O,O′-Diester Methylenediphosphonotetrathioate: Synthesis, Characterization, and Potential Applications

Abstract

A new transformation of methylene-bis(phosphonic dichloride) into tetrathiobisphosphonate derivatives is reported. The reaction of methylene-bis(phosphonic dichloride) with 1,2-ethanedithiol in bromoform in the presence of AlCl3 formed methylene-bis(1,3,2-dithiaphospholane-2-sulfide), which gave rise to O,O′-diester-methylenediphosphonotetrathioate analogues 1a–k upon reaction with phenols and alkyl alcohols in the presence of DBU. Reaction mechanisms are proposed, and all products were characterized by 31P, 13C, and 1H NMR. An X-ray crystal structure was obtained for intermediate 2. The potential of the novel scaffold for selective coordination of metal-ions was examined by coordination of Hg(II) and Pb(II) by 1f, as determined by FT-IR, and chelation of Zn(II), but not Ca(II), by 1b, as determined by 31P/1H NMR. UV–vis measurements of 1g–Ni(II) mixture revealed a 2:1 ligand:metal complex. These derivatives are potential antioxidants, and their ability to inhibit ·OH formation in Fenton reactions was quantified by ESR measurements. Analogue 1g proved to be a most potent antioxidant (IC50 53 μM), inhibiting the Cu(I)-catalyzed Fenton reaction at lower concentrations than GSH, ascorbic acid, and EDTA. Analogue 1c inhibited the Fe(II)-catalyzed Fenton reaction at about the same concentrations as ascorbic acid (IC50 83 vs 93 μM). In summary, the novel compounds, 1a–k, proved to chelate various borderline/soft Lewis acid metal-ions, and may be useful as antioxidants and metal extractors.

Novel Cu(I)-Selective Chelators Based on a Bis(phosphorothioyl)amide Scaffold

“…7 A gauche conformation was observed between the two dithiaphospholane rings. The average PS and P−C bond lengths were 2.044 and 1.827 Å, respectively, longer than PS and P−N bonds in 6−8 due to the lack of electron delocalization in 14.…”

“…Analogue 1, R = CH 3 (CH 2 ) 7 , inhibited the Fe(II)-catalyzed Fenton reaction at about the same concentration as ascorbic acid (IC 50 83 vs 93 μM). 7 The related metal-ion chelators, bis(dialkyl/arylphosphorothioyl)amide (BPA) analogues, 3a (Figure 2), allow delocalization of electrons and therefore are expected to be more polarizable than the corresponding bisphosphonate analogues. 9 BPA derivatives are soft/borderline metal ligands that bind a variety of metal ions (e.g., Zn(II), 10 Ni(II), 11,12 Cu(I)/(II), 13,14 and Mn(II) 15,16 ).…”

Fire Self-Extinguishing Cotton Fabric: Development of Piperazine Derivatives Containing Phosphorous-Sulfur-Nitrogen and Their Flame Retardant and Thermal Behaviors

“…When thoroughly examined, the two spectra reveal their differences by their signature peaks. The spectroscopic feature at 722 cm −1 is found for 3-TMPT, which corresponds to the stretching band of P=S [20] [21]. At 2980 cm −1 , CH stretch in aliphatic chain of O-C-C group of 7-TEPP appears as a small sharp peak [20].…”

“…In addition to signature peaks of MeOH, 3-TMPT 3D spectrum exhibits three new types of peaks at 1263 and 1178 cm −1 (SO 2 ) [34] [35], 931 cm −1 (P-N) and 824 and 723 cm −1 (P=S) [20] [21]. Overall, the intensity of most peaks in 3-TMPT is superior to that of 7-TEPP peaks in contrast with the lower concentration of TMPT on the fabric.…”

Novel crown-ether–methylenediphosphonotetrathioate hybrids as Zn(ii) chelators

“…Therefore, we recently developed methylenediphosphonotetrathioate (MDPT), 17 2, its O,O′-diester-MDPT derivatives, 18 3, and nucleoside-5′-MDPT analogues 4 and 5 (Fig. 1), as selective Zn(II) chelators.…”