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Design and Synthesis of Binucleating Macrocyclic Clefts Derived from Schiff‐Base Calixpyrroles
Author(s) -
Givaja Gonzalo,
Volpe Manuel,
Leeland James W.,
Edwards Michael A.,
Young Thomas K.,
Darby S. Barnie,
Reid Stuart D.,
Blake Alexander J.,
Wilson Claire,
Wolowska Joanna,
McInnes Eric J. L.,
Schröder Martin,
Love Jason B.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600989
Subject(s) - schiff base , base (topology) , chemistry , mathematics , stereochemistry , mathematical analysis
The syntheses, characterisation and complexation reactions of a series of binucleating Schiff‐base calixpyrrole macrocycles are described. The acid‐templated [2+2] condensations between meso ‐disubstituted diformyldipyrromethanes and o ‐phenylenediamines generate the Schiff‐base pyrrolic macrocycles H 4 L 1 to H 4 L 6 upon basic workup. The single‐crystal X‐ray structures of both H 4 L 3 ⋅2 EtOH and H 4 L 6 ⋅H 2 O confirm that [2+2] cyclisation has occurred, with either EtOH or H 2 O hydrogen‐bonded within the macrocyclic cleft. A series of complexation reactions generate the dipalladium [Pd 2 ( L )] ( L = L 1 to L 5 ), dinickel [Ni 2 ( L 1 )] and dicopper [Cu 2 ( L )] ( L = L 1 to L 3 ) complexes. All of these complexes have been structurally characterised in the solid state and are found to adopt wedged structures that are enforced by the rigidity of the aryl backbone to give a cleft reminiscent of the structures of Pacman porphyrins. The binuclear nickel complexes [Ni 2 (μ‐OMe) 2 Cl 2 (HOMe) 2 (H 4 L 1 )] and [Ni 2 (μ‐OH) 2 Cl 2 (HOMe)(H 4 L 5 )] have also been prepared, although in these cases the solid‐state structures show that the macrocyclic ligand remains protonated at the pyrrolic nitrogen atoms, and the Ni II cations are therefore co‐ordinated by the imine nitrogen atoms only to give an open conformation for the complex. The dicopper complex [Cu 2 ( L 3 )] was crystallised in the presence of pyridine to form the adduct [Cu 2 (py)( L 3 )], in which, in the solid state, the pyridine ligand is bound within the binuclear molecular cleft. Reaction between H 4 L 1 and [Mn(thf){N(SiMe 3 ) 2 } 2 ] results in clean formation of the dimanganese complex [Mn 2 ( L 1 )], which, upon crystallisation, formed the mixed‐valent complex [Mn 2 (μ‐OH)( L 1 )] in which the hydroxo ligand bridges the metal centres within the molecular cleft.