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Vanadium(IV and V) Complexes of Schiff Bases and Reduced Schiff Bases Derived from the Reaction of Aromatic o‐Hydroxyaldehydes and Diamines: Synthesis, Characterisation and Solution Studies
| Content Provider | Semantic Scholar |
|---|---|
| Author | Correia, Isabel Pessoa, João Costa Duarte, Maria Teresa Piedade, M. Fátima M. Jackush, Tamás Kiss, Tamás Castro, M. Margarida C. A. Geraldes, Carlos F. G. C. Avecilla, Fernando |
| Copyright Year | 2005 |
| Abstract | Several sal 2 en-type reduced Schiff bases have been prepared from the reaction of 2 equiv. of salicylaldehyde (or derivatives) with ethylenediamine followed by reduction with NaBH 4 and subsequently characterised. The water-soluble ligands (SO 3 -sal) 2 en and R(SO 3 -sal) 2 en (SO 3 -sal = salicylaldehyde-5-sulphonate) have been studied by pH potentiometry and 1 H NMR spectroscopy and the protonation constants of R(SO 2 -sal) 2 en have been determined. The Schiff bases are more susceptible to hydrolysis than the corresponding reduced Schiff bases. The crystal structures of H 2 (o-van) 2 en and KH(o-van) 2 en (o-van = o-vanillin) have been determined by X-ray diffraction. The vanadium(IV) complexes have been prepared and characterised by magnetic measurements and IR, UV/Vis and EPR spectroscopy. The colours, magnetic susceptibilities and IR spectra of the new vanadium(IV) complexes of the reduced Schiff bases now obtained suggest oligomeric/polymeric structures for the compounds while the corresponding V I V O-Schiff-base complexes are monomeric. The complexation of (V I V O] 2 + and (V V O 2 ] + with R(SO 3 -sal) 2 en in aqueous solution has been studied by pH potentiometry, UV/Vis as well as by EPR spectroscopy for the V I V O system and 1 H and 5 1 V NMR spectroscopy for the V V O 2 system. Complex formation constants have been determined and binding modes have been proposed. N,N'-ethylenebis(pyridoxylaminato) (Rpyr 2 en) has also been obtained and the structure of Na(V V O 2 (Rpyr 2 en)].CH 3 OH.3H 2 O determined by X-ray diffraction. The Rpyr 2 en 2 - ligand coordinates through both the N-amine and O-phenolate moieties in a symmetrical α-cis type coordination mode, i.e. with both O-phenolato donors cis to the O-oxo atoms and trans to each other. |
| Starting Page | 732 |
| Ending Page | 744 |
| Page Count | 13 |
| File Format | PDF HTM / HTML |
| DOI | 10.1002/ejic.200400481 |
| Volume Number | 2005 |
| Alternate Webpage(s) | https://isabelcorreia.weebly.com/uploads/1/1/1/2/11123979/12_ejib_2005.pdf |
| Alternate Webpage(s) | https://estudogeral.sib.uc.pt/bitstream/10316/8126/1/obra.pdf |
| Alternate Webpage(s) | https://doi.org/10.1002/ejic.200400481 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
