摘要
通过1-庚烷基-1H-咪唑-2-甲醛(L^1)、1-十四烷基-1H-咪唑-2-甲醛(L2)、1-十六烷基-1H-咪唑-2-甲醛(L3)、1-十八烷基-1H-咪唑-2-甲醛(L4)、1-二十烷基-1H-咪唑-2-甲醛(L5)分别和四氟硼酸亚铁与1-苯乙胺反应一步法合成了配合物1~5。利用红外光谱(IR)、元素分析(EA)手段对1~5进行表征。配合物1的X射线单晶衍射结构研究表明,每个结构基元中包含1个[Fe(L^1)3]^2+阳离子和2个四氟硼酸根阴离子。铁(Ⅱ)金属中心与3个配体上的6个N原子配位,形成面式八面体单核化合物。Fe(Ⅱ)-N键长表明配合物1中的Fe(Ⅱ)在173 K时处于低自旋状态。在[Fe(L^1)3]^2+中,相邻配体中的苯环和咪唑环形成分子内π-π相互作用;[Fe(L^1)3]^2+进一步通过烷基链与芳香环之间的C-H…π相互作用形成超分子网络结构。磁性测试表明,配合物1表现出不完全的自旋交叉性能,转换温度为341 K;2为高自旋顺磁性化合物,3~5则表现出不完全的自旋交叉行为。以具有较长烷基链的配合物2~5作为凝胶因子,环己烷作为溶剂可形成对应的金属有机凝胶MOG2~MOG5。扫描电子显微镜(SEM)图片显示MOG2~MOG5凝胶都具有三维网络状孔隙结构。MOG2~MOG5表现出可逆的凝胶-溶胶转变,在热和机械力的作用下,MOG2~MOG5金属有机凝胶迅速转变为溶胶状态,且静置后能够恢复至凝胶状态,表现出良好的刺激响应性和自修复能力。
Complexes 1~5 were synthesized by one-step reaction of 1-heptyl-1H-imidazole-2-carboxaldehyde(L^1),1-tetradecyl-1H-imidazole-2-carbaldehyde(L2),1-hexadecyl-1H-imidazole-2-carbaldehyde(L3),1-octadecyl-1H-imidazole-2-carboxaldehyde(L4),1-eicosyl-1H-imidazole-2-carboxaldehyde(L5)with ferrous tetrafluoroborate and 1-phenylethylamine,respectively.The five complexes have been determined by IR spectra and elemental analysis.X-ray crystallography reveals that each unit in 1 contains one[Fe(L^1)3]^2+cation and two BF4-anions.The iron(Ⅱ)center coordinates with six N donor atoms from three ligands to form a octahedral mononuclear compound with fac-configuration.The Fe(Ⅱ)-N bond distances indicate that the Fe(Ⅱ)sites of 1 are in low-spin state.As for[Fe(L^1)3]^2+,intramolecularπ-πinteractions are present between phenyl group and imidazole ring of an adjacent ligand,and then a supramolecular architectures are further formed by C-H…πinteractions between alkyl chain and aromatic ring.Magnetic measurements reveal that 1 displays incomplete spin-crossover behaviour at 341 K,and 2 is a high-spin paramagnetic compound,while 3~5 show incomplete spin-crossover behaviour.The corresponding metallogels MOG2~MOG5 were formed by using complexes 2~5 with longer alkyl chains as gelator and cyclohexane as solvent. Scanning electron microscopy(SEM) images showed that the MOG2~MOG5 had 3D network pore structure. Reversible gel-sol transitions were found in MOG2~MOG5. Under the influence of heat and mechanical force, MOG2~MOG5 were rapidly converted to sol, which can be restored to gel after being stationary, showing good stimulation-response and self-healing ability. CCDC: 1920725, 1.
作者
王娅琴
张海霞
张舒恒
何威
葛芳圆
陈雨欣
顾志国
WANG Ya-Qin;ZHANG Hai-Xia;ZHANG Shu-Heng;HE Wei;GE Fang-Yuan;CHEN Yu-Xin;GU Zhi-Guo(School of Chemistry and Material Engineering,Jiangnan University,Wuxi,Jiangsu 214122,China;Key Laboratory of Synthetic and Biological Colloids,Ministry of Education,Wuxi,Jiangsu 214122,China)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2019年第12期2260-2268,共9页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.21771089)
中央高校基本科研业务经费(No.JUSRP21936,JUSRP51725B)资助项目