Telltale diamagnetism at 50 K of a coordination polymer system

The synthesis of coordination polymers (e.g. Prussian blue) is as old modern chemistry itself, but never stops surprising people. We here report superconductivity observed a designer polymer system sporting the chemically soft mercaptan and hard carboxyl groups. mercapto-carboxyl (dubbed Mercarb, or QiuSuo in Mandarin Pinyin) synergy hints at Daoism carries over from molecular to solid state: sulfur donors bond with Co2+/Ni2+ (or other transition metal ions) afford 2D sheets for charge transport, while interlayer metal-carboxylate domain more ionic mediates into superconductive state.