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2258695 
Journal Article 
Copper(II) 15-metallacrown-5 lanthanide(III) complexes derived from L-serine and L-threonine hydroxamic acids 
Pacco, A; Absillis, G; Binnemans, K; Parac-Vogt, TN 
2008 
Yes 
Journal of Alloys and Compounds
ISSN: 0925-8388 
451 
1-2 
38-41 
WOS:000253600400006 
Formation of pentanuclear copper(II) complexes with serine hydroxamic acid (Serha) and threonine hydroxamic acid (Thrha) was studied in solution by electrospray ionization mass spectrometry (ESI-MS), absorption spectrophotometry and proton NMR spectroscopy. The presence of lanthanide(III) ions is essential for the self-assembly of the 15-metallacrown-5 compounds. The positive mode ESI-MS spectra of the solutions containing Serha or Thrha, copper(H), and lanthanide(HI) ions (Ln = La, Nd, Gd) in the ratio 5:5:1 showed only the peaks that could be unambiguously assigned to the following intact molecularions: {La(NO(3))[15-MC-5](-)}(+) and {La(NO(3))(2)[15-MC-5]}(2+). The NMR spectra of the pentanuclear species revealed only one set of peaks indicating a five-fold symmetry of the complex. The UV-vis experiments revealed that upon addition of 0.2 equivalents of lanthanide(III) to the equimolar solutions containing Serha and copper(H), the self-assembly of the metallacrown structure was accomplished within 30 min. (C) 2007 Elsevier B.V. All rights reserved. 
lanthanides; hydroxamic acid; metallacrowns; rare earths