Coexistence of Cu(ii) and Cu(i) in Cu ion-doped zeolitic imidazolate frameworks (ZIF-8) for the dehydrogenative coupling of silanes with alcohols

Yan Dai; Peng Xing; Xiaoqin Cui; Zhihong Li; Xianming Zhang

doi:10.1039/c9dt03181b

Coexistence of Cu(ii) and Cu(i) in Cu ion-doped zeolitic imidazolate frameworks (ZIF-8) for the dehydrogenative coupling of silanes with alcohols

Dalton Trans. 2019 Nov 28;48(44):16562-16568. doi: 10.1039/c9dt03181b. Epub 2019 Oct 28.

Authors

Yan Dai¹, Peng Xing², Xiaoqin Cui², Zhihong Li², Xianming Zhang³

Affiliations

¹ Institute of Crystalline Materials, Shanxi University, 030006, Taiyuan, China. xmzhang@sxu.edu.cn ydai@sxu.edu.cn and State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, 361005, Xiamen, China.
² Institute of Crystalline Materials, Shanxi University, 030006, Taiyuan, China. xmzhang@sxu.edu.cn ydai@sxu.edu.cn and Institute of Molecular Science, Shanxi University, 030006, Taiyuan, China.
³ Institute of Crystalline Materials, Shanxi University, 030006, Taiyuan, China. xmzhang@sxu.edu.cn ydai@sxu.edu.cn and School of Chemistry and Material Science, Shanxi Normal University, 041004, Linfen, China.

PMID: 31657403
DOI: 10.1039/c9dt03181b

Abstract

Recently, metal-ion-doped zeolitic imidazolate frameworks have gained considerable attention for their structure tailorability and potential catalytic applications. Herein, Cu ion-doped ZIF-8 nanocrystals were successfully prepared by the mechanical grinding of Cu(NO₃)₂, ZnO and 2-methylimidazole (HMeIM) using ethanol as an additive. In contrast to the general view that only Cu(ii) is present in Cu-doped ZIF-8, we found the coexistence of Cu(ii) and Cu(i) in this material, which was supported by XPS and X-ray induced Auger electron spectroscopy (XAES) characterizations. Moreover, ethanol might have acted as a reducer to induce the reduction of Cu(ii) during synthesis. Due to the mixed valency of Cu ions, the Cu ion-doped ZIF-8 nanocrystals showed excellent catalytic performance in the dehydrogenative coupling of silanes with alcohols.