Syntheses of novel tris(pyrid-2-yl) and tris(2,2'-bipyrid-6-yl) methanol derivatives and their coordination chemistries.

Singh, Neha. 2008. Syntheses of novel tris(pyrid-2-yl) and tris(2,2'-bipyrid-6-yl) methanol derivatives and their coordination chemistries. PhD Thesis, Cardiff University.

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Abstract

The work presented in this thesis describes the synthesis, structure and stability of a range of tris(2-pyrid-2-yl) and tris(2,2'-bipyrid-6-yl)methanol derivatives and their coordination chemistries with some divalent transition metals. A number of different synthetic strategies are investigated in order to synthesise these tripodal ligands in reasonable yields. The routes that proved to be most successful involved the carbonylation and Stille coupling of 6- bromopyrid-2-yl derivatives in the presence of a palladium catalyst, tetrakis triphenylphosphine palladium(0) (Pd(PPh3)4). By adapting the method published by Peng and Aguilar, mono, bis and tris(6-sodium carboxylate pyrid-2-yl)methanol derivatives were successfully synthesised. These led to the introduction of a number of novel mono, bis and tris(6-methylcarboxypyrid-2-yl)methanol intermediates that were also successfully characterised by crystallographic studies. The solid-state structures reveal some interesting topologies of the ligand due to the flexibility introduced to the coordination sphere by the methyl ester groups. Further spectroscopic analyses involve ultra-violet, infra-red, nuclear magnetic resonance spectroscopy, mass spectrometry, elemental analysis and electrochemisty. The work presented by Leize et al. led to the syntheses of mono, bis and tris(2,2'-bipyrid-6-yl)methanol derivatives. Again some interesting topologies are revealed from their crystallographic data of their metal complexes. A number of geometries are identified throughout this study. Interestingly, these tripodal ligands reveal trigonal prismatic coordination with Zn and Fe metal centres whereas the Cu(II) ion of d9 configuration only exhibits one Jahn-Teller distortion (a distorted octahedron) with only one of the ligands synthesised, the (2,2'-bipyrid-6-yl)bis(pyrid-2-yl)methanol. The other Cu geometries discussed are square pyramidal or trigonal bipyramidal. Typically the Ni(II) complexes characterised exhibit pseudo-octahedral coordination with solvent molecules occupying the apical position.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
ISBN:	9781303183331
Date of First Compliant Deposit:	30 March 2016
Last Modified:	12 Feb 2016 23:12
URI:	https://orca.cardiff.ac.uk/id/eprint/54339

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