TY - JOUR
T1 - Antimony-substituted Keggin-type polyoxomolybdates
T2 - Polar crystals and catalytic oxidative dehydrogenation of alcohols
AU - Khenkin, Alexander M.
AU - Shimon, Linda J.W.
AU - Neumann, Ronny
PY - 2001
Y1 - 2001
N2 - An antimony-substituted polyoxomolybdate, [PSbIII(H2O) -Mo11O39]4-, of the α-Keggin structure, has been synthesized. Although the molecular structure is typical, we have found from the analysis of the X-ray diffraction data that the crystal is anisotropic with alignment of the molecular units so that the substituted antimony atoms are all directed along the polar c axis and on the same side of the molecular unit. UV/Vis, ESR and magnetic susceptibility data support a formulation of [PSbIII(H2O)Mo11O39]4- whereby there is partial electron delocalization with some formation (10-20%) of MoV. Oxidation of [PSbIII(H2O)Mo11O39]4- with ozone or bromine yields the oxidized species [PSbV(O)Mo11O39]4- and [PSbV(Br)Mo11O39]3-. In the anaerobic oxydehydrogenation of alcohols, [PSbV(O)Mo11O39]4- is more active than [PSbV(Br)Mo11O39]3-. Catalytic aerobic oxidation of benzylic alcohols to aldehydes was also possible with no over-oxidation and formation of carboxylic̈ acids.
AB - An antimony-substituted polyoxomolybdate, [PSbIII(H2O) -Mo11O39]4-, of the α-Keggin structure, has been synthesized. Although the molecular structure is typical, we have found from the analysis of the X-ray diffraction data that the crystal is anisotropic with alignment of the molecular units so that the substituted antimony atoms are all directed along the polar c axis and on the same side of the molecular unit. UV/Vis, ESR and magnetic susceptibility data support a formulation of [PSbIII(H2O)Mo11O39]4- whereby there is partial electron delocalization with some formation (10-20%) of MoV. Oxidation of [PSbIII(H2O)Mo11O39]4- with ozone or bromine yields the oxidized species [PSbV(O)Mo11O39]4- and [PSbV(Br)Mo11O39]3-. In the anaerobic oxydehydrogenation of alcohols, [PSbV(O)Mo11O39]4- is more active than [PSbV(Br)Mo11O39]3-. Catalytic aerobic oxidation of benzylic alcohols to aldehydes was also possible with no over-oxidation and formation of carboxylic̈ acids.
KW - Alcohols
KW - Antimony
KW - Dehydrogenations
KW - Molybdenum
KW - Polyoxometalates
UR - http://www.scopus.com/inward/record.url?scp=0035119226&partnerID=8YFLogxK
U2 - 10.1002/1099-0682(200103)2001:3<789::aid-ejic789>3.0.co;2-w
DO - 10.1002/1099-0682(200103)2001:3<789::aid-ejic789>3.0.co;2-w
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AN - SCOPUS:0035119226
SN - 1434-1948
SP - 789
EP - 794
JO - European Journal of Inorganic Chemistry
JF - European Journal of Inorganic Chemistry
IS - 3
ER -