Premium
Metal Complexation of a D ‐Ribose‐Based Ligand Decoded by Experimental and Theoretical Studies
Author(s) -
Cisnetti Federico,
Maréchal JeanDidier,
Nicaise Magali,
Guillot Régis,
Desmadril Michel,
Lambert François,
Policar Clotilde
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201200322
Subject(s) - chemistry , ligand (biochemistry) , metal , chelation , octahedron , moiety , crystallography , stereochemistry , computational chemistry , inorganic chemistry , crystal structure , organic chemistry , receptor , biochemistry
A combination of experimental and theoretical methods have been used to elucidate the complexation properties of a new sugar‐derived hexadentate ligand, namely methyl 2,3,4‐tri‐ O ‐(2‐picolyl)‐β‐ D ‐ribopyranoside ( L ). The coordination bond lengths in the complexes with Mn II , Co II , Ni II , and Zn II show substantial deviations from ideal octahedra with deformation towards trigonal‐prismatic geometries, which is indicative of a conformationally constrained ligand. The metal‐cation–ligand interactions were studied for L and the acyclic analogue L′ [1,2,3‐tri‐ O ‐(2‐picolyl)‐1,2,3‐propanetriol] by spectroscopic methods and isothermal calorimetric titrations for the series Mn II , Co II , Ni II , Zn II , and Cu II . The results indicate a stabilization of the complexes obtained with L compared with L′ , depending on the nature of the metal. Molecular modeling studies showed that the presence of the sugar moiety strongly favors conformations compatible with metal binding, which suggests an entropic origin of the stabilization of L complexes with regards to L′ complexes. Moreover, the differences in the metal chelation profiles of L and L′ are related to the constraints in the sugar group in the metal‐bound structures. This study shows that foreseeing the degree of preorganization of flexible ligands may drive the design of a new generation of chelating compounds.