| 1. |
- Simonov, Konstantin A., et al.
(författare)
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From Graphene Nanoribbons on Cu(111) to Nanographene on Cu(110) : Critical Role of Substrate Structure in the Bottom-Up Fabrication Strategy
- 2015
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 9:9, s. 8997-9011
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Tidskriftsartikel (refereegranskat)abstract
- Bottom-up strategies can be effectively implemented for the fabrication of atomically precise graphene nanoribbons. Recently, using 10,10'-dibromo-9,9'-bianthracene (DBBA) as a molecular precursor to grow armchair nanoribbons on Au(111) and Cu(111), we have shown that substrate activity considerably affects the dynamics of ribbon formation, nonetheless without significant modifications in the growth mechanism. In this paper we compare the on-surface reaction pathways for DBBA molecules on Cu(111) and Cu(110). Evolution of both systems has been studied via a combination of core-level X-ray spectroscopies, scanning tunneling microscopy, and theoretical calculations. Experimental and theoretical results reveal a significant increase in reactivity for the open and anisotropic Cu(110) surface in comparison with the close-packed Cu(111). This increased reactivity results in a predominance of the molecular substrate interaction over the intermolecular one, which has a critical impact on the transformations of DBBA on Cu(110). Unlike DBBA on Cu(111), the Ullmann coupling cannot be realized for DBBA/Cu(110) and the growth of nanoribbons via this mechanism is blocked. Instead, annealing of DBBA on Cu(110) at 250 degrees C results in the formation of a new structure: quasi-zero-dimensional flat nanographenes. Each nanographene unit has dehydrogenated zigzag edges bonded to the underlying Cu rows and oriented with the hydrogen-terminated armchair edge parallel to the [1-10] direction. Strong bonding of nanographene to the substrate manifests itself in a high adsorption energy of -12.7 eV and significant charge transfer of 3.46e from the copper surface. Nanographene units coordinated with bromine adatoms are able to arrange in highly regular arrays potentially suitable for nanotemplating.
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| 2. |
- Svirskiy, Gleb I., et al.
(författare)
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Electronic structure of the [Ni(Salen)] complex studied by core-level spectroscopies
- 2021
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 23:18, s. 11015-11027
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Tidskriftsartikel (refereegranskat)abstract
- The nature and structure of occupied and empty valence electronic states (molecular orbitals, MOs) of the [Ni(Salen)] molecular complex (NiO2N2C16H14) have been studied by X-ray photoemission and absorption spectroscopy combined with density functional theory (DFT) calculations. As a result, the composition of the high-lying occupied and low-lying unoccupied electronic states has been identified. In particular, the highest occupied molecular orbital (HOMO) of the complex is found to be predominantly located on the phenyl rings of the salen ligand, while the states associated with the occupied Ni 3d-derived molecular orbitals (MOs) are at higher binding energies. The lowest unoccupied molecular orbital (LUMO) is also located on the salen ligand and is formed by the 2pπ orbitals of carbon atoms in phenyl groups of the salen macrocycle. The unoccupied MOs above the LUMO reflect σ- and π-bonding between Ni and its nearest neighbours. All valence states have highly mixed character. The specific nature of the unoccupied Ni 3d-derived σ-MO is a consequence of donor-acceptor chemical bonding in [Ni(Salen)]. This journal is
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| 3. |
- Andreyev, Oleg A., et al.
(författare)
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Privatization of municipal property in Murmansk
- 1995
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Ingår i: Polar Geography. - : Taylor & Francis Group. - 1088-937X .- 1939-0513. ; 19:2, s. 88-106
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results of a pilot study of privatization of municipal property in the Russian North based on data from the Murmansk city government. After a general overview of the process in Russia and Murmansk city, the paper outlines a number of positive and negative aspects of the privatization of city-owned enterprises on the basis of interviews conducted with the management of the newly privatized enterprises.
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