Novel thiophene based macrocycles

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Sloman, Z.S., 1999. Novel thiophene based macrocycles. PhD, Nottingham Trent University.

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Abstract

A range of macrocyclic complexes was prepared utilising α,ω-bis(2-formyl-3- oxythienyl)alkanes. Macrocyclic [1+1] metal ion complexes (metal ion = Ni(II), Co(II)) were prepared via condensation of the ?,?-bis(2-formyl-3-oxythienyl)alkane with ethylenediamine (en) and subsequent addition of the metal ion to sequester the macrocyclic ligand. Macrocyclic [2+2] metal ion complexes were prepared via condensation of the α,ω-bis(2-formyl-3-oxythienyl)alkane with metal ion- ethylenediamine complexes. Complete condensation only occurred with [Ni(en)2Cl2] as the template.

New routes that did not result in macrocyclic products are discussed and the new compounds they produced are presented.

The Mannich reaction was utilised for the preparation of macrocycles from α,ω-bis(3-oxythienyl)alkanes, formaldehyde and N,N'-dibenzylalkyldiamines. These compounds were obtained in good yields without the need for high dilution or column chromatography. The compounds obtained were crystalline and stable to X-radiation.

The crystal structure determination of two of the compounds was undertaken. The 15- membered ring macrocycle C29H32N2O2S2 (M1) crystallises in the monoclinic space group P21/c with cell dimensions of α= 12.5043Å, b = 11.2997 Å, c = 19.8022 Å, β = 113.34°, a, γ = 90°. The structure was determined using a STOE Stadi-2-circle diffractometer with data collected from two crystals and refined with Iobsd > 4α (I) using unit weights to R = 0.0683. The structure has an unusual non-planar geometry and a non-bonded S...N interaction as well as several probable C-H...O hydrogen bonds.

The 14-membered ring macrocycle C28H30N2O2S2 (M2) crystallises in the orthorhombic space group Pca21 with cell dimensions of α = 22.733 Å, b= 11.397 Å, c = 20.115 Å, α, β, γ= 90°. There are two macrocycles per asymmetric unit which are related via non- crystallographic symmetry which possibly gives rise to the disorder shown on the X-ray photographs. The structure was determined using a STOE Stadi-2-circle diffractometer and refined with Iobsd > 6a (I) using unit weights to R = 0.1347. The asymmetric unit consists of two macrocycles with similar geometries, which are discussed and contrasted with the 15-membered macrocycle.

Unit cell and space group data were obtained for two acyclic ligands incorporating two thiophene rings, one potentially pentadentate with five oxygen atoms and one potentially tetradentate with two oxygen and two nitrogen atoms.

A nickel(II) complex of Ml was molecularly modelled using CHEM-X+ and the preferable coordination geometry of the macrocycle is discussed.

Item Type:

Thesis

Creators:

Sloman, Z.S.

Date:

1999

ISBN:

9781369323689

Identifiers: