A suitable technology for the preparation of graphene based on versatile wet chemistry is presented for the first time. The protocol allows the wet chemical synthesis of graphene from a new form of graphene oxide that consists of an intact hexagonal σ-framework of C-atoms. Thus, it can be easily reduced to graphene that is no longer dominated by defects.

We address the dynamic behavior and the surface chemical bond of 2H-tetraphenylporphyrin (2HTPP) on Cu(111) around room temperature by variable-temperature scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum. Between 280 and 345 K, the molecules predominantly display unidirectional diffusion along one of the three densely packed substrate AE110ae directions, which is attributed to a high site selectivity of the adsorbateÀsubstrate bond. Above 305 K, the diffusion direction is found to change occasionally by (120°. The activation barriers for the unidirectional diffusion and for rotation of the diffusion direction are determined to 0.71 ( 0.08 and 1.28 ( 0.12 eV, respectively. XPS shows that the iminic nitrogen atoms of 2HTPP interact strongly with the Cu surface. It is postulated that the local bonding situation is similar as in the initial complex (sitting-atop complex), which has previously been observed during the surface-confined in situ metalation of porphyrins.

The self-assembly of molecular building blocks on flat surfaces opens up the perspective to engineer molecular architectures with tailored functionalities. [1,2] Porphyrins appear as ideal candidates for such building blocks: they combine a rigid-structural theme, that is, the macrocycle, which often triggers long-range order, and a central metal atom as active site; this determines the intrinsic functionality. [3] Indeed, the generation of multicomponent porphyrinoid adlayers has successfully been realized and characterized by scanning tunneling microscopy (STM) on different surfaces in ultrahigh vacuum (UHV) [4][5][6] and in solution. [7] The key for the fabrication of tailored supramolecular networks is detailed understanding of the adsorption behavior of the involved molecules, which is determined by the interplay of molecule-substrate and molecule-molecule interactions. (111) (U = À1.94 V, I = 27 pA). e) STM image of an individual 2HTPP with the corresponding, scaled, space-filling model (U = À1.49 V, I = 30 pA). A closed-packed Cu atomic row is indicated, highlighting the coordinative bond between the iminic nitrogens of 2HTPP and the copper substrate atoms. f) STM image of a single CoTPP with the corresponding, scaled, space-filling model (U = À1.48 V, I = 27 pA).

Using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM), the coverage-dependent self-metalation of 2H-tetraphenylporphyrin (2HTPP) with Cu on Cu(111) at 400 K has been studied. At low coverages the porphyrin molecules are adsorbed as isolated molecules, and the rate of metalation is slow. As the coverage is increased beyond ∼0.36 molecules/nm2, a supramolecular checkerboard structure is formed, with every second molecule slightly elevated above the surface. The appearance of this checkerboard structure coincides with a dramatic increase in the rate of metalation. This enhancement is attributed to a smaller activation barrier for the elevated molecules, which have an internal conformation similar to that of the free molecule, whereas the less reactive molecules in direct contact with the surface are strongly distorted.

Using temperature-programmed desorption, supported by X-ray photoelectron spectroscopy and scanning tunneling microscopy, a comprehensive overview of the main reactions of 5,10,15,20-tetraphenyl-21H,23H-porphyrin (2HTPP) on Cu(111) as a function of coverage and temperature is obtained. Three reactions were identified: metalation with Cu substrate atoms, stepwise partial dehydrogenation, and finally complete dehydrogenation. At low coverage the reactions are independent of coverage, but at higher coverage metalation becomes faster and partial dehydrogenation slower. This behavior is explained by a weaker interaction between the iminic nitrogen atoms and the Cu(111) surface in the high-coverage checkerboard structure, leading to faster metalation, and the stabilizing effect of T-type interactions in the CuTPP islands formed at high coverage after metalation, leading to slower dehydrogenation. Based on the amount of hydrogen released and the appearance in STM, a structure of the partially dehydrogenated molecule is suggested.