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Investigation of Two Zr-p-NO2Bn-DOTA Isomers via NMR and Quantum Chemical Studies |
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| Authors: | Dr Yong Sok Lee Dr Robert D O'Connor Dr Olga Vasalatiy |
| Institution: | 1. Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA;2. Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 USA;3. Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD 20850 USA |
| Abstract: | A combination of NMR studies and quantum chemical calculations were employed to investigate the structure and energetics of Zr4+ chelates of pNO2Bn-DOTA. We have demonstrated that two discrete regioisomeric chelates are generated during the complex formation. The nitrobenzyl substituent can adopt either an equatorial corner or side position on the macrocyclic ring. These regioisomers are incapable of interconversion and were isolated by HPLC. The corner isomer is more stable than the side, and the SAP conformer of both regioisomers is energetically more favorable than the corresponding TSAP conformer. |
| Keywords: | Corner and side regioisomers SAP and TSAP isomers Macrocyclic ligands Structure elucidation Zirconium |