Synthesis and properties of cobalt(II) coordination polymers linked by 4′-(4-pyridyl)-2,2′:6′,2-terpyridine

The cationic one-dimensional coordination polymers [{Co(pyterpy)(2)}{M(hfac)(2)}](2+) (M = Co(II) or Zn(II); pyterpy = 4'-(4-pyridyl)-2,2':6',2 ''-terpyridine; hfac = hexafluoroacetyloacetonate) feature alternating {Co(pyterpy)(2)} and {M(hfac)(2)} units linked through heteroditopic pyterpy ligands. Cocrystallization with [M(hfac)(3)](-) (M = Co(II) or Zn(II)) counteranions has afforded the compounds: [{Co(pyterpy)(2)}{Co(hfac)(2)}] [Co(hfac)(3)](2) (1) and [{Co(pyterpy)(2)}{Co0.7Zn0.3(hfac)(2)}][Zn(hfac)(3)](2) (2). Variable temperature crystallographic and magnetic studies indicate low spin cobalt(II) ions in the {Co(pyterpy)(2)} components of the coordination polymers up to room temperature; magnetic studies suggest the onset of a thermally induced spin crossover at these centers above room temperature. (C) 2018 Elsevier Ltd. All rights reserved.