(Dibenzo-18-crown-6)(2-phenylamidopyridine)potassium(I)

William Clegg,Stephen T Liddle

doi:10.1107/s1600536804023360

William Clegg, Stephen T Liddle

Open Access

https://doi.org/10.1107/s1600536804023360

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Abstract

The title complex, [Rb(C11H9N2)(C20H24O6)], has potassium in an irregular eightfold coordination, with a hexadentate crown ether ligand and a chelating bidentate amidopyridine ligand, each occupying one hemisphere of the coordination. The chelate KNCN ring is slightly folded, and the two rings of the amidopyridine ligand are not coplanar, because of steric interaction of H atoms on the rings. The K—N(amido) bond is shorter than the K—N(pyridine) bond. The coordination of the crown ether to potassium is less symmetrical than that for the analogous rubidium complex, reflecting a poorer size match for K+ in this coordination site.

Highlights

We present here the structure of the analogous potassium complex,K(L), (I)
These complexes were prepared as part of a study of crown-ether-supported complexes of alkali metals with amide ligands, and were investigated speci®cally for comparison with the complexes with 18-crown-6 (Liddle et al, 2004; Liddle & Clegg, 2003)
The Rb complexes with the two different crown ethers are structurally very similar, there is a marked difference for the K complexes

Summary

Introduction

The title complex, [Rb(C11H9N2)(C20H24O6)], has potassium in an irregular eightfold coordination, with a hexadentate crown ether ligand and a chelating bidentate amidopyridine ligand, each occupying one hemisphere of the coordination. The chelate KNCN ring is slightly folded, and the two rings of the amidopyridine ligand are not coplanar, because of steric interaction of H atoms on the rings. The coordination of the crown ether to potassium is less symmetrical than that for the analogous rubidium complex, reecting a poorer size match for K+ in this coordination site.

Results

Conclusion