Ligand modifications for tailoring the binuclear microenvironments in Schiff-base calixpyrrole pacman complexes.
The synthesis and structures of two new octadentate, Schiff-base calixpyrrole macrocycles are presented in which modifications at the meso-substituents (L(1)) or the aryl spacer between the two pyrrole-imine donor compartments (L(2)) are introduced. The outcomes of these changes are highlighted in the structures of binuclear Pacman complexes of these macrocycles, [M(2)(L(1))] and [M(2)(L(2))]. Both palladium and cobalt complexes of the fluorenyl-meso-substituted macrocycle H(4)L(1) adopt rigid, but laterally twisted geometries with enclosed bimetallic microenvironments; a consequence of this spatial constraint is an exo-exo-bonding mode of pyridine in the dicobalt complex [Co(2)(py)(2)(L(1))]. In contrast, the use of an anthracenyl backbone between the two donor compartments (H(4)L(2)) generates a binuclear palladium complex in which the two PdN(4) environments are approximately cofacial and separated by 5.3 A, so generating a bimetallic complex that is structurally very similar to binuclear compounds of cofacial diporphyrins.
Askarizadeh
Elham
E
EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK.
Devoille
Aline M J
AM
Boghaei
Davar M
DM
Slawin
Alexandra M Z
AM
Love
Jason B
JB
D018360:Crystallography, X-Ray; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry
D008024:Ligands; D009942:Organometallic Compounds; D011758:Pyrroles; D012545:Schiff Bases