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Neil B. McKeown: Research

I work at the interface between organic synthesis and materials chemistry, designing and preparing novel molecules and polymers with interesting physical properties. Many, but not all, of these substances contain phthalocyanine (Pc) - a common blue colorant - which has fascinating electronic, optical and self-ordering properties. Current projects include:

Phthalocyanine-containing dendrimers.

Dendrimers are hyperbranched macromolecules of uniform molecular mass. We have prepared Pcs with two axial or four peripheral dendritic substituents. Some of these materials have yielded beautiful X-ray crystal structures (left and right). The control over molecular association afforded by the dendrimer substituents and the glassy nature of the resulting films make them suitable for optical applications. We are also using dendrimers for drug delivery in collaboration with the Pharmacy Department

Phthalocyanine Network Polymers.

On-going research involves the incorporation of the Pc macrocycle into network polymers in which the relative orientation of neighbouring Pc rings is controlled by two spiro centres (see below) in the linking group. This results in a 2-D (planar or sheet) polymer (left) from the formation of phthalocyanine units from the bisphthalonitrile shown on the right. Recent results have shown that materials with very high surface area (e.g 1000 m2g-1) can be prepared using linkers containing a single spiro-centre. These materials have excellent characteristics for heterogeneous catalysis and adsorption. For more information use the following link:

http://www.maninv.com/technologies/technologies.htm

Phthalocyanine Liquid Crystals.

Over the last few years we have synthesised many Pcs which form columnar liquid crystals. These materials are of interest for their ability to conduct electricity or light energy along the axis of the columns (left) due to the non-covalent interactions between neighbouring Pc cores. Optical microscopy reveals the beautiful phases displayed by these molecules (right).

Spiropolymers.

These are a subclass of ladder polymers in which adjacent rings share a common atom. The uniformity and rigidity of these materials tends to make them highly insoluble, however, we are preparing novel spiropolyketals, from nonlinear diketones, which possess high solubility because of their randomly contorted structures (e.g. left). Hyperbranched spiropolymers can be made by incorporating compounds which contain six hydroxyl groups (right).

Photopolymerisable liquid crystalline styrenes.

Photopolymerisation of oriented liquid crystalline monomers is an excellent method of 'freezing' the molecular order of a liquid crystal into the solid phase to produce films with useful optical properties. Usually this is achieved with acrylate derivatives but we have prepared a novel family of liquid crystal monomers based on styrene (e.g. left). Films derived from the photopolymerisation of the nematic phase (right) and the chiral nematic phase have been prepared.

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	Phthalocyanine-containing dendrimers. Dendrimers are hyperbranched macromolecules of uniform molecular mass. We have prepared Pcs with two axial or four peripheral dendritic substituents. Some of these materials have yielded beautiful X-ray crystal structures (left and right). The control over molecular association afforded by the dendrimer substituents and the glassy nature of the resulting films make them suitable for optical applications. We are also using dendrimers for drug delivery in collaboration with the Pharmacy Department
	Phthalocyanine Network Polymers. On-going research involves the incorporation of the Pc macrocycle into network polymers in which the relative orientation of neighbouring Pc rings is controlled by two spiro centres (see below) in the linking group. This results in a 2-D (planar or sheet) polymer (left) from the formation of phthalocyanine units from the bisphthalonitrile shown on the right. Recent results have shown that materials with very high surface area (e.g 1000 m2g-1) can be prepared using linkers containing a single spiro-centre. These materials have excellent characteristics for heterogeneous catalysis and adsorption. For more information use the following link: http://www.maninv.com/technologies/technologies.htm
	Phthalocyanine Liquid Crystals. Over the last few years we have synthesised many Pcs which form columnar liquid crystals. These materials are of interest for their ability to conduct electricity or light energy along the axis of the columns (left) due to the non-covalent interactions between neighbouring Pc cores. Optical microscopy reveals the beautiful phases displayed by these molecules (right).
	Spiropolymers. These are a subclass of ladder polymers in which adjacent rings share a common atom. The uniformity and rigidity of these materials tends to make them highly insoluble, however, we are preparing novel spiropolyketals, from nonlinear diketones, which possess high solubility because of their randomly contorted structures (e.g. left). Hyperbranched spiropolymers can be made by incorporating compounds which contain six hydroxyl groups (right).
	Photopolymerisable liquid crystalline styrenes. Photopolymerisation of oriented liquid crystalline monomers is an excellent method of 'freezing' the molecular order of a liquid crystal into the solid phase to produce films with useful optical properties. Usually this is achieved with acrylate derivatives but we have prepared a novel family of liquid crystal monomers based on styrene (e.g. left). Films derived from the photopolymerisation of the nematic phase (right) and the chiral nematic phase have been prepared.