NMR Study of Partition and Permeation Properties of Ga(III) Chelates

Abstract

We found that tris(3-hydroxy-4-pyridinonate) Fe(III) complex [Fe(mpp)3] appears to be a strong candidate for iron fertilizer [1]. Further studies in which three Fe-chelates of the same family of ligands were compared tris(3-hydroxy-4-pyridinonate) Fe(III) complexes [Fe(mpp)3, Fe(dmpp)3 and Fe(etpp)3], were indicative that the first chelate presents a superior ability to be translocated from the roots to the shoots. The three complexes exhibit variable lipophilicity and for that reason will interact differently with membranes. To get insight on the permeation properties of Fe(III)-chelates, we performed NMR studies with parent diamagnetic/isostructural Ga(III)-chelates. The affinity of the complexes for the phospholipid bilayer of POPC/POPE liposomes and permeation properties of the Ga-chelates were estimated on the basis of the induced alterations of a number of NMR parameters, such as chemical shifts, line shape, spin-lattice relaxation time (T1), and translational diffusion coefficient of the lipids and the liposomes. Acknowledgements: This work received financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020, through the projects UID/QUI/50006/2013-POCI/01/0145/FEDER/007265 (LAQV/REQUIMTE) and project PTDC/AGRPRO/3515/2014-POCI-01-0145-FEDER-016599. [1] Santos, C.S., Carvalho, S.M.P., Leite, A., Moniz, T., Roriz, M., Rangel, A.O.S.S., Rangel, M., Vasconcelos, M.W., Plant Physiology and Biochemistry, 2016, 106, 91-100.