Chemistry, like all the natural sciences, Recommanded Product: 5813-64-9, begins with the direct observation of nature¡ª in this case, of matter.5813-64-9, Name is 2,2-Dimethylpropan-1-amine, SMILES is CC(C)(C)CN, belongs to amides-buliding-blocks compound. In a document, author is Shaik, Baji Vali, introduce the new discover.
Toward inert paramagnetic Ni(II)-based chemical exchange saturation transfer MRI agents
The Ni2+ complexes with hexadentate ligands containing two 6-methylpicolinamide groups linked by ethane-1,2-diamine (dedpam) or cyclohexane-1,2-diamine (chxdedpam) spacers were investigated as potential contrast agents in magnetic resonance imaging (MRI). The properties of the complexes were compared to that of the analogues containing 6-methylpicolinate units (dedpa(2-) and chxdedpa(2-)). The X-ray structure of the [Ni(dedpam)](2+) complex reveals a six-coordinated metal ion with a distorted octahedral environment. The protonation constants of the dedpa(2-) and dedpam ligands and the stability constants of their Ni2+ complexes were determined using pH-potentiometry and spectrophotometric titrations (25 degrees C, 0.15 M NaCl). The [Ni(dedpa)] complex (log K-NiL = 20.88(1)) was found to be considerably more stable than the corresponding amide derivative [Ni(dedpam)](2+) (log K-NiL = 14.29(2)). However, the amide derivative [Ni(chxdedpam)](2+) was found to be considerably more inert with respect to proton-assisted dissociation than the carboxylate derivative [Ni(chxdedpa)]. A detailed H-1 NMR and DFT study was conducted to assign the H-1 NMR spectra of the [Ni(chxdedpa)] and [Ni(chxdedpam)](2+) complexes. The observed H-1 NMR paramagnetic shifts were found to be dominated by the Fermi contact contribution. The amide resonances of [Ni(chxdedpam)](2+) at 91.5 and 22.2 ppm were found to provide a sizeable chemical exchange saturation transfer effect, paving the way for the development of NiCEST agents based on these rigid non-macrocyclic platforms.
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