“…Proposed Mechanism of Complexation with MO-86 and Structures of the Complexes. Previous reports have shown that complexation of molecules similar to phosphonate esters ( 3 , 5 , 7 , and 9 ) and phosphonic acids ( 4a , b ) by MO-86 involves coordination of Fe(III) with the oxygen atoms attached to phosphorus. , Spectroscopic measurements suggest that complexation in a 3:1 phosphonate ester/Fe(III) mixture involves a change in the coordination number of phosphorus from 5 to 4 and formation of three four-membered rings consisting of P−O−Fe−O bonds . However, magnetic measurements on and solubility characteristics of these complexes are more consistent with eight-membered phosphonate bridges and four-membered chelate rings, depending on the reaction temperature (Figure ). , The complexes between 2 , 4 , or 6a and MO-86 did not gelate any of the liquids that were gelated by the corresponding MO-86 complexes with a mono-ester ( 3 , 5 , 7a , or 9 ).…”
Section: Resultsmentioning
confidence: 98%
“…Thus, it is reasonable to assume that complexation of 3 , 5 , 7a , and 9 by MO-86 involves interaction of ferric ion with the unesterified oxygen atoms. 5 Two possible arrangements of the Fe(III) complex between phosphonate esters and the Fe(III) ions of MO-86. 36a, …”
Section: Resultsmentioning
confidence: 99%
“…Two possible arrangements of the Fe(III) complex between phosphonate esters and the Fe(III) ions of MO-86. 36a, …”
The properties of thermally reversible organogels in which the gelators consist of a phosphonic acid monoester, phosphonic acid, or phosphoric acid monoester and a ferric salt are probed by IR and NMR spectroscopies, optical microscopy, X-ray diffraction, rheology, and light and small-angle neutron scattering (SANS) techniques. This is one of a small number of two-component molecular gelator systems in which gelation can be induced isothermally. The data indicate that complexation between the phosphonate moieties and Fe(III) is accompanied by their in situ polymerization to form self-assembled fibrillar networks that encapsulate and immobilize macroscopically the organic liquid component. From SANS measurements, the cross-sectional radii of the cyclindrical fibers are ca. 15 A. The efficiencies of the gelators (based on the diversity of the liquids gelated, the minimum concentration of gelator required to make a gel at room temperature, and the temporal and thermal stabilities of the gels) have been determined. With a common ferric salt and liquid component, phosphonic acid monoesters are generally more efficient than phosphinic acids or phosphoric acid esters. Of the phosphonic acid monoesters, monophosphonates are better gelator components than bisphosphonates, and introduction of an omega-hydroxy group on the alkyl chain directly attached to phosphorus reduces significantly gelation ability. Several of the gels are stable for very long periods at room temperature. When heated, they revert to sols over wide temperature ranges. The structures of the gelator complexes and the mechanism of their formation and transformation to gels in selected liquids are examined as well.
“…Proposed Mechanism of Complexation with MO-86 and Structures of the Complexes. Previous reports have shown that complexation of molecules similar to phosphonate esters ( 3 , 5 , 7 , and 9 ) and phosphonic acids ( 4a , b ) by MO-86 involves coordination of Fe(III) with the oxygen atoms attached to phosphorus. , Spectroscopic measurements suggest that complexation in a 3:1 phosphonate ester/Fe(III) mixture involves a change in the coordination number of phosphorus from 5 to 4 and formation of three four-membered rings consisting of P−O−Fe−O bonds . However, magnetic measurements on and solubility characteristics of these complexes are more consistent with eight-membered phosphonate bridges and four-membered chelate rings, depending on the reaction temperature (Figure ). , The complexes between 2 , 4 , or 6a and MO-86 did not gelate any of the liquids that were gelated by the corresponding MO-86 complexes with a mono-ester ( 3 , 5 , 7a , or 9 ).…”
Section: Resultsmentioning
confidence: 98%
“…Thus, it is reasonable to assume that complexation of 3 , 5 , 7a , and 9 by MO-86 involves interaction of ferric ion with the unesterified oxygen atoms. 5 Two possible arrangements of the Fe(III) complex between phosphonate esters and the Fe(III) ions of MO-86. 36a, …”
Section: Resultsmentioning
confidence: 99%
“…Two possible arrangements of the Fe(III) complex between phosphonate esters and the Fe(III) ions of MO-86. 36a, …”
The properties of thermally reversible organogels in which the gelators consist of a phosphonic acid monoester, phosphonic acid, or phosphoric acid monoester and a ferric salt are probed by IR and NMR spectroscopies, optical microscopy, X-ray diffraction, rheology, and light and small-angle neutron scattering (SANS) techniques. This is one of a small number of two-component molecular gelator systems in which gelation can be induced isothermally. The data indicate that complexation between the phosphonate moieties and Fe(III) is accompanied by their in situ polymerization to form self-assembled fibrillar networks that encapsulate and immobilize macroscopically the organic liquid component. From SANS measurements, the cross-sectional radii of the cyclindrical fibers are ca. 15 A. The efficiencies of the gelators (based on the diversity of the liquids gelated, the minimum concentration of gelator required to make a gel at room temperature, and the temporal and thermal stabilities of the gels) have been determined. With a common ferric salt and liquid component, phosphonic acid monoesters are generally more efficient than phosphinic acids or phosphoric acid esters. Of the phosphonic acid monoesters, monophosphonates are better gelator components than bisphosphonates, and introduction of an omega-hydroxy group on the alkyl chain directly attached to phosphorus reduces significantly gelation ability. Several of the gels are stable for very long periods at room temperature. When heated, they revert to sols over wide temperature ranges. The structures of the gelator complexes and the mechanism of their formation and transformation to gels in selected liquids are examined as well.
Metal(II) halides react ‐with diisopropyl methylphosphonate (DIMP) at 150–220°C with formation of the following complexes: M[(C3H7O)CH3POO]2 (M = Fe, VO); M2[(C3H7O)CH3POO]2[OOP(CH3)–O–P(CH3)OO], (M = Ca, Mn, Co Ni); Zn[OOP(CH3)–O–P(CH3)OO]; Cu[CH3POO(OH)]3 (from CuCl2 · 2 H2O + DIMP); Cu[CH3PO3] (from CuX2 + DIMP; X = Cl, Br). These complexes were characterized by means of their electronic and infrared spectra and magnetic susceptibilities.
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