| Abstract
| - Oxovanadium complexes of Schiff base ligands with dangling tyrosine, serine, and threonine moieties can model the interplay of oxovanadates and oxovanadium cations (in particular, the VO2+ ion) with corresponding sites in proteins known to interact with vanadium species.
- Reaction of vanadyl sulfate with an aldehyde (2-hydroxy-1-naphthaldehyde (nap); 3-methoxysalicylaldehyde =o-vanillin (van)) and an amino acid carrying an OH group (l-tyrosine (l-Tyr); l-serine (l-Ser), l-threonine (l-Thr))yielded the complexes [VO(nap-d-Tyr)(H2O)] 1a, [VO(van-d,l-Tyr)(H2O)] 1c, [VO(nap-Ser)(H2O)] 2a, [VO(van-d,l-Ser)(H2O)] 2b, [VO(nap-Thr)(H2O)] 3a, and [VO(van-Thr)(H2O)] 3b. [VO(nap-l-Tyr(H2O)], 1b, was obtained fromthe reaction between [VO(nap)2] and l-TyrOMe. The crystal and molecular structures of 1a·CH3OH, 1b·CH3OH,1c·H2O, 2b·2H2O, and the Schiff base nap-d,l-TyrOMe (4) are reported. The ligands coordinate in a tridentatemanner through the phenolate component of nap or van, the imine nitrogen, and the carboxylate of the amino acid.Direct coordination of the (deprotonated) OH amino acid functionality is not observed in these complexes. Instead,the OH groups are involved in hydrogen bonding, leading, along with π−π stacking, to extended one- and three-dimensional supramolecular networks. The relevance for the interaction between oxovanadium(IV,V) and proteinshaving serine, threonine, or tyrosine at their reactive sites is addressed.
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