Chirality and Polarity Modulation in Semiconductive Zinc(II) Coordination Polymers Containing Thiolate-Based Ligands

Inorg Chem. 2025 Mar 24;64(11):5755-5763. doi: 10.1021/acs.inorgchem.5c00577. Epub 2025 Mar 10.

Abstract

Recently, chiral semiconductors have attracted considerable attention owing to their potential applicability in optoelectronics and spintronics. In this study, homochiral and heterochiral semiconductive Zn(II) coordination polymers [Zn(tbbt)((X)-mba)2]·solvent (H2tbbt = 4,4'-thiobisbenzenethiol, mba = methylbenzylamine, X = R, S, rac) were systematically synthesized. Single-crystal X-ray diffraction analyses revealed that KGF-57(R) and KGF-57(S) (KGF = Kwansei Gakuin framework), of type [Zn(tbbt)((X)-mba)2]·(X)-mba, obtained from enantiopure (R)-mba and (S)-mba isomers, exhibited chiral-nonpolar homochiral one-dimensional (1D) structures with mba lattice solvents, comprising left- and right-handed helical chains, respectively. Conversely, when using (rac)-mba, two heterochiral 1D architectures were obtained depending on synthetic temperature and solvent. Specifically, KGF-57(rac) of type [Zn(tbbt)((rac)-mba)2]·(rac)-mba·nH2O exhibited an achiral-nonpolar heterochiral 1D structure with (rac)-mba and H2O lattice solvents, containing alternately aligned left-handed helical chains with (R)-mba and right-handed helical chains with (S)-mba. Conversely, KGF-58(rac) with the formula [Zn(tbbt)((rac)-mba)2] formed an achiral-polar assembly without mba lattice solvents. This structure is composed of zigzag chains with either (R)-mba or (S)-mba in a heterochiral arrangement. Time-resolved microwave conductivity measurements and first-principles calculations revealed that a series of Zn(II) coordination polymers exhibited photoconductivity originating from the Zn-thiolate-based skeleton. Furthermore, by exchanging the mba ligands coordinated to 1D Zn-thiolate chains, a reversible structural conversion accompanied by chirality and polarity variation was achieved.