基于三氰合多吡唑硼酸铁的电子转移化合物的设计与合成

The Design and Synthesis of Electron Transfer Complexes Based on Tricyanopyrazolylborateferrate

孟玲祎

11749054

硕士

化学

张元竹

2019-05-21

2019-07-09

哈尔滨工业大学

深圳

近年来，低维铁-钴普鲁士蓝类化合物（PBAs）因其结构易于调控且表现出可逆的热致、光致磁转变行为而备受关注。该类化合物中存在两个不同的稳态：[FeIIILS(µ-CN)CoIIHS]和[FeIILS(µ-CN)CoIIILS]，通过温度改变或低温下的光激发诱导电子在Fe和Co之间转移而实现两个稳态之间的转换。氰根化合物的构筑块原则为研究该类化合物的结构-物性关系提供了一系列模型化合物。金属中心的配位环境、分子间相互作用力（氢键和π-π相互作用）及溶剂分子均可以影响该类化合物的电子转移特性。本文基于研究较为透彻的[Fe2Co2]平面四方簇合物体系，通过引入含有活泼醛基的辅助配体4’-甲基-2,2’-联吡啶-4-甲醛，合成了一例具有平面四方结构的化合物{[(Tp*)Fe(CN)3Co(bpyCHO)2]2[ClO4]2}2CH3CNH2O (1)，基于希夫碱反应，发展了两条简单有效地控制目标分子中电子转移特性的合成策略：首先，引入具有不同碳链长度的有机单胺(NH2CnH2n+1，n=1-4)，利用易于操作的希夫碱反应，合成一系列二联吡啶衍生物(bpyC=NR)，通过定向合成策略构筑四方骨架的[Fe2Co2]化合物2-5：{[(Tp*)Fe(CN)3Co(bpyC=NMe)2]2[ClO4]2}2CH3CN2H2O (2)、[(Tp*)Fe(CN)3Co(bpyC=N(n-Pr))2]2[ClO4]2 (3)、[(Tp*)Fe(CN)3Co(bpyC=N(i-Pr))2]2[ClO4]2 (4)、[(Tp*)Fe(CN)3Co(bpyC=N(n-Bu))2]2[ClO4]2 (5)。初步磁性测试表明化合物1没有电子转移行为而甲胺修饰的化合物2存在部分电子转移特性。通过引入不同碳链的有机双胺(NH2CnH2nNH2，n=5, 7, 9, 11)，利用简单易行的希夫碱反应，合成联吡啶衍生物bpyC=N(CH2)nN=Cbpy，通过定向合成策略构筑新型铁-钴电子转移化合物(Capsule) 6-10：{[(Tp*)Fe(CN)3Co(bpy2N5)2]2[ClO4]2}6DMF (6)、{[(Tp*)Fe(CN)3Co(bpy2N7)2]2[ClO4]2}6DMF (7)、{[(Tp3,Me)Fe(CN)3Co(bpy2N7)2]2[ClO4]2}8DMF (8)、{[(Tp3,Me)Fe(CN)3Co(bpy2N9)2]2[ClO4]2}2MeCN2Et2O2H2O (9)、{[(Tp*)Fe(CN)3Co(bpy2N11)2]2[ClO4]2}5MeCN (10)。通过对化合物6-10进行初步的磁性表征和变温红外测试，发现化合物6-10均存在热致电子转移现象。化合物6、9、10存在部分电子转移行为，化合物7具有两步电子转移行为，化合物8发生了一步完全的电子转移且具有较高的转变温度，T1/2约为316 K。变温单晶数据与磁性测试结果相吻合，但是具体的机理仍在探索中。

Fe/Co Prussian blue analogues (PBAs) have attracted continuous attention in recent yaers due to their tunable optical and magnetic behaviors associated with thermally and optically induced electron transfer between the FeIILS-CN-CoIIILS (LS = low spin) linkages and FeIIILS-CN-CoIIHS linkages (HS = high spin). A series of zero dimensional model clusters were designed and constructed through brick and mortar building block methods to further investigate the magneto-structural correlation. The charge transfer behavior was found to be sensitive to the the redox potentials of metal centers, which can be affected by the coordination environment of metal centers, intermolecular interactions (hydrogen bonds and π-π stacking) and the lattice solvents. However, there are still many challenges to be addressed, such as how to regulate the transition temperature and rate of thermal induced electron transfer precisely; how to stabilize and increase the lifetime of the light-induced excited state; how to achieve the multi-step charge transfer behavior or introduce another functionality into this system.We are focusing on a new project based on the well-known [Fe2Co2] square system by introducing convenient functional groups, such as aldehyde group, into 2, 2′-bipyridine (4-formyl-4′-methyl-2,2′-bipyridine, bpyCHO), which may further react with amines:A series of [Fe2Co2] square complexes ({[(Tp*)Fe(CN)3Co(bpyCHO)2]2[ClO4]2}2CH3CNH2O (1), {[(Tp*)Fe(CN)3Co(bpyC=NMe)2]2[ClO4]2}2CH3CN2H2O (2), [(Tp*)Fe(CN)3Co(bpyC=N(n-Pr))2]2[ClO4]2 (3), [(Tp*)Fe(CN)3Co(bpyC=N(i-Pr))2]2[ClO4]2 (4), [(Tp*)Fe(CN)3Co(bpyC=N(n-Bu))2]2[ClO4]2 (5)) were synthesized based on the bipyridine derivatives (bpyC=NR) obtained by the simple Schiff base reaction between bpyCHO and monoamines (NH2CnH2n+1, n=1-4). No electron transfer behavior is observed in compound 1, while the methylamine-modified complex 2 has partial electron transfer.A series of novel [Fe2Co2] square complexes (Capsule) ({[(Tp*)Fe(CN)3Co(bpy2N5)2]2[ClO4]2}6DMF (6), {[(Tp*)Fe(CN)3Co(bpy2N7)2]2[ClO4]2}6DMF (7), {[(Tp3,Me)Fe(CN)3Co(bpy2N7)2]2[ClO4]2}8DMF (8), {[(Tp3,Me)Fe(CN)3Co(bpy2N9)2]2[ClO4]2}2MeCN2Et2O2H2O (9), {[(Tp*)Fe(CN)3Co(bpy2N11)2]2[ClO4]2}5MeCN (10)) were obtained in a similar way to complexes 1-5, by using the diamine bipyridine derivatives (bpyC=N(CH2)nN=Cbpy). Magnetic studies indicated distinct charge transfer behavior for 6-10. Specifically, complex 8 has a full electron transfer and T1/2 is about 316 K, while complexes 6, 9 and 10 exhibit partial electron transfer behavior. A two-step electron transfer behavior was observed for complex 7. Variable-temperature single-crystal diffractions were further measured, which were in consistent with the magnetic analysis.

磁性双稳态 电子转移 氰根桥联

magnetic bistability electron transfer cyano-bridged

中文

联合培养

南方科技大学

孟玲祎. 基于三氰合多吡唑硼酸铁的电子转移化合物的设计与合成[D]. 深圳. 哈尔滨工业大学,2019.