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A novel VIVO–pyrimidinone complex: synthesis, solution speciation and human ser...
Gonçalves, Gisela; Tomaz, Isabel; Correia, Isabel; Vieiros, Luís F.; Castro, M. M. C. A.; Avecilla, Fernando; Palacio, Lorena; Maestro, MiguelThe pyrimidinones mhcpe, 2-methyl-3H-5-hydroxy-6-carboxy-4-pyrimidinone ethyl ester (mhcpe, 1), 2,3- dimethyl-5-benzyloxy-6-carboxy-4-pyrimidinone ethyl ester (dbcpe, 2) and N-methyl-2,3-dimethyl-5- hydroxy-6-carboxyamido-4-pyrimidinone (N-MeHOPY, 3), are synthesized and their structures determined by single crystal X-ray diffraction. The acid–base properties of 1 are studied by potentiometric and spectrophotom...
Crystal Structure of the VV Dimer [V2O2(μ-O)(dmpp)2(OCH3)2] and Its Equilibrium...
Avecilla, Fernando; Geraldes, Carlos F. G. C.; Macedo, Anjos L.; Castro, M. Margarida C. A.The behaviour of the cyclic trimeric VV complex [V3O3(μ-O)3(dmpp)3(H2O)](H2O)2, V3L3, (L = Hdmpp = 3-hydroxy-1,2-dimethyl-4-pyridinone) was studied in methanol and methanol/water solutions by using 51V and 1D- and 2D 1H NMR spectroscopy. Red crystals, isolated from a highly concentrated methanol solution of the trimeric complex, were analysed by X-ray crystallography. The solid-state structure of the compound s...
Vanadium (IV and V) Complexes of Reduced Schiff Bases Derived from the Reaction...
Pessoa, João Costa; Marcão, Susana; Correia, Isabel; Gonçalves, Gisela; Dörnyei, Agnes; Kiss, Tamás; Jakusch, Tamás; Tomaz, IsabelThe reduced Schiff bases of salicylaldehyde [and o-vanillin (o-van)] with D,L- and L-diaminopropionic acid (DPA), designated by salDPA, and L-2,4-diaminopentanoic acid [ornithine (Orn)], designated by salOrn, as well as the VIVO2+ and VVO2+ complexes of salDPA were prepared. The compounds were characterised in the solid state and in solution. The structure of H4salDPA+Cl- was determined by X-ray diffraction. Co...
Vanadium(IV and V) Complexes of Schiff Bases and Reduced Schiff Bases Derived f...
Correia, Isabel; Pessoa, João Costa; Duarte, M. Teresa; Piedade, M. Fátima Minas da; Jackush, Tamás; Kiss, Tamás; Castro, M. Margarida C. A.Several sal2en-type reduced Schiff bases have been prepared from the reaction of 2 equiv. of salicylaldehyde (or derivatives) with ethylenediamine followed by reduction with NaBH4 and subsequently characterised. The water-soluble ligands (SO3-sal)2en and R(SO3-sal)2en (SO3-sal = salicylaldehyde-5-sulphonate) have been studied by pH potentiometry and 1H NMR spectroscopy and the protonation constants of R(SO3-sal...
N,N'-Ethylenebis(pyridoxylideneiminato) and N,N'-Ethylenebis(pyridoxylaminato):...
Correia, Isabel; Pessoa, João Costa; Duarte, M. Teresa; Henriques, Rui T.; Piedade, M. Fátima M.; Veiros, Luís F.; Jakusch, Tamás; Kiss, TamásThe Schiff base N,Nprime-ethylenebis(pyridoxylideneiminato) (H2pyr2en, 1) was synthesized by reaction of pyridoxal with ethylenediamine; reduction of H2pyr2en with NaBH4 yielded the reduced Schiff base N,Nprime-ethylenebis(pyridoxylaminato) (H2Rpyr2en, 2); their crystal structures were determined by X-ray diffraction. The totally protonated forms of 1 and 2 correspond to H6L4+, and all protonation constants wer...
X-ray Crystal Structure of a Sodium Salt of [Gd(DOTP)]5: Implications for Its S...
Avecilla, Fernando; Peters, Joop A.; Geraldes, Carlos F. G. C.The X-ray structure of the sodium salt of [Gd(DOTP)]5- shows two different chelates, [Gd(1)(DOTP)]5- and [Gd(2)(DOTP)]5-, bound at either surface of a sheet formed by a cluster of hydrated Na+ ions. Each [Gd(1)(DOTP)]5- anion binds directly to four Na+ ions of this cluster through the free oxygen atoms of the phosphonate groups of the adjacent ligand, while each [Gd(2)(DOTP)]5- unit is connected to the cluster ...
A Schiff-Base Bibracchial Lariat Ether Forming a Cryptand-like Cavity for Lanth...
González-Lorenzo, Marina; Platas-Iglesias, Carlos; Avecilla, Fernando; Geraldes, Carlos F. G. C.; Imbert, Daniel; Bünzli, Jean-Claude G.We report here a structural and photophysical study of lanthanide(III) complexes with the di-deprotonated form of the bibracchial lariat ether N,N‘-bis(2-salicylaldiminobenzyl)-1,10-diaza-15-crown-5. The X-ray crystal structures of [Ce(L2-2H)](ClO4)·0.5H2O (2) and [Sm(L2-2H)](ClO4)·C3H8O (5b) show the metal ion being nine-coordinated and deeply buried in the cavity of the dianionic receptor. Thanks to the forma...
Copper complexes with bibracchial lariat ethers: from mono- to binuclear struct...
Rodríguez-Infante, Covadonga; Esteban, David; Avecilla, Fernando; Blas, Andrés de; Rodríguez-Blas, Teresa; Mahía, Jose; Macedo, Anjos L.Copper(II) complexes with a series of bibracchial lariat ethers are described. Independently of the nature of the counterion present (nitrate or perchlorate), the lariat ether N,N'-bis(2-aminobenzyl)-1,10-diaza-15-crown-5 (L1) always forms mononuclear complexes, whereas the lariat ethers N,N'-bis(2-aminobenzyl)-4,13-diaza-18-crown-6 (L2) and N,N'-bis(2-salicylaldiminobenzyl)-4,13-diaza-18-crown-6 (L3) only give...
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