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Tripodal aminophenolate ligand complexes of aluminum(III), gallium(III), and indium(III) in water

TitleTripodal aminophenolate ligand complexes of aluminum(III), gallium(III), and indium(III) in water
Publication TypeJournal Article
Year of Publication1997
AuthorsCaravan, P, Orvig, C
JournalInorganic Chemistry
Volume36
Pagination236-248
Date PublishedJan
Type of ArticleArticle
ISBN Number0020-1669
KeywordsACID, BINDING, EQUILIBRIUM-CONSTANTS, GA(III), HUMAN-SERUM TRANSFERRIN, IN(III), IN-VIVO, METAL-IONS, SCHIFF-BASE LIGANDS, STABILITIES
Abstract

Four water-soluble amine phenols have been prepared: tris(((2-hydroxy-5-sulfobenzyl)amino)ethyl)amine (H(6)TRNS), 1,1,1-tris(((2-hydroxy-5-sulfobenzyl)amino)methyl)ethane (H(6)TAMS), 1,2,3-tris((2-hydroxy-5-sulfobenzyl)amino)propane (H(6)TAPS), and cis,cis-1,3,5-tris((2-hydroxy-5-sulfobenzyl)amino)cyclohexane (H(6)TACS). Complex formation constants have been measured at 25 degrees C (mu = 0.16 M NaCl): log K [M(TRNS)](3-) ([M(HTRNS)](2-)) M = Ga 28.55 (36.90), In 29.3 (34.9); log K [M(TAMS)](3-) ([M(HTAMS)](2-)) M = Al 22.5 (29.3), Ga 31.53, In 28.49; log K [M(TAPS)](3-) ([M(HTAPS)](2-)) M = Al 22.8 (29.0), Ga 31.54 (35.15), In 27.56 (31.93). The order of stability is Ga(III) > In(III) > Al(III) for H(6)TAMS and H(6)TAPS, while far H(6)TRNS it is Ga(III) approximate to In(lII) > Al(III). The solution structures of the complexes have been probed by multinuclear NMR (H-1, C-13, Al-27, Ga-71, In-115) and UV spectroscopic studies, and these solution structures are compared with solid state structures for analogous complexes. The H-1 NMR spectrum in D2O establishes TAPS to be preorganized for metal ion binding. H(6)TACS exists in the wrong conformation for metal ion binding, and this results in slow complexation kinetics and relatively weaker binding.

URL<Go to ISI>://A1997WC88700021