The effect of phenyl substituents on supramolecular assemblies containing directly linked bis-pyridylimine ligands: synthesis and structural characterisation of mononuclear nickel(II) and dinuclear silver(I) and cobalt(III) complexes of (2-pyridyl)phenylketazine
UNSPECIFIED. (2003) The effect of phenyl substituents on supramolecular assemblies containing directly linked bis-pyridylimine ligands: synthesis and structural characterisation of mononuclear nickel(II) and dinuclear silver(I) and cobalt(III) complexes of (2-pyridyl)phenylketazine. DALTON TRANSACTIONS (11). pp. 2149-2155. ISSN 1477-9226Full text not available from this repository.
Official URL: http://dx.doi.org/10.1039/b211006g
The effects of phenyl substituents introduced at the imine carbon of directly-linked bis-pyridylimine ligands is investigated. With octahedral metals the (2-pyridyl) phenylketazine ligand acts as an N-3 donor ligand with a non-coordinated imine unit. The triple-helical [M2L3](4+) complexes (observed with the unsubstituted ligand and in which the ligand uses all four nitrogen atoms) are not observed. A mononuclear [NiL2](2+) complex containing mer-coordinated N-3 ligands and a dinuclear [Co2L2 (OAc)(OH)(2)](3+) containing fac-coordinated ligands are structurally characterised. With silver(I) the library of supramolecular architectures observed for the unsubstituted ligand is driven to a single double-helical architecture by the presence of the phenyl substituents. A dimeric [Ag2L2](2+) double-helical cation is structurally characterised. In addition to the N-4 coordination afforded by the ligands, one of the silver centres in each helicate forms a short contact to a methanol solvent or a tetrafluoroborate anion. Although the double-helical structure can support the addition of four phenyl substituents, it appears that the triple-helical structure is unable to accommodate the steric requirements of six phenyl substituents. Thus in this system, the phenyl substituents destabilise the triple-helical architectures but stabilise double-helical architectures (relative to the alternative competing structures).
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry|
|Journal or Publication Title:||DALTON TRANSACTIONS|
|Publisher:||ROYAL SOC CHEMISTRY|
|Number of Pages:||7|
|Page Range:||pp. 2149-2155|
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