Phosphine substituted hydrazones with or without nitro substituents were synthesized and characterized by multinuclear NMR, FT-IR, UV-Vis spectroscopy and single crystal X-ray diffraction. The anion recognition properties of phosphine oxides {Ph₂P(O)C₆H₄CHNNHPh} (2) and {Ph₂P(O)C₆H₄CHNNHC₆H₃ (2,4-NO₂) ₂} (4) with anions (F⁻, Cl⁻, Br⁻, I⁻, CH₃COO⁻ and H₂PO⁻ ₄ ) were investigated. The selectivity towards these anions is attributed to the hydrogen bonding capability of the NH bond. Competitive titrations have shown that the binding ability of fluoride with 4 is not influenced by the presence of other anions.

The synthesis of a Schiff base-appended macrocycle [{P(μ--^t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂] ₂(1) containing cyclodiphosphazane moieties is described. Reactions of 1 with H₂ O₂ and elemental selenium yielded derivatives tetrakis(oxide) [{P(O)(μ--^t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂] ₂ (2) and tetrakis(selenide)[{P(Se)(μ--^t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂] ₂ (3), in ∼80% yield. Tetragold complex [Au ₄Cl ₄ {{P(μ--^t BuN)} ₂ (O − m − C₆H₄ CHNCH₂) ₂ }₂] (4) was prepared by reacting 1 with [AuCl(SMe₂)] in 1:4 molar ratio. All the compounds have been characterized by various spectroscopic techniques. The molecular structure of 3 was confirmed by single crystal X-ray analysis.