Bead-like structures and self-assembled monolayers from 2,6-dipyrazolylpyridines and their iron(ii) complexesElectronic supplementary information (ESI) available: Synthetic procedures and characterisation data for L2, L3 and salts of [Fe(L3)2]2+; experimental details, figures and tables for crystal structures of [Fe(L3)2]X2 (X− = BF4−, ClO4− and CF3SO3−); additional STM images, XPS and ellipsometry data. CCDC 1058749-1058751. For ESI and crystallographic data in CIF or other electronic format se

• Main Authors: Pukenas, Laurynas, Benn, Florence, Lovell, Edmund, Santoro, Amedeo, Kershaw Cook, Laurence J, Halcrow, Malcolm A, Evans, Stephen D
• Format: Article
• Language: English
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c5tc01233c

Drop-casting acetone solutions of [Fe(bpp) 2 ][BF 4 ] 2 (bpp = 2,6-di[pyrazol-1-yl]pyridine) onto a HOPG surface affords unusual chain-of-beads nanostructures. The beads in each chain are similar in size, with diameters in the range of 2-6 nm and heights of up to 10 Å, which is consistent with them containing between 10-50 molecules of the compound. The beads can be classified into two types, which exhibit different conduction regimes by current-imaging tunnelling spectroscopy (CITS) which appear to correlate with their positions in the chains, and may correspond to molecules containing high-spin and low-spin iron centres. Similarly drop-cast films of the complex on a gold surface contain the intact [Fe(bpp) 2 ][BF 4 ] 2 compound by XPS. 4-Mercapto-2,6-di[pyrazol-1-yl]pyridine undergoes substantial decomposition when deposited on gold, forming elemental sulfur, but 4-( N -thiomorpholinyl)-2,6-di[pyrazol-1-yl]pyridine successfully forms SAMs on a gold surface by XPS and ellipsometry. Drop-casting [Fe(bpp) 2 ][BF 4 ] 2 (bpp = 2,6-di[pyrazol-1-yl]pyridine) onto HOPG affords chain-of-beads nanostructures. SAMs of bpp derivatives with sulfur-containing tethers are also described.