Pillar-template strategy switching the redox activity and magnetic properties of trisphenylamine-based coordination polymers

• Published in: CrystEngComm 2020-05, Vol.22 (18), p.3155-3163
• Main Authors: Qiu, Ya-Ru, Li, Bang, Zhou, Yan, Su, Jian, Ge, Jing-Yuan
• Format: Article
• Language: English
• Subjects: Coordination polymers; Hydrothermal crystal growth; Magnetic properties; Oxidation; Single crystals; Terephthalic acid
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/d0ce00256a

It is an efficient approach to exploit a pillaring and templating strategy for creating varieties of functionalized coordination polymers (CPs). Four novel CPs incorporating single metal nodes and a redox-active tris(4-(pyridine-3-yl)phenyl)amine ligand ( m -NPy 3 ) have been prepared by a hydrothermal method. Compounds 1-3 , [M( m -NPy 3 )(NO 3 ) 2 ·CH 3 OH] n (M = Co for 1 , Ni for 2 , and Zn for 3 ), are isomorphous two-dimensional (2D) layered CPs. Compound 4 , [Co( m -NPy 3 )(TPA) 0.5 Cl·CH 3 OH] n (TPA = bidentate terephthalic acid), is a three-dimensional (3D) CP, which is pillared by linear bidentate terephthalic acid (TPA) linkers. Notably, with the presence of TPA, the layered compound 1 can be further assembled to the 3D pillared-layer architecture 4 by single-crystal-to-single-crystal (SC-SC) transformation. All the compounds were characterized and the redox activity of trisphenylamine is maintained in all four CPs proven by solid-state cyclic voltammetry. Compared with 1 , the location of the first oxide peak in 4 shows a reduction of nearly 0.14 V vs. Fc/Fc + . The magnetic study shows that the pillared-layer 4 exhibits a typical field-induced single-ion magnet property with a higher energy barrier (13.1 K) than 1 (5.1 K). A pillar-template strategy was used to modify the redox activity and magnetic properties of trisphenylamine-based coordination polymers via a single-crystal-to-single-crystal transformation method.