Inorganic Chemistry, Vol.50, No.18, 9141-9146, 2011
Synthesis and Structure of a Bismuth(III)/Chromium(VI) Oxo Cluster Containing a Bi4Cr4O12 Core
Bismuth(III) compounds containing the Klauid's oxygen tripodal ligand [CpCo{P(O)(OEt)(2)}(3)](-) (L-OEt(-)) have been synthesized, and their interactions with dichromate in aqueous media were studied. The treatment of Bi5O(OH)(9)(NO3)(4) with NaLOEt in water afforded [LOEtBi(NO3)(2)](2) (1), whereas that of BiCl3 with NaLOEt in CH2Cl2 yielded LOEtBiCl2 (2). Chloride abstraction of 2 with AgX afforded [LOEtBiX2](2) [X- = triflate (OTf-) (3), tosylate (OTs-) (4)] In aqueous solutions at pH > 4, 4 underwent ligand redistribution to give the bis(tripod) complex [(L-OEt)(2)Bi(H2O)] [OTs] (5). The treatment of 4 with Na2Cr2O7 in acetone/water afforded the Bi(III)/Cr(VI) oxo cluster [(L-OEt)(4)Bi-4(mu(3)-CrO4)(2)(mu(3)-Cr2O7)(2)] (6) containing a unique Bi4Cr4O12 oxometallic core. Compound 6 oxidized benzyl alcohol to give ca. 6 equiv of benzaldehyde. The reaction between 2 and CrO3 yielded [LOEtBi(OCrO2Cl)](2)(mu-Cl)(2) (7). The crystal structures of complexes 4-7 have been determined.