Self-assembled nanostructures of 2,5-pyrazine dicarboxylic acid (PDA) on a model noble metal surface, Cu(100), are studied to probe intermolecular interactions in 1D and 2D organic nanostructures. All work has been done under ultra-high vacuum conditions, with analysis done using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). The PDA molecule is similar in structure to terephthalic acid (TPA), which has been extensively studied, but contains two nitrogen atoms in the ring. After deposition on a room temperature surface, the PDA molecules form islands with a square structure. This square structure has similar measurements to the square structure formed by TPA, but the growth direction is different from the growth direction of the TPA islands,1 indicating a difference in surface adsorption between TPA2 and PDA. After annealing at 90 oC, PDA forms 2D islands with a rectangular structure and 1D chains of molecules, with some islands with the square structure remaining. The PDA molecular chains grow in the same directions as the TPA molecular islands and have similar molecular spacing. They differ from TPA because of the prochiral nature of PDA causing the PDA molecules to self-select into homochiral chains. The 1D chains are likely caused by repulsive interactions between the lone pairs of the ring nitrogen atoms and the electronegative carboxylate oxygen atoms, inhibiting growth in one direction. XPS after annealing is not significantly different from spectra before annealing, indicating no decomposition of the adsorbed PDA. Studies of transition metal complexation with PDA are ongoing. 1.         Lingenfelder, M. A.; Spillmann, H.; Dmitriev, A.; Stepanow, S.; Lin, N.; Barth, J. V.; Kern, K., Chem.� Eur. J. 2004,  10 (8), 1913-1919. DOI: 10.1002/chem.2003055892.         Ge, Y.; Adler, H.; Theertham, A.; Kesmodel, L. L.; Tait, S. L., Langmuir 2010,  26 (21), 16325-16329. DOI: 10.1021/la101582k

1D and 2D self-assembled nanostructures of 2,5-pyrazine dicarboxylic acid on the Cu(100) surface

246th National Meeting (2013)

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