Acta Crystallographica Section C

Crystal Structure Communications

Volume 64, Part 5 (May 2008)

metal-organic compounds

 

Three overcrowded zinc(II) complexes with potentially hexadentate polypyridyl ligands

A. Hazell, O. Mønsted, J. C. Rasmussen and H. Toftlund

Abstract: In each of [N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine-⁶N]zinc(II) bis(perchlorate) 0.67-hydrate, [Zn(C₂₆H₂₈N₆)](ClO₄)₂·0.67H₂O, (I), [N,N,N'-tris(2-pyridylmethyl)-N'-(2-quinolylmethyl)ethane-1,2-diamine-⁶N]zinc(II) bis(perchlorate), [Zn(C₃₀H₃₀N₆)](ClO₄)₂, (II), and [N,N'-bis(2-pyridylmethyl)-N,N'-bis(2-quinolylmethyl)ethane-1,2-diamine-⁶N]zinc(II) bis(perchlorate) monohydrate, [Zn(C₃₄H₃₂N₆)](ClO₄)₂·H₂O, (III), the Zn atom is coordinated to all six N atoms of the ligand. Compound (I) has one complex cation in a general position and one on a twofold axis. The coordination environments are intermediate between a regular octahedron and a pentagonal bipyramid which lacks one equatorial bond; complexes (II) and (III) are shown to be closer to the latter description. The quinolyl groups are in equatorial positions and the deviation from octahedral geometry increases with the number of these groups. This study demonstrates the systematic changes in the geometry at the central Zn atom as the overlap between the ligands increases.

Formula: [Zn(C₂₆H₂₈N₆)](ClO₄)₂·0.67H₂O, [Zn(C₃₀H₃₀N₆)](ClO₄)₂ and [Zn(C₃₄H₃₂N₆)](ClO₄)₂·H₂O

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