Structural Diversity of Zinc(II), Manganese(II), and Gadolinium(III) Coordination Polymers Based on Two Isomeric N-Heteroaromatic Polycarboxylate Ligands: Structures and Their Derived Mn2O3 for Lithium Storage Applications.

Tuning the coordination sites of two isomeric semirigid ligands, 5-(4-pyridin-3-yl-benzoylamino)isophthalic acid (3-H2PBI) and 5-(4-pyridin-4-yl-benzoylamino)isophthalic acid (4-H2PBI), afforded six new coordination polymers (CPs), [Zn(3-PBI)(H2O)]n (1), {[Mn2(3-PBI)2(H2O)]·DMF·2H2O}n (2), {[Gd2(3-PBI)3(H2O)3]·DMF·3H2O}n (3), {[Zn2(4-PBI)2]·H2O}n (4), {[Mn2(4-PBI)2(H2O)2]·4H2O}n (5), and {(Me2NH2)[Gd(4-PBI)2]·H2O}n (6). Structural analysis shows that 1 consists of 2D honeycomb (6,3) net, three sets of networks interlace mutually, generating an unexpected 2D + 2D + 2D → 3D polycatenating interesting system. 2 exhibits a 3D pcu topology. 3 presents a unique 3D with 3,3,6T13 network topology. 4 possesses 3D 2-fold interpenetrated structure with rutile topology. 5 presents an alluring 2D architecture comprising two distinct topologies (kgd and hcb), stacked arrangement in an unexpected ABBABB mode. 6 displays 2D (4,4)-grid network. A differentiation of these structural features indicate that coordination connectivity of metals, together with binding modes of two ligands are accountable for the fascinating structural contrast. In addition, 2 and 5 were then transformed into Mn2O3 via a simple heat treatment. Electrochemical test results show that both of the obtained Mn2O3 moieties exhibit stable lithium storage properties and excellent rate capabilities.