0000000001310869
AUTHOR
Andrés G. Algarra
Equilibrium and kinetics studies on bibrachial lariat aza-crown/Cu(II) systems reveal different behavior associated with small changes in the structure
Abstract The high-yield synthesis of a new bibrachial lariat azacrown constituted by two tris(2-aminoethyl)amine (tren) units functionalized in one of its arms with a 4-methylquinoline group linked by dimethylene pyridine spacers (L2) is reported for the first time. The speciation studies show formation of mono- and binuclear Cu2+ complexes of similar stability. Comparisons are established with the complexes formed by the precursor tren-quinoline derivative (L4) and with the previously reported ligands containing naphthalene instead of quinoline as the fluorophore (L1, L3). The kinetics of formation and decomposition of Cu2+ complexes with L1 and L2 has been studied. For L1, the acid-promot…
Hydrogen and Copper Ion Induced Molecular Reorganizations in Two New Scorpiand-Like Ligands Appended with Pyridine Rings
The synthesis of two new ligands constituted of a tris(2-aminoethyl)amine moiety linked to the 2,6 positions of a pyridine spacer through methylene groups in which the hanging arm is further functionalized with a 2-pycolyl (L1) or 3-pycolyl (L2) group is presented. The protonation of L1 and L2 and formation of Cu(2+) complexes have been studied using potentiometric, NMR, X-ray, and kinetic experiments. The results provide new information about the relevance of molecular movements in the chemistry of this kind of so-called scorpiand ligand. The comparison between these two ligands that only differ in the position of the substituent at the arm reveals important differences in both thermodynam…
Coordination Chemistry of Cu2+ Complexes of Small N-Alkylated Tetra-azacyclophanes with SOD Activity
A new tetraaza-pyridinophane macrocycle (L1) N-alkylated with two isopropyl and one methyl groups symmetrically disposed has been prepared and its behavior compared with those of the unsubstituted pyridinophane (L3) and the related compound with three methyl groups (L2). The protonation studies show that, first, a proton binds to the central methylated amine group of L1, while, second protonation leads to a reorganization of the protons that are at this stage attached to the lateral isopropylated amines. The X-ray structure of [HL1]+ agrees with the UV–vis and NMR studies as well as with the results of DFT calculations. The stability of the Cu2+ complexes decreases on increasing the bulkine…
Synthesis, Protonation and Cu II Complexes of Two Novel Isomeric Pentaazacyclophane Ligands: Potentiometric, DFT, Kinetic and AMP Recognition Studies
The synthesis and coordination chemistry of two novel ligands, 2,6,9,12,16-pentaaza[17]metacyclophane (L1) and 2,6,9,12,16-pentaaza[17]paracyclophane (L2), is described. Potentiometric studies indicate that L1 and L2 form a variety of mononuclear complexes the stability constants of which reveal a change in the denticity of the ligand when moving from L1 to L2, a behaviour that can be qualitatively explained by the inability of the paracyclophanes to simultaneously use both benzylic nitrogen atoms for coordination to a single metal centre. In contrast, the formation of dinuclear hydroxylated complexes is more favoured for the paraL2 ligand. DFT calculations have been carried out to compare …
Geometric Isomerism in Pentacoordinate Cu2+ Complexes: Equilibrium, Kinetic, and Density Functional Theory Studies Reveal the Existence of Equilibrium between Square Pyramidal and Trigonal Bipyramidal Forms for a Tren-Derived Ligand
A ligand (L1) (bis(aminoethyl)[2-(4-quinolylmethyl)aminoethyl]amine) containing a 4-quinolylmethyl group attached to one of the terminal amino groups of tris(2-aminoethyl)amine (tren) has been prepared, and its protonation constants and stability constants for the formation of Cu(2+) complexes have been determined. Kinetic studies on the formation of Cu(2+) complexes in slightly acidic solutions and on the acid-promoted complex decomposition strongly suggest that the Cu(2+)-L1 complex exists in solution as a mixture of two species, one of them showing a trigonal bipyramidal (tbp) coordination environment with an absorption maximum at 890 nm in the electronic spectrum, and the other one bein…
CCDC 1827335: Experimental Crystal Structure Determination
Related Article: Álvaro Martínez-Camarena, Andrea Liberato, Estefanía Delgado-Pinar, Andrés G. Algarra, Javier Pitarch-Jarque, José M. Llinares, M. Ángeles Mañez, Antonio Domenech-Carbó, Manuel G. Basallote, Enrique García-España|2018|Inorg.Chem.|57|10961|doi:10.1021/acs.inorgchem.8b01492
CCDC 1827337: Experimental Crystal Structure Determination
Related Article: Álvaro Martínez-Camarena, Andrea Liberato, Estefanía Delgado-Pinar, Andrés G. Algarra, Javier Pitarch-Jarque, José M. Llinares, M. Ángeles Mañez, Antonio Domenech-Carbó, Manuel G. Basallote, Enrique García-España|2018|Inorg.Chem.|57|10961|doi:10.1021/acs.inorgchem.8b01492
CCDC 1423684: Experimental Crystal Structure Determination
Related Article: Salvador Blasco, Begoña Verdejo, M. Paz Clares, Carmen E. Castillo, Andrés G. Algarra, Julio Latorre, M. Angeles Máñez, Manuel G. Basallote, Conxa Soriano and Enrique García-España|2010|Inorg.Chem.|49|7016|doi:10.1021/ic100609h
CCDC 1827336: Experimental Crystal Structure Determination
Related Article: Álvaro Martínez-Camarena, Andrea Liberato, Estefanía Delgado-Pinar, Andrés G. Algarra, Javier Pitarch-Jarque, José M. Llinares, M. Ángeles Mañez, Antonio Domenech-Carbó, Manuel G. Basallote, Enrique García-España|2018|Inorg.Chem.|57|10961|doi:10.1021/acs.inorgchem.8b01492