体管中。在两组醌的电子结构和分子堆积方面进行比较,得出了有趣的发现,即吸电子部分在调节前沿分子轨道和π堆积中的作用。关于分子堆积的另一个有趣发现是四重弱氢键,该氢键连接了相邻的醌π堆栈。这项研究表明,π缺乏的醌将是n型有机半导体的一般设计。
The Diels-Alderreactions of heterocyclic o-quinodimethanes, generated in situ from 6,7-disubstituted quinoxalino[2,3-d]-[1, 2lambda(4)]oxathiine 2-oxides (6a-c), 2,3-disubstituted-8, 9-dihydro-6H-8lambda(4)-[1,2]oxathiino[4,5-g]quinoxalin-8-one (7a-c) (sultines), and pyrazinosultine (22), with electron-poor olefins and [60]fullerene are described. The heterocyclic-fused sultines 7a-c and 22 are readily
Microwave-Enhanced Reactivity of Non-Activated Dienophiles Towards Pyrazine<i>o</i>-Quinodimethanes
作者:Angel Díaz-Ortiz、Antonio de la Hoz、Andrés Moreno、Pilar Prieto、Rafael León、María A. Herrero
DOI:10.1055/s-2002-35593
日期:——
Microwave irradiation in solvent-free conditions induces cycloaddition reactions of pyrazine o-quinodimethane intermediates with electron-rich dienophiles within 10-15 min to afford quinoxaline derivatives in acceptable yields.
Compounds of formula (I), wherein the substituents are as defined in claim (
1
), and the agrochemically acceptable salts and all stereoisomers and tautomeric forms of the compounds of formula (I) can be used as agrochemical active ingredients and can be prepared in a manner known per se.
Compounds of formula (I), wherein the substituents are as defined in claim (1), and the agrochemically acceptable salts and all stereoisomers and tautomeric forms of the compounds of formula (I) can be used as agrochemical active ingredients and can be prepared in a manner known per se.
Tuning the ambipolar performance: carefully designed N-heteropentacenes realized fine tuning of their HOMOs and LUMOs, which dramatically affected their ambipolar transport performance in field-effect transistors.