Endohedral functionalization via supercritical CO2 was undertaken in orderto produce encapsulation of organometallic systems that are difficult toencapsulate otherwise due to either their large size or extreme air sensitivity.Organometallic molecular systems from the prophyrin and phthalocyaninefamilies (such as NiPc, ClAlPc and NiTPP) were successfully encapsulatedinside of nanotubes with relatively large diameters (centred around 2 nm).This was assessed by a combination of high resolution transmission electronmicroscopy (HRTEM) and Raman spectroscopy. HRTEM revealed previouslyunreported ordering of NiTPP, a large planar molecule, in row-like assembliesinside nanotubes of diameters that match best the geometrical sizeof the molecule (2 nm), highlighting the role of confinement in promoting assembly.Using both endohedral and exohedral functionalization with NiTPP,ClAlPc and NiPc molecules provided a set of systems differing by only onespecific parameter (e.g. central ion or body type, or size of the HOMO-LUMOgap), or comparatively affected the ability to bind to the nanotubes- the associated changes in the electronic properties of the nanotubes wererevealed by resonant Raman spectroscopy. These changes were interpretedin terms of ability of the guest molecular species to produce charge transferto/from the nanotube, and/or induce structural strain.
|Date of Award||7 Nov 2014|
|Supervisor||Adelina Ilie (Supervisor)|