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Lanthanide( III )‐Induced Conversion of 12‐Metallacrown‐4 to 5‐Metallacrown‐5 Complexes in Solution
Author(s) -
Pacco Antoine,
ParacVogt Tatja.,
van Besien Els,
Pierloot Kristine,
GörllerWalrand Christiane,
Binnemans Koen
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200500241
Subject(s) - chemistry , lanthanide , ligand (biochemistry) , proton nmr , circular dichroism , crystallography , copper , electrospray ionization , ion , inorganic chemistry , stereochemistry , organic chemistry , biochemistry , receptor
The conversion of 12‐metallacrown‐4 complexes with copper( II ) in the central cavity to 15‐metallacrown‐5 complexes with lanthanide( III ) ions in the central cavity upon addition of trivalent lanthanide ions was analysed in solution by electrospray ionisation mass spectrometry (ESI‐MS), absorption spectrophotometry, circular dichroism and proton NMR spectroscopy. In all cases, copper( II ) ions were the ring metals. The lanthanide‐induced shifts of the proton resonances in the NMR spectra of different lanthanide( III )‐containing 15‐metallacrown‐5 complexes with tyrosinehydroximate ligands were studied. The dynamics of ligand exchange of α‐aminohydroximate‐based lanthanide( III )‐containing 15‐metallacrown‐5 complexes were studied in methanol solutions. The ring structure of the 12‐metallacrown‐4 complex that acts as starting compound for the formation of the 15‐metallacrown‐5 complexes was optimized by DFT methods using alaninehydroximate as a model ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)