A Chiral Metal-Organic 1D-Coordination Polymer Upon Complexation of Phenylene-Bridged Bipyrrole and Palladium (II) Ion

Kumiko Nishinaka; Jiandong Han; Dongli Han; Yue Liu; Yanqing Du; Meiling Wang; Chaolu Eerdun; Nobuyasu Naruse; Yutaka Mera; Yoshio Furusho; Akihiko Tsuda

doi:10.3389/fchem.2020.613932

A Chiral Metal-Organic 1D-Coordination Polymer Upon Complexation of Phenylene-Bridged Bipyrrole and Palladium (II) Ion

Front Chem. 2020 Dec 1:8:613932. doi: 10.3389/fchem.2020.613932. eCollection 2020.

Authors

Kumiko Nishinaka¹, Jiandong Han², Dongli Han², Yue Liu¹, Yanqing Du², Meiling Wang², Chaolu Eerdun², Nobuyasu Naruse³, Yutaka Mera³, Yoshio Furusho³, Akihiko Tsuda^{1

2

3}

Affiliations

¹ Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan.
² Department of Pharmaceutical Sciences, Inner Mongolia Medical University, Hohhot, China.
³ Department of Chemistry, Shiga University of Medical Science, Otsu, Japan.

Abstract

Metal-organic 1D-coordination polymers, having unique electronic and optical properties, are expected to be a novel advanced functional material capable of fabricating smart plastics, films, and fibers. In this study, we have synthesized a novel metal-organic 1D-coordination polymer composed of a phenylene-bridged bipyrrole bearing N-alkylimino groups (BPI) and palladium(II) ion. The BPI and Pd(II) form square planar bis(bidentate) complex to form a metal coordinated π-conjugation polymer (Poly-BPI/Pd). It is stable in solutions at room temperature, and allowed measurement of its average molecular weight in SEC (M _w = 106,000 and M _n = 18,000, M _w/M _n = 5.88). It also provided a reversible multi redox profile in cyclic voltammetry, most likely originating from strong π-electronic interactions between the BPI components via Pd ion. A variety of substituent groups can be attached to the imino-nitrogens of BPI. A coordination polymer composed of a BPI derivative bearing chiral alkyl chains and Pd(II) showed strong circular dichroism (CD) in the solution due to the unidirectional chiral conformation of the BPI components in the polymer backbone.

Keywords: chirality; complex; coordination polymer; helical polymer; π-conjugation.