Distortion and bonding strength of phthalocyanine molecules adsorbed on topological defects in graphene

Lanthanide bisphthalocyanine single-molecule magnets: A DFT survey of their geometries and electronic properties from lanthanum to lutetium

“…There were two reasons for this preference; first, several other theoretical studies of LnPc 2 complexes employed this functional [27,29,31,34,35]. Second, the present work represents an important step in our ongoing systematic study of the noncovalent interactions of phthalocyanines with different carbon nanostructures such as fullerenes [42][43][44][45], carbon nanotubes [46][47][48][49][50][51][52] and graphene [53]: for the sake of a valid comparison with our previous results, it is crucial to continue to use the same theoretical approach. Furthermore, when in the future we will perform similar computations where we combine lanthanide bisphthalocyanines with carbon nanostructures, we have to use such a cost-efficient and at the same time reliable combination as PBE-D.…”

Adsorption of lanthanide double-decker phthalocyanines on single-walled carbon nanotubes: structural changes and electronic properties as studied by density functional theory

“…Structural comparison of isolated phthalocyanines and those adsorbed on the surface of nanotubes [ 22 – 24 ] and other carbon nanomaterials such as the endohedral fullerene Sc 3 N@C 80 [ 37 ] and graphene with defects [ 25 , 26 ] revealed an important typical feature of these macrocycles, namely, a strong bending distortion of Pc ligands upon interaction, increasing in such a way the area of Pc contact with the latter: in particular, this was observed for free-base H 2 Pc, its 3d transition metal(II) complexes, as well as yttrium double-decker phthalocyanine interacting with SWCNTs models. This bending due to non-parallel π-π interactions between the two extended π systems occurs to a variable degree, depending on the central atom, the diameter and chirality of the carbon nanotubes [ 22 – 24 , 44 , 45 ].…”

“…The geometry optimizations and calculations of energies and electronic characteristics of LnPc 2 +SWCNTs hybrids were performed by using the numerical-based DFT module DMol 3 available as part of the Materials Studio 8.0 software from Accelrys, Inc. [ 31 – 34 ]. The general gradient approximation (GGA) functional by Perdew-Burke-Ernzerhof (PBE) [ 35 ] in combination with a long-range dispersion correction by Grimme [ 36 ] (PBE-D2) was the computational technique of choice, because dispersion interactions need to be taken into account, when noncovalently bonded molecular systems are analyzed such as the complexes of tetraazamacrocyclic (including porphyrins and Pcs) and many other compounds with fullerene [ 27 , 37 ], graphene [ 25 , 26 ] and carbon nanotube models [ 22 – 24 , 38 , 39 ]. Moreover, there are already theoretical studies involving specifically MPc 2 complexes that employed this functional [ 9 , 40 – 43 ].…”

“…Other aspects we addressed were the changes in electronic characteristics upon the YPc 2 adsorption, the effect of nanotube chirality and of the size of double numerical basis sets available in DMol 3 module (DN, DND, and DNP). Compared to MPc and YPc 2 hybrids with nanotubes [ 22 – 24 ], graphene [ 25 , 26 ], and fullerenes [ 27 , 28 ], the same computational task for systems including lanthanide derivatives is computationally much more demanding. As in the case of YPc 2 , a second large-size C 32 H 16 N 8 ligand is present, which, when combined with the computational challenge of the 4f electrons from Ce to Lu, and thus with the appearance of a series of highly degenerate states, dramatically complicates the self-consistence field (SCF) convergence.…”

Strong Bending Distortion of a Supercoronene Graphene Model upon Adsorption of Lanthanide Atoms

“…However, while being an appropriate choice for the analysis of conductivity and related crucial electronic characteristics, periodic models offer a very limited opportunity for graphene structure modification. In particular, while it is possible to introduce single and double vacancies, doping heteroatoms, and Stone–Wales defects, which can be found within the graphene sheet, periodic models cannot account for atoms (for example, H) and/or functional groups (for example, −OH, O, and −COOH) existing at the edges of real-world finite nanostructures. , In addition, even in the case of all-C structures there are some for which periodic models simply cannot be built, for example, those having pentagonal symmetry. − …”