Two new Co(II) coordination polymers based on redox-active ligands: Structure, Chromism and Magnetism

By utilizing redox-active ligands [monoquaternized 4,4'-bipyridines (monoquats) and naphthalene diimide derivatives] and dicyanamide (dca) bridges, two new Co(II) complexes, [Co(dca)(2)(DPNDI)]n center dot 2nDMF center dot nH(2)O (1) and [Co(EQ)(2)(dca)(2)]nI(2)n center dot 4nH(2)O (2), have been synthesized (DPNDI = N,N'-di(3-pyridyl)-1,4,5,8-naphthalene tetracarboxydiimide, EQI = 1-ethyl-4-(4-pyridyl) pyridinium iodide). Complex 1 is a 2D network where 1D chains of [Co(dca)(2)](n) are linked by DPNDI ligands to form 2D layers. In complex 2, 1D chains of [Co(EQ)(2)(dca)(2)](n) cross vertically. Interestingly, complex 1 is photochromic while complex 2 is both photoand thermochromic. Moreover, their magnetic properties have also been investigated. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Two new Co(II) complexes with different structures and properties have been synthesized in this study. One of the complexes is photochromic, while the other complex exhibits both photochromic and thermochromic properties. Moreover, these complexes also possess unique magnetic properties.