AbstractPoly(cyclic) oxamates represent novel and potentially multidentate ligands for coordination chemistry. To obtain them, the treatment of 2-nitroaniline with two equivalents of oxalyl chloride afforded N,N′-bis(2-nitrophenyl)oxalamide (1), and by reduction of 1 with [NH4][CO2H] and Pd/C, N,N′-bis(2-aminophenyl)oxalamide (2, bapoxH6) was synthesized. After the addition of an equimolar amount of oxalyl chloride to a THF solution of 2 and aqueous work-up the 24-membered macrocycle H8L2 was obtained. In analogues experiments, the addition of ethoxalyl and oxalyl chloride to 2 afforded the 36-membered macrocycle H12L3. The addition of Cu(OAc)2·H2O and NaOH to 2 gave rise to the formation of [Cu2(bapoxH4)(OAc)2] (4). The identities of 1, 2 and H8L2 were determined by elemental analysis, IR, NMR spectroscopic studies and by mass spectrometry. The solid state structures of H8L2, H12L3 and 4 have been determined by single-crystal X-ray diffraction studies. Macrocycle H12L3 forms chains through intermolecular hydrogen bonds, while packing of 4 consists of layers held by intermolecular dispersion and hydrogen bond interactions. 24-mer H8L2 forms a cavity with a diameter of about 7.5 Å corresponding to an accessible volume of about 120 Å3 according to the well-established 55% solution and was found to bind bromide and iodide anions selectively.
Synthesis of Schiff Bases Compounds from Oxamic Hydrazide: Spectroscopic Characterization, X–ray Diffraction Structure and Antioxidant Activity Study
