This article details the preparation, photophysical and electrochemical investigation of four novel polyaromatic squareplanar platinum(II) bis(acetylide) complexes, incorporating either a planar hexa-peri-hexabenzocoronene (L 2 ) or its uncyclised ethynyl-hexaphenylbenzene precursor (L 1 ). Complexes in both cis and transwere successfully prepared and fully characterised. The low-energy bands of the UV/Vis absorption spectra for the uncyclised family (L 1 , C 1 , T 1 ) and for

We describe a series of functionalized N-containing heterosuperbenzenes, created with a view to investigating the strategic role of methoxy substituents in (i) promoting cyclodehydrogenation and (ii) tuning the electronic properties and (iii) the supramolecular order in the resultant fused products.The dominance of inorganic semiconductors in the manufacture of optoelectronic devices and field effect transistors is gradually being undermined by the emergence of functional organic materials. [1][2][3] Although electron mobility remains a challenge, these represent lightweight, flexible alternatives that are more readily processed using solution-based methods. Within this arena, the opportunities proffered by the exceptional electronic and physical properties of graphene and its derivatives are undeniable. [4][5][6] As many aspects in the formation of large graphitic sheets are difficult to control, synthetic chemists have pioneered routes to nanographenes with impressive and varying dimensions, and an array of peripheral substituents. 7-10 Dependent on the latter are a range of material characteristics e.g. the nature of the p-p interactions, HOMO-LUMO gaps and film-forming capabilities. [11][12][13][14] The ability to manufacture graphene systems to such specificity is notably absent in exfoliation 15 /epitaxial growth 16 processes, and this makes the further development of bottom-up synthetic methodologies for the formation of next-generation and heteroatomcontaining graphenes all the more important. 10,17 Oxidative cyclodehydrogenation is a key step in the chemical formation of planarised ring systems. All-carbon systems cyclise rapidly, while heteroatom-containing polyphenylenes appear to adopt a more complex mechanism for ring closure, e.g. both partially and fully fused species tend to be generated in a single reaction. [18][19][20] Electron donating substituents both direct and promote CC bond formation under cyclodehydrogenation conditions. 21,22 Tuning the intramolecular properties of graphenes is one step in the search for technology-enabling materials. Also essential is the ability to exert some supramolecular control of structure. Disc-like molecules tend to aggregate in columnar p-p stacks which can be either enhanced or perturbed by peripheral units e.g. long chain alkyl substituted hexaperihexabenzocoronenes frequently exhibit liquid crystalline behaviour, 2 whereas their iodo-or tert-butyl-functionalised derivatives give rise to Bernal-stacked crystalline dimers. 23 This work reveals how the combination of heteroatom doping (as pioneered by Draper et al.), 17,24-26 with H-bonding peripheral substituents, can unlock some exciting new applications for nanographene materials by controlling the outcome of the synthetic process and the HOMO-LUMO gaps and intermolecular order of the end-products.The synthetic methods used to form the precursor polyphenylenes were modifications of published routes involving cyclopentadienones (generated via two-fold Knoevenagel condensations) and their subsequent [2+4] D...

This work describes the synthesis and characterisation of a new series of polyphenylenes with up to four ferrocenyl moieties. The synthetic route involves the preparation of a number of novel precursors. Cyclopentadienones, generated from the two-fold Knoevenagel condensation of di-ferrocenyl propanones and diketones, are used in [2 + 4] Diels-Alder cycloadditions with appropriately substituted acetylenes. 13 is amongst the compounds isolated. It is the largest ferrocenyl-supported polyaromatic hydrocarbon (PAH) to date. Prepared via a Sonogashira cross-coupling reaction between ethynyl-Fc and iodo-HBC, it comprises a hexa-peri-hexabenzocoronene (HBC) core linked via acetylene to a ferrocenyl unit (Fc). The electrochemical and absorption properties of the ferrocenyl-polyphenylenes and the fully conjugated 13 are discussed. The NLO data for 13, determined by hyper Rayleigh scattering techniques, are compared to those of similar fulleryl-based compounds in the literature.