The hydridotris(3-nitro-1,2,4-triazol-1-yl)borate, a new nitro-substituted electron withdrawing polydentate "scorpionate"-type ligand and related copper and silver phosphane complexes

The new tripodal “scorpionate”-type ligand, the sodium hydridotris(3-nitro-1,2,4-triazol-1-yl)borate Na[HB(tzNO2)3] (1), containing electron withdrawing nitro functional groups on the azolyl moiety, has been synthesized in high yield starting from 3-nitro-1,2,4-triazole and sodium borohydride. New copper(I) and silver(I) complexes, [HB(tzNO2)3]M(PR3)2 (M = Cu or Ag; PR3= P(C6H5)3, or P(p-C6H4CH3)3) have been synthesized from the reaction of CuCl or AgNO3 with Na[HB(tzNO2)3] and triphenylphosphane or tri(p-tolyl)phosphane, respectively. These compounds have been characterized by elemental analyses, FT-IR, ESI-MS and multinuclear NMR spectroscopy. X-ray crystal structure of Na[HB(tzNO2)3] (1) shows that it has polymeric network structure resulting from sodium atoms of tripodal Na[HB(tzNO2)3] forming inter-molecular Na-N bonds to three nitrogen atoms of three neighboring triazolyl moieties of Na[HB(tzNO2)3]. Each sodium center has distorted octahedral geometry with three short Na-N (inter-molecular) and three long Na-N bonds (to chelating N-atoms of [HB(tzNO2)3]- ligand). This nitro-substituted scorpionate ligand could be of interest due to its high coordinative flexibility from endo- to exo-polydentate coordination mode.