New metal organic frameworks incorporating the ditopic macrocyclic ligand dipyridyldibenzotetraaza[14]annulene

Mulyana, Y., Lindoy, L.F., Kepert, C.J., McMurtrie, J., Parkin, A., Turner, P., Wei, G. and Wilson, J. G. (2011) New metal organic frameworks incorporating the ditopic macrocyclic ligand dipyridyldibenzotetraaza[14]annulene. Journal of Inclusion Phenomena and Macrocyclic Chemistry, 71(3-4), pp. 455-462. (doi: 10.1007/s10847-011-0007-6)

Abstract

The synthesis and crystal structures of three new metal organic frameworks of type [Zn(L-2H)](n) (1), {[ZnLCl2](CH3CN)(0.5)(DMF)(0.5)(H2O)(0.5)}(n) (2) and {[CdL (DMF)(NO3)(2)]center dot DMF}(n) (3), all based on the dipyridyl-derivatised macrocycle, dipyridyldibenzotetraaza[14]annulene (L), are reported along with the X-ray structure of the protonated metal-free ligand as its perchlorate salt, [(HL) (ClO4)](n) (4). In [Zn(L-2H)](n), the zinc ion occupies the macrocyclic cavity, being bound to the N-4-donor set of the macrocyclic ring in its doubly deprotonated form. Each zinc atom is also axially bound by a pyridyl moiety from an adjacent complex, resulting in formation of an infinite one-dimensional chain of the 'herringbone' type in which pairs of macrocyclic complexes interact via face-to-face pi-pi stacking interactions. In contrast, the zinc ion in {[ZnLCl2] (CH3CN)(0.5)(DMF)(0.5)(H2O)(0.5)}(n) does not occupy the macrocyclic cavity but is bound to a pyridyl nitrogen from two ligands such that it acts as a bridge between macrocyclic units and results in the generation of a one-dimensional chain. Two chloro ligands also bind to each zinc centre to yield a distorted tetrahedral coordination geometry. Offset pi-pi stacking occurs between adjacent chains involving alternate macrocycles in each chain, giving rise to a zig-zag arrangement. Pairs of interacting chains pass through the above-mentioned chains to generate further pi-pi stacking to yield an overall three-dimensional structure that contains large ellipsoidal-shaped channels. In {[CdL(DMF)(NO3)(2)]center dot DMF}(n) the cadmium ion again does not occupy the macrocyclic cavity but acts as a bridge between macrocycles to once again afford a linear chain structure. Each cadmium is bound to two pyridyl groups (arising from different molecules of L), two nitrato ligands and one oxygen-bound dimethylformamide molecule to yield a distorted pentagonal bipyramidal coordination geometry. The protonated ligand, [(HL)(ClO4)](n), adopts a linear chain structure in which one pyridyl group is protonated and interacts intermolecularly via a hydrogen bond with the non-protonated pyridyl group of an adjacent macrocyclic unit to yield a hydrogen-bonded linear chain structure.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Parkin, Dr Andrew
• Authors: Mulyana, Y., Lindoy, L.F., Kepert, C.J., McMurtrie, J., Parkin, A., Turner, P., Wei, G., and Wilson, J. G.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Inclusion Phenomena and Macrocyclic Chemistry
• ISSN: 1388-3127
• ISSN (Online): 1573-1111
• Published Online: 19 July 2011