Solvent-oriented structural diversity, sequential SCSC and low-temperature transformation in Cd-coordination polymers: unique turn-on-off sensing of Fe³⁺

Linker conformation engineering provides opportunities for the structural diversity of coordination polymers (CPs); however, the approaches for modulating the synthesis solvents to influence linker conformation are very limited, and they are facing unpredictable challenges to date. Herein, through strategies of solvent-oriented structural self-assembly and solvent-induced single-crystal to single-crystal transformation, eight structurally distinct Cd-CPs were controllably synthesized with the same linkers for the first time. The decisive role of solvents in the self-assembly and transformations in CPs has been demonstrated in depth. Besides, rare reversible CP-based phase transition phenomena at low temperatures were observed. One of these represents the first example of an unprecedented turn-on-off CP-based Fe3+ ion sensor.