Crystal synthesis of 1,4-phenylenediamine salts and coordination networksElectronic supplementary information (ESI) available: Details of the structure of 2solved from XRPD data and details of the crude structure solution of 4. See DOI: 10.1039/c0ce00020e

para-Phenylenediamine (ppda) may be ground together with metal chloride salts MCl2to produce the coordination network compounds [{(ppda)MCl2}n] {M = Zn (2), Cd (4), Cu (6)}. Its dihydrochloride salt [H2ppda]Cl2can be ground with MCl2to produce the layered salt structures [H2ppda][MCl4] {M = Zn (1), Cd (3), Cu (5)}, which (when M = Zn or Cd) may then be converted into 2or 4respectively by grinding with solid KOH. Alternatively, [H2ppda][MCl4] will react directly with appropriate basic metal compounds (hydroxides and/or carbonates) to give 2or 4, which can then be converted back to the salts by reaction with gaseous HCl. The interconversion of 5and 6is more complicated, with different combinations of starting material giving different products. The crystal structure of 2has been solved ab initiofrom the powder-diffraction data, and is shown to consist of zigzag polymeric chains containing alternating ppda and MCl2units. [ABSTRACT FROM AUTHOR]