Hydrogen and copper ion-induced molecular reorganizations in scorpionand-like ligands. A potentiometric, mechanistic, and solid-state study.
Two aza scorpionand-like macrocycles (L2 and L3) have been prepared. L2 consists of a tren amine with two of its arms cyclizized with a 2,6-bis(bromomethyl)pyridine. In L3, the remaining pendant arm has been further functionalized with a fluorophoric naphthalene group. X-ray data on the compounds [H(L3)]ClO4.H2O (1) and [H3(L3)](H2PO4)3.H2O (2) as well as solution studies (pH-metry, UV-vis, and fluorescence data) show the movement of the pendant arm as a result of the protonation degree of the macrocycles and of the formation of intramolecular hydrogen bonds. X-ray data on the complexes [Cu(L2)](ClO4)2]2.H2O (3) and [Cu(L3)](ClO4)2 (4) and solution studies on Cu2+ coordination show the implication of the nitrogen of the arm in the binding to the metal ion. Kinetic studies on the decomposition and formation of the Cu2+ complexes provide additional information about the pH-dependent molecular reorganizations. Moreover, the obtained information suggests that the kinetics of the tail on/off process is essentially independent of the lability of the metal center.
Verdejo
Begoña
B
Departamento de Química Inorgánica, Instituto de Ciencia Molecular, Universidad de Valencia, Edificio de Institutos de Paterna, Apdo 22085, 46071 Valencia, Spain.
Ferrer
Armando
A
Blasco
Salvador
S
Castillo
Carmen Esther
CE
González
Jorge
J
Latorre
Julio
J
Máñez
M Angeles
MA
Basallote
Manuel García
MG
Soriano
Conxa
C
García-España
Enrique
E
D003300:Copper / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D017976:Phosphorus Acids / Q000737:chemistry; D011199:Potentiometry; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D007477:Ions; D008024:Ligands; D017976:Phosphorus Acids; D014867:Water; D003300:Copper; D006859:Hydrogen