Water-soluble (Pterin)rhenium(I) complex: Synthesis, structural characterization, and two reversible protonation-deprotonation behavior in aqueous solutions
A new water-soluble complex, Re(CO) 3(pterin)(H 2O), was synthesized and characterized by 1H NMR and FTIR spectroscopy, and by a combination of three mass spectrometry techniques: MALDI, probe electrospray ionisation (PESI), and ESI. Because, unlike most metal-pterin complexes, the Re I complex is q...
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2012
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_14341948_v_n30_p4801_Ragone http://hdl.handle.net/20.500.12110/paper_14341948_v_n30_p4801_Ragone |
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| Sumario: | A new water-soluble complex, Re(CO) 3(pterin)(H 2O), was synthesized and characterized by 1H NMR and FTIR spectroscopy, and by a combination of three mass spectrometry techniques: MALDI, probe electrospray ionisation (PESI), and ESI. Because, unlike most metal-pterin complexes, the Re I complex is quite soluble in water, appropriate single crystals could be obtained for structural X-ray analysis. We report here the first solid state molecular structure containing a pterin ligand coordinated to the Re(CO) 3 core. This determination revealed that strong H bonds between the hydrogen atom of the 2-amino group and crystallization water molecules give rise to a polymeric arrangement of Re(CO) 3(pterin) (H 2O) complexes in the lattice. Protonation studies in aqueous solutions of the Re I complex showed two acid-base equilibriums with pK a1 = 3.9 and pK a2 = 8.8. pK a1 was assigned to the protonation equilibrium at N3 of the pterin ligand in the complex and pK a2 could be ascribed to the deprotonation of a coordinated water molecule. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
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