Syntheses, Structural Characterization, and Properties of Mixed‐valent Co II Co III and Zn II Coordination Polymers from 5‐(4‐Carboxybenzylamino)isophthalic Acid

The reaction of cobalt(II) and zinc(II) salts with 5‐(4‐carboxybenzylamino)isophthalic acid (H 3 L) in the presence of 1,2‐bis(pyridin‐4‐yl)ethane (bpa) as auxiliary co‐ligand under hydrothermal synthetic condition led to the formation of two complexes, {[(Co II ) 0.25 (Co III ) 0.5 (HL)(H 2 O) 0.5 (bpa) 0.25 ] · 2.5H 2 O} n ( 1 ) and [Zn(HL)(bpa) 0.5 ] n ( 2 ), which were characterized by single crystal and powder X‐ray diffraction, IR spectroscopy as well as elemental and thermogravimetric analyses. Complex 1 displays uninodal 4‐connected 2D sql network with (4 4 .6 2 ) topology, complex 2 is binodal (3, 6)‐connected 2D (4.6 2 ) 2 (4 2 .6 10 .8 3 ) network. Interestingly, complex 1 shows structural features consistent with the Jahn‐Teller distortions, whereas in 2 adjacent 2D networks are interpenetrated to show 2D + 2D → 3D parallel interpenetration of slabs. Furthermore, it is noteworthy that the oxidation of Co II to Co III occurred in the preparation of 1 to give rise to a mixed‐valent cobalt coordination polymer, which can be confirmed by magnetic measurement. Magnetic property of 1 and luminescence of 2 were investigated.