Mixed-ligand CoII and CdII complexes with 4-aminoantipyrine

Self-assembly of 4-aminoantipyrine (AAP) and 5-nitroisophthalic acid (H2NIP) with Co(CH3COO)(2) or Cd(NO3)(2) in CH3OH-H2O at room temperature generated {[Co-2(AAP)(NIP)(H2O)(8)][Co(AAP)(NIP)(2)(H2O)(2)](H2O)(4.5)} (1) and {[Cd(AAP)(NIP)(H2O)](H2O)}(n) (2), which were further characterized by X-ray diffraction, IR spectra, elemental analysis and solid-state fluorescence spectra. The structure analysis indicates that 1 contains two individual fragments, one NIP-bridged six-coordinate binuclear Co-II cation and a mononuclear Co-II dianion. The binuclear units are connected into 1-D chains via O-H center dot center dot center dot O hydrogen bond interactions, which were further assembled into a 2-D supramolecular layer bridged by the mononuclear Co-II unit. Complex 2 is a linear NIP bridged seven-coordinate Cd-II polymeric chain with the terminal AAP ligands as decorations, and are further extended into 2-D network by classic hydrogen bonds and stacking interactions. Both solid complexes exhibit emission spectra from intraligand electron transfer at room temperature.