Tunable structures aroused by cation exchange reaction of solvent-mediated mechanism

In our efforts to tune structure by cation exchange reaction, a rare 1-D meso-helical chain [CdL(Ac)2]n (1) was immersed into the methanol solution of Hg(Ac)2, and then new crystals of {[HgL0.5(Ac)2]·(CH3OH)}n (2) (L = 1,4-bis(2-methylbenzimidazol-1-ylmethyl) benzene) were obtained on the surface of 1. Single crystal X-ray analysis reveals that complex 2 shows a 1-D zigzag chain, in which the mercury ion adopts an unprecedented six-coordinated mode in binuclear unit. Notably, the framework of 2 is completely different from that of 1. In addition, the determination of Scanning Electron Microscope and Energy-Dispersive X-ray Spectrometry reveals that the exchange is a recurrent dissolving-exchange-crystallization process of solvent-mediated mechanism. This work provides a new effective tactic of adjusting molecular structures.