Reversible Pressure‐Controlled Depolymerization of a Copper(II)‐Containing Coordination Polymer

• Published in: Chemistry : a European journal 2017-09, Vol.23 (51), p.12480-12483
• Main Authors: Clegg, Jack K., Brock, Aidan J., Jolliffe, Katrina A., Lindoy, Leonard F., Parsons, Simon, Tasker, Peter A., White, Fraser J.
• Format: Article
• Language: English
• Subjects: Chemistry; coordination polymer; Coordination polymers; Copper; Copper compounds; Depolymerization; Diamonds; Diffraction; high-pressure chemistry; Phase change; Phase transitions; Polymers; Pressure; Single crystals; stimuli responsive; X-ray diffraction; X-ray structure
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201703115

A unique pressure‐induced Cu−N bond breaking/bond forming reaction is reported. The variation of pressure on a single crystal of a one‐dimensional copper‐ (II)‐containing coordination polymer (Cu2L2(1‐methylpiperazine)2]n, where H2L is 1,1′‐(1,3‐phenylene)‐bis(4,4‐dimethylpentane‐1,3‐dione)), was monitored using single crystal X‐ray diffraction with the aid of a diamond anvil cell. At a very low elevated pressure (≈0.05 GPa) a remarkable reversible phase change was observed. The phase change results in the depolymerization of the material through the cleavage and formation of axial Cu−N bonds as well as “ring flips” of individual axially coordinated 1‐methylpiperazine ligands. Overall, the pressure‐induced phase change is associated with a surprising (and non‐intuitive) shift in structure‐from a 1‐dimensional coordination polymer to a discrete dinuclear complex. Under pressure: The application of elevated pressure to single crystals of a copper(II)‐containing coordination polymer induces a reversible depolymerization reaction and single‐crystal single‐crystal transformation.