160895-40-9Relevant academic research and scientific papers
Stepwise Approach to Bimetalic Porphyrin Hosts: Spatially Enforced Coordination of Nickel (II) Porphyrin
Vidal-Ferran, Anton,Bampos, Nick,Sanders, Jeremy K. M.
, p. 6117 - 6126 (2008/10/09)
The synthesis of the Zn3 1,1,2-trimer Zn33 and the NiZn2 1,1,2-trimer NiZn23 by a stepwise convergent route is described. A large affinity for Py3T by both cyclic 1,1,2-trimers, Zn33 or NiZn23, with respect to the linear trimers, provides a thermodynamic driving force for the templated cyclization of the new host molecules, which were fully characterized by NMR spectroscopy (COSY and NOESY). The binding properties of several pyridine-containing bidentate and tridentate ligands have been investigated in order to probe the shape and the size of the cavity of the host molecule. Both Py2Pr and Py2Py bind very strongly to Zn33 and NiZn23 (ligand affinities in CH2Cl2 at 25°C, > 108 M-1), while the tridentate ligand Py3T binds to both Zn33 and NiZn23 with a very high binding constant (ligand affinities in CH2Cl2 at 25°C, >109 M-1). This unexpected result for NiZn23 suggests that the cavity-enforced effective molarity of the third pyridyl of Py3T at the Ni site is high enough to form the first example of a stable 1:1 Ni(II)-pyridyl complex. The resulting Ni(II) paramagnetic complex has been characterized by NMR; the temperature dependence deviates slightly from ideal Curie behavior.
