TY - JOUR
T1 - Polyoxomolybdodiphosphonates
T2 - Examples incorporating ethylidenepyridines
AU - Banerjee, Abhishek
AU - Raad, Farah S.
AU - Vankova, Nina
AU - Bassil, Bassem S.
AU - Heine, Thomas
AU - Kortz, Ulrich
PY - 2011/11/21
Y1 - 2011/11/21
N2 - We have synthesized and structurally characterized three pyridylethylidene-functionalized diphosphonate-containing polyoxomolybdates, [{MoVIO3}2{MoV2O 4}{HO3PC(O)(CH2-3-C5NH 4)PO3}2]6- (1), [{Mo VI2O6}2{MoV 2O4}{O3PC(O)(CH2-3-C 5NH4)PO3}2]8- (2), and [{MoV2O4(H2O)}4{O 3PC(O)(CH2-3-C5NH4)PO 3}4]12- (3). Polyanions 1-3 were prepared in a one-pot reaction of the dinuclear, dicationic {MoV2O 4(H2O)6}2+ with 1-hydroxo-2-(3- pyridyl)ethylidenediphosphonate (Risedronic acid) in aqueous solution. Polyanions 1 and 2 are mixed-valent MoVI/V species with open tetranuclear and hexanuclear structures, respectively, containing two diphosphonate groups. Polyanion 3 is a cyclic octanuclear structure based on four {MoV2O4(H2O)} units and four diphosphonates. Polyanions 1 and 2 crystallized as guanidinium salts [C(NH 2)3]5H[{MoVIO3} 2{MoV2O4}{HO3PC(O) (CH2-3-C5NH4)PO3} 2]•13H2O (1a) and [C(NH2) 3]6H2[{MoVI2O 6}2{MoV2O4}{O 3PC(O)(CH2-3-C5NH4)PO 3}2]•10H2O (2a), whereas polyanion 3 crystallized as a mixed sodium-guanidinium salt, Na8[C(NH 2)3]4[{MoV2O 4(H2O)}4{O3PC(O)(CH 2-3-C5NH4)PO3}4] •8H2O (3a). The compounds were characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric and elemental analyses. The formation of polyanions 1 and 3 is very sensitive to the pH value of the reaction solution, with exclusive formation of 1 above pH 7.4 and 3 below pH 6.6. Detailed solution studies by multinuclear NMR spectrometry were performed to study the equilibrium between these two compounds. Polyanion 2 was insoluble in all common solvents. Detailed computational studies on the solution phases of 1 and 3 indicated the stability of these polyanions in solution, in complete agreement with the experimental findings.
AB - We have synthesized and structurally characterized three pyridylethylidene-functionalized diphosphonate-containing polyoxomolybdates, [{MoVIO3}2{MoV2O 4}{HO3PC(O)(CH2-3-C5NH 4)PO3}2]6- (1), [{Mo VI2O6}2{MoV 2O4}{O3PC(O)(CH2-3-C 5NH4)PO3}2]8- (2), and [{MoV2O4(H2O)}4{O 3PC(O)(CH2-3-C5NH4)PO 3}4]12- (3). Polyanions 1-3 were prepared in a one-pot reaction of the dinuclear, dicationic {MoV2O 4(H2O)6}2+ with 1-hydroxo-2-(3- pyridyl)ethylidenediphosphonate (Risedronic acid) in aqueous solution. Polyanions 1 and 2 are mixed-valent MoVI/V species with open tetranuclear and hexanuclear structures, respectively, containing two diphosphonate groups. Polyanion 3 is a cyclic octanuclear structure based on four {MoV2O4(H2O)} units and four diphosphonates. Polyanions 1 and 2 crystallized as guanidinium salts [C(NH 2)3]5H[{MoVIO3} 2{MoV2O4}{HO3PC(O) (CH2-3-C5NH4)PO3} 2]•13H2O (1a) and [C(NH2) 3]6H2[{MoVI2O 6}2{MoV2O4}{O 3PC(O)(CH2-3-C5NH4)PO 3}2]•10H2O (2a), whereas polyanion 3 crystallized as a mixed sodium-guanidinium salt, Na8[C(NH 2)3]4[{MoV2O 4(H2O)}4{O3PC(O)(CH 2-3-C5NH4)PO3}4] •8H2O (3a). The compounds were characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric and elemental analyses. The formation of polyanions 1 and 3 is very sensitive to the pH value of the reaction solution, with exclusive formation of 1 above pH 7.4 and 3 below pH 6.6. Detailed solution studies by multinuclear NMR spectrometry were performed to study the equilibrium between these two compounds. Polyanion 2 was insoluble in all common solvents. Detailed computational studies on the solution phases of 1 and 3 indicated the stability of these polyanions in solution, in complete agreement with the experimental findings.
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U2 - 10.1021/ic201652h
DO - 10.1021/ic201652h
M3 - Article
C2 - 22004183
AN - SCOPUS:81255142571
SN - 0020-1669
VL - 50
SP - 11667
EP - 11675
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 22
ER -