Nucleophically transformed N-heterocyclic nitriles trapped by cyanooxomolybdates(IV) : crystallographic and spectroscopic study

The reaction of $K_{3}Na[Mo(CN)_{4}O_{2}]\cdot6H_{2}0$ with 2,3-dicyanopyrazine or 2-pyridinecarbonitrile in aqueous media results in isolation of two new compounds of formulae $(PPh_{4})_{2}[Mo(CN)_{3}O(pzac)]\cdot2H_{2}O$ (Hpzac = 3-carbamoyl-2-pyrazinecarboxylic acid) and $(PPh_{4})_{2}[Mo(CN)_{3}O(pynccn)]\cdot3H_{2}O\cdot EtOH$ (Hpynccn = 2- pyridineiminocarbonitrile) respectively. X-ray single crystal structure measurements as well as physico- chemicalmeasurements confirmtransformations of 2,3-dicyanopyrazine to3-carbamoyl-2-pyrazinecarb- oxylic acid and 2-pyridinecarbonitrile to 2-pyridineiminocarbonitrile. All complexes are characterized by elemental analysis, IR and UV-Vis spectroscopy. Metal-assisted ligand transformations are studied spec- trophotometrically in the pH range 8.5-11.5. Two different pathways of nitrile reactivity are shown and discussed.