Sodium Salts of Substituted Tetracyanocyclopentadienides [C5(CN)4X]− (X= H, CN, NH2, NO2): Substituent Influence on the Crystal Structures of Potential Coordination Polymers.

Metathesis reactions of NaCl with the silver salts of substituted tetracyanocyclopentadienides [C-5(CN)(4)X](-) (X = H, CN, NO2, NH2) gives the corresponding sodium salts 1-4. While 1-3 give polymeric networks, held together by Pi-stacking as well as multiply bridging polydentate cyanocyclopentadienides and in part hydrogen bonda, the aminotetracyanocyclo-pentadienide 4 forms only a water-bridged dinuclear complexes, which are connected only by an intensive hydrogen bond network. Quite surprisingly, only the NO2-substituent in 3 coordinates to Na+ besides the cyano groups, while the NH2 group in 4 is only involved in hydrogen bonds.