Dynamic Nuclear Polarization of 1H, 13C, and 59Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)
نویسندگان
چکیده
The study of inorganic crystalline materials by solid-state NMR spectroscopy is often complicated by the low sensitivity of heavy nuclei. However, these materials often contain or can be prepared with paramagnetic dopants without significantly affecting the structure of the crystalline host. Dynamic nuclear polarization (DNP) is generally capable of enhancing NMR signals by transferring the magnetization of unpaired electrons to the nuclei. Therefore, the NMR sensitivity in these paramagnetically doped crystals might be increased by DNP. In this paper we demonstrate the possibility of efficient DNP transfer in polycrystalline samples of [Co(en)3Cl3]2·NaCl·6H2O (en = ethylenediamine, C2H8N2) doped with Cr(III) in varying concentrations between 0.1 and 3 mol %. We demonstrate that (1)H, (13)C, and (59)Co can be polarized by irradiation of Cr(III) with 140 GHz microwaves at a magnetic field of 5 T. We further explain our findings on the basis of electron paramagnetic resonance spectroscopy of the Cr(III) site and analysis of its temperature-dependent zero-field splitting, as well as the dependence of the DNP enhancement factor on the external magnetic field and microwave power. This first demonstration of DNP transfer from one paramagnetic metal ion to its diamagnetic host metal ion will pave the way for future applications of DNP in paramagnetically doped materials or metalloproteins.
منابع مشابه
Dynamic Nuclear Polarization of H, C, and Co in a Tris(ethylenediamine)cobalt(III) Crystalline Lattice Doped with Cr(III)
The study of inorganic crystalline materials by solid-state NMR spectroscopy is often complicated by the low sensitivity of heavy nuclei. However, these materials often contain or can be prepared with paramagnetic dopants without significantly affecting the structure of the crystalline host. Dynamic nuclear polarization (DNP) is generally capable of enhancing NMR signals by transferring the mag...
متن کاملPhotoreduction of Potassium Dichromate in Aqueous Solution using Cobalt doped ZnO Nanoparticles
Co-doped ZnO nanoparticles with different Cobalt contents were prepared by direct precipitation method. The materials were characterized by XRD, SEM and TEM techniques. The XRD results indicated that the particle size of pure ZnO and Co-doped ZnO is about 30-45nm. The toxic Cr(VI) in industrial wastewaters can be removed by a reduction from Cr(VI) to Cr(III). The reduction of Cr(VI) to Cr(III) ...
متن کاملDensity Functional Study of Cobalt-59 Nuclear Magnetic Resonance Chemical Shifts and Shielding Tensor Elements in Co(III) Complexes
A density functional method has been used to successfully predict the isotropic 59Co nuclear magnetic resonance (NMR) chemical shifts of the following anionic, cationic and neutral Co(III) complexes: [Co(CN)6], [Co(NH3)6], [Co(NO2)6], [Co(NH3)4CO3], Co(acac)3, and [Co(en)3]. Isotropic chemical shifts are wellreproduced by using Wachters’ cobalt basis set and uniform 6-31G* basis sets on the lig...
متن کامل59Co NMR Studies of Diamagnetic Porphyrin Complexes in the Solid Phase
Solid state 59Co nuclear magnetic resonance (NMR) spectra were recorded on diamagnetic complexes with general structure Co(Por)L2, where Por ) tetraphenylporphyrin, tetramethoxyphenylporphyrin, and octaethylporphyrin; and L ) imidazole, methylimidazole, pyridine, and isoquinoline. Measurements were carried out at different magnetic field strengths (4.7, 7.1, and 11.7 T) on both static and spinn...
متن کاملSynthesis, Characterization and X-Ray Crystal Structure of a Cobalt(III) Complex with 2-Bis(pyridine-2-carboxamido)-4,5-dimethylbenzene Ligand
An octahedral cobalt(III) complex, trans-[(Me2bpb)Co(bzlan)2]ClO4 (1), with H2Me2bpb = N,N’-(4,5-dimethyl-1,2-phenylene)dipicolinamide and bzlan = benzylamine, has been synthesized and characterized by elemental analyses, IR, UV-Vis, and 1H NMR spectroscopy. The structure of this complex has been determined by X-ray crystallography. The Me2bpb2– is a di-anionic tetradentate ligand furnishing a ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 136 شماره
صفحات -
تاریخ انتشار 2014