A One-Dimensional π-d Conjugated Coordination Polymer for Sodium Storage with Catalytic Activity in Negishi Coupling

π-d Conjugated coordination polymers (CCPs) have attracted much attention for various applications, although the chemical states and structures of many CCPs are still blurry. Now, a one-dimensional (1D) π-d conjugated coordination polymer for high performance sodium-ion batteries is presented. The chemical states of the obtained coordination polymer are clearly revealed. The electrochemical process undergoes a three-electron reaction and the structure transforms from C=N double bonds and Ni^II to C-N single bonds and Ni^I , respectively. Our unintentional experiments provided visual confirmation of Ni^I . The existence of Ni^I was further corroborated by its X-ray absorption near-edge structure (XANES) and its catalytic activity in Negishi cross-coupling.