| Abstract
| - Multinuclear NMR spectra were obtained forparamagnetic Mn(III) complexes. The binding of axial ligandsto Mn(III) was observable by NMR. Particularly interestingexamples are the 1H and 19F NMR spectra inCD3OD of the molecule illustrated here. The dataindicate that a hydrogen bond of the water molecule to the F atom ofthe PF6 counterion observed in the solid state (O-bound toMn(III)) is preserved inCD3OD.
- The 1H NMR spectra of symmetrically substitutedparamagnetic [(R,R‘-SALOPHEN)MnIII]+and [(R,R‘-SALOPHEN)MnIII]2(μ-O) complexes(SALOPHEN is 1,3-bis(salicylideneamino)benzene) wereobtained. All ofthe monomers and dimers yielded well-resolved but isotropically shifted1H NMR spectra. A diamagneticsuppression routine was applied to the 1H NMR spectra thatallowed observation of all rapidly relaxing resonances.The binding of axial ligands, acetate, methanol, water, andpyridine was also observable by 1H NMR.TwoX-ray crystal structures were obtained: [(3,3‘-17-crown-6-SALOPHEN)MnIII]·(CH3C(O)O)·BaTf2·2H2O,[9b]OAc·BaTf2·2H2O, crystallized inthe triclinic space group P1̄; with a =10.747(2) Å, b = 12.271(8) Å, c=16.206(6) Å, α = 106.10(4)°, β =103.07(2)°, γ = 106.06(3), and Z = 2,while[(3,3‘,6,6‘-(CH3)4-SALOPHEN)MnIII]PF6·H2O,[6b]PF6·H2O, crystallizedin the monoclinic space group P21/n,with a = 12.465(1) Å, b =13.366(2) Å, c = 15.240(1) Å, β = 103.051(7)°,and Z = 2.[9b]OAc·BaTf2·2H2Ohas the Mn(III) center ligated in theaxial positions by one oxygen of the acetate group and an oxygen fromone SO3CF3-. The secondoxygen of theacetate is bound to the Ba2+ residing in the crown ether.The water molecule in[6b]PF6·H2O is O-bound totheMn(III) center and also hydrogen bonded to one of the fluorineatoms of the PF6 counterion, O−F 3.01 Å.1Hand 19F NMR spectra revealed that the hydrogen bond in[6b]PF6·H2O was preservedin CD3OD.
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