A divergent synthetic strategy for generating helical p53 peptides bearing functionalised staple linkages, allowing for efficient optimisation of cellular activity.

The atomic structure of the chains of an alkyl porphyrin (5,10,15,20-tetranonadecylporphyrin) self-assembled monolayer (SAM) at the solid/liquid interface of highly ordered pyrolytic graphite (HOPG) and 1-phenyloctane is resolved using calibrated scanning tunneling microscopy (STM), density functional theory (DFT) image simulations, and ONIOM-based geometry optimizations. While atomic structures are often readily determined for porphyrin SAMs, the determination of the structure of alkyl-chain connections has not previously been possible. A graphical calibration procedure is introduced, allowing accurate observation of SAM lattice parameters, and, of the many possible atomic structures modeled, only the lowest-energy structure obtained was found to predict the observed lattice parameters and image topography. Hydrogen atoms are shown to provide the conduit for the tunneling current through the alkyl chains.

We demonstrate that systematic errors can be reduced and physical insight gained through investigation of the dependence of free energies for meso-tetraalkylporphyrin self-assembled monolayers (SAMs) polymorphism on the alkyl chain length m. These SAMs form on highly-ordered pyrolytic graphite (HOPG) from organic solution, displaying manifold densities and atomic structures. SAMs with m= 11-19 are investigated experimentally while those with m= 6-28 are simulated using density-functional theory (DFT). It is shown that for m= 15 or more the alkyl chains "crystallize" to dominate SAM structure. Meso-tetraalkylporphyrin SAMs of length less than 11 have never been observed, a presumed effect of inadequate surface attraction. Instead, we show that free energies of SAM formation actually enhance as the chain length decreases. The inability to image regular SAMs stems from the appearance of many polymorphic forms of similar free energy, preventing SAM ordering. We also demonstrate a significant odd/even effect in SAM structure arising from packing anomalies. Comparison of the chain-length dependence of formation free energies allows the critical dispersion interactions between molecules, solvent, and substrate to be directly examined. Interpretation of the STM data combined with measured enthalpies indicates that Grimme's "D3" explicit-dispersion correction and the implicit solvent correction of Floris, Tomasi and Pascual Ahuir are both quantitatively accurate and very well balanced to each other.

The syntheses of a series of 1‐phenyl‐5‐phosphino 1,2,3‐triazoles are disclosed, within which, the phosphorus atom (at the 5‐position of a triazole) is appended by one, two or three triazole motifs, and the valency of the phosphorus(III) atom is completed by two, one or zero ancillary (phenyl or cyclohexyl) groups respectively. This series of phosphines was compared with tricyclohexylphosphine and triphenylphosphine to study the effect of increasing the number of triazoles appended to the central phosphorus atom from zero to three triazoles. Gold(I) chloride complexes of the synthesised ligands were prepared and analysed by techniques including single‐crystal X‐ray diffraction structure determination. Gold(I) complexes were also prepared from 1‐(2,6‐dimethoxy)‐phenyl‐5‐dicyclohexyl‐phosphino 1,2,3‐triazole and 1‐(2,6‐dimethoxy)‐phenyl‐5‐diphenyl‐phosphino 1,2,3‐triazole ligands. The crystal structures thus obtained were examined using the SambVca (2.0) web tool and percentage buried volumes determined. The effectiveness of these gold(I) chloride complexes to serve as precatalysts for alkyne hydration were assessed. Furthermore, the regioselectivity of hydration of but‐1‐yne‐1,4‐diyldibenzene was probed.

Self-assembled microrods {based on 5-nitro-10,15,20-trialkylporphyrins [(C n H 2n+1 ) 3 -NO 2 P]} and microplates {based on 5,10,15,20-tetraheptylporphyrin [(C 7 H 15 ) 4 -P]} are fabricated and characterised using optical microscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). The length of the alkyl chains and the deposition surface are found to influence the optical properties and microrod self-assembly. When the deposition surface is silica (a-quartz), 5-nitrotrialkylporphyrins, (C 5 H 11 ) 3 -NO 2 P, (C 7 H 15 ) 3 -NO 2 P and (C 11 H 23 ) 3 -NO 2 P all form microrods of 0.7-0.8 micron diameter; the average length of the microrods varies from 170 microns for (C 5 H 11 ) 3 -NO 2 P to about 11 microns for (C 7 H 15 ) 3 -NO 2 P and (C 11 H 23 ) 3 -NO 2 P, whereas (C 19 H 39 ) 3 -NO 2 P with much longer alkyl chains only gives powders. Controlling the precipitation is crucial in preventing the disordered aggregation of assembled layers observed in the bulk. Very interestingly, the microrods formed from (C 7 H 15 ) 3 -NO 2 P show marked iridescent character. When (C 7 H 15 ) 3 -NO 2 P is deposited on silicon, however, longer curved microrods which do not show iridescence are produced. Single crystal X-ray crystallography of (C 7 H 15 ) 3 -NO 2 P reveals the packing of the bulk material which explains the packing topology of the layers observed by AFM but not the iridescence. The observed structural colour of the (C 7 H 15 ) 3 -NO 2 P microrods is explained by staggering of the layers to produce a corrugated surface with a period of 125 nm, as measured by AFM.