Electronic and magnetic properties regulation of finite to infinite half sandwich organo-transition-metal-complexes functionalized graphene

Abstract

Total band gaps (Δt) and band gaps of free “graphene”, ignoring impurity bands of TMnOLs (Δg).

Theoretical exploration on the electronic and magnetic properties of (FeCp)n– (n = 1, 2) ligand-functionalized graphene

“…where E[$] represents the total energy of (FeCp) n @SLGs, the Cp ligands, Fe atom and pristine graphene, and n is the number of FeCp ligands. Our results show that the binding energies of all the studied FeCp@G 33 s are positive and range from 256 kJ mol À1 to 285.9 kJ mol À1 , which is much larger than that of the FeBz@G isomer (211 kJ mol À1 ), 28 where such large binding energies show that the chemical attachment dominates the FeCp ligands and graphene interaction. As shown in the charge density difference plots (CDDs) ( Fig.…”

“…2e-j), leading to a more ionic bonding character of Fe-Cp and more covalent bonding characters of Fe-graphene. Different from the FeBz@G isomer, 28 the D Fe-Cp of FeCp@G 33 -S is a bit larger, $1.76Å, whereas a different case is veried for that of D Fe-G , $1.64Å. Compared with that of FeCp@G 33 -S, the D Fe-G of (FeCp) 2 @G 33 -D 1 is much larger, $1.69Å, whereas for the (FeCp) 2 @G 33 -D 2 and (FeCp) 2 @G 33 -D 3 isomers, the D Fe-G s are reduced sharply to 1.60Å (see Table 1).…”

“…In (FeCp) n @G 33 s, the states around the Fermi energy level are mainly contributed by the d electrons of the Fe atom, which indicates that the magnetic moments of the studied systems are mainly contributed by the unpaired d electrons of the Fe atom. Corresponding to FeBz@SLG (2.0 m B ), 26,28 the magnetic moment of FeCp@G 33 -S is largely reduced. As shown in Fig.…”

“…Alternatively, chemical/physical adsorption has been proven to be a simple and effective solution to tune the electronic properties of graphene, [21][22][23][24][25][26][27][28][29][30] in which the approach of loading half organotransition metal (TM) ligands (OTMLs) on graphene substrates has been theoretically explored. [25][26][27][28][29] The adsorption of OTMLs on graphene has two signicant advantages: (i) compared with two-end closed organometallic sandwich clusters, [31][32][33] the bonding between half TM n OLs and graphene is stronger due to coordinate d-p bonding. For example, the chemical attachment of a C 60 fullerene on graphene is not energetically feasible, 24 whereas connecting graphene and C 60 using a bridging Cr atom can largely enhance the binding energy; 25 (ii) with single TM atom adsorbed graphene, e.g.…”

“…27 In our previous studies, a density related band gap was observed for TMBz-functionalized graphene. 28,29 Compared with hexagonal hydrocarbon organic ligands (e.g. benzene), the bonding of TM atoms with the cyclopentadienyl (Cp ¼ C 5 H 5 ) ligand was found to display different bonding mechanisms due to the fact that it has one less valence electron.…”