Semiconducting Coordination Polymers Based on the Predesigned Ternary Te-Fe-Cu Carbonyl Cluster and Conjugation-Interrupted Dipyridyl Linkers

5 years ago

Semiconducting Coordination Polymers Based on the Predesigned Ternary Te-Fe-Cu Carbonyl Cluster and Conjugation-Interrupted Dipyridyl Linkers

Chih-Chiang Shen, Chung-Yi Huang, Minghuey Shieh, Chang-Hung Kung, Chia-Yeh Miu, Chia-Chi Yu, Hsiang-Lin Liu, Yu-Hsin Liu

A series of semiconducting cluster-incorporated Cu-based coordination polymers, namely, 1D zigzag polymers [{TeFe3(CO)9Cu2}(L)]n (L=1,2-bis(4-pyridyl)ethane (bpea), 1; L=1,2-bis(4-pyridyl)ethylene (bpee), 5), 2D honeycomb-like polymers [{TeFe3(CO)9Cu}Cu(L)2.5]n (L=bpea, 2; L=bpee, 6), and 2D wave-like cation–anion polymer [{Cu2(L)4}({TeFe3(CO)9Cu}2(L))]n (L=1,3-bis(4-pyridyl)propane (bpp), 4), as well as the macrocycle [{TeFe3(CO)9Cu2}2(bpp)2] (3) have been quantitatively synthesized via the liquid-assisted grinding from the pre-designed cluster [TeFe3(CO)9Cu2(MeCN)2] with conjugated or conjugation-interrupted dipyridyl linkers. Notably, the most conjugation-interrupted bpp-bridged polymer 4 exhibited extraordinary semiconducting characteristics with an ultra-narrow bandgap of 1.43 eV and a DC conductivity of 1.5×10−2 Ω−1 cm−1, which violates our knowledge, mainly attributed to the through-space electron transport via non-classical C−H⋅⋅⋅O(carbonyl) hydrogen bonds and aromatic C−H⋅⋅⋅π interactions. The incorporated Te-Fe-CO anions can not only provide numerous possibilities for secondary interactions within these Cu-based polymers but also serve as a redox-active coordination ligand to promote their conductivities. The intriguing structure–property relationships were studied by X-ray and DFT analyses and further demonstrated by significant change in the oxidation state of Cu atoms by XPS and Cu K-edge XANES. Cross the bridge! A series of conjugation-interrupted dipyridyl-linked cluster-incorporated polymers have been synthesized by liquid-assisted grinding. These polymers exhibit surprising semiconducting characteristics with ultra-narrow bandgaps and high conductivities, which violates our knowledge, attributed to the through-space electron transport via non-classical C−H⋅⋅⋅O(carbonyl) hydrogen bonds and aromatic C−H⋅⋅⋅π interactions.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701257