Site-selective homo- and hetero-metallic doping of a 1D Zn-based coordination polymer to enhance the dimensionality and photocurrent responses

Abstract

By utilizing the coordination unsaturation of 1,2,3-benzenetricarboxylate (1,2,3-BTA) and protonated N,N′-di(3-pyridyl)succinamide (L) in the as-synthesized 1D coordination polymer (CP) of [(H₂L)_0.5][Zn(1,2,3-BTA)(H₂O)]·2H₂O (1), we successfully doped an additional half equivalent of Zn²⁺ and Co²⁺ ions to yield [Zn₃L(1,2,3-BTA)₂(H₂O)₆]·4H₂O (2) and [Zn₂CoL(1,2,3-BTA)₂(H₂O)₆]·4H₂O (2c). Compounds 2 and 2c are also possible through direct one-pot metal–ligand assembly. With the one-pot method, [Zn_2.76Co_0.24L(1,2,3-BTA)₂(H₂O)₆]·4H₂O (2a) and [Zn_2.40Co_0.60L(1,2,3-BTA)₂(H₂O)₆]·4H₂O (2b) are accordingly prepared to demonstrate the universality of hetero-metallic doping and for probing the doping effect on photocurrent responses. Compounds 2, 2a–2c are 2D CPs formed by linking 1,2,3-BTA-based 1D chains through L ligands. Their photocurrent responses were found to be positively related to the Co²⁺ percentage of the doped materials.