Theoretical Investigation of the Electronic Properties of Three Vanadium Phthalocyaninato (Pc) Based Complexes: PcV, PcVO, and PcVI

Abstract

The electronic properties of three vanadium phthalocyaninato (Pc) based complexes (PcV, PcVO, and PcVI; I-III, respectively) were theoretically investigated and corresponding L-edge XAS spectra modeled. Ground state (GS) DFT outcomes indicated that II is more stable than III by 141 kcal/mol; moreover, the Ziegler transition state method allowed us to estimate the PcV-X bond dissociation energy and to quantify σ/π contributions to the V-X interaction. As such, the Nalewajski-Mrozek V-X and V-N bond multiplicity indexes (V-O/V-I = 2.48/1.22; V-N = 0.64, 0.51, and 0.58 in I-III, respectively) state that the V-X bond strength and nature affect the V-N interaction. The coordination of X to V in the I → II/I → III reactions implies the transfer of two/one electrons from I to X. In both cases, the oxidation involves only the V ion; moreover, V 3d based orbitals from which electrons are transferred were identified. Literature L-edge XAS data were modeled by exploiting the DFT/ROCIS method. The same protocol was adopted to predict L-edge XAS spectra. Theoretical results indicated that, along the whole series, spectral features lying at the lowest excitation energies (EEs) are mostly generated by states having the same GS spin multiplicity and involve 2p → SOMO (single occupied molecular orbital) single electronic excitations. XAS features at higher EEs include only states with the same GS spin multiplicity in I, while states with both ΔS = 0 and ΔS = +1 (S = total spin quantum number) are present in II and III with significant, in some cases prevailing, contributions from metal to ligand charge transfer (MLCT) excitations. Beyond the role played by MLCT transitions in determining XAS patterns, it is noteworthy that they involve only Pc-based empty orbitals with no participation of the X-based virtual levels.

Stability, electronic structure, and magnetic moment of vanadium phthalocyanine grafted to the Au(1 1 1) surface

“…All these quantities are shown in Table 1. The calculated distance between V and N atoms d(V-N) equals to 1.99 Å and compares very well with previous calculations predicting the distance d(V-N) to be equal to 1.99 Å [34,23]. The total magnetic moment of the whole molecule M is equal to 3.00 𝜇 𝐵 and compares fairly well with magnetic moment computed for V-Pc polymer [34].…”

“…PcV, PcVO, and PcVI [23], where the XAS spectra were modeled exploring the DFT/ROCIS method. The electronic states and magnetic interactions were investigated experimentally for vanadyl phthalocyanine (VO-Pc) [24] on Si(111)-(7x7) reconstructed surface [25], on Ag(111) surface [25], and also on ferromagnetic Fe, Co, and Ni films [26].…”

Ferrous to Ferric Transition in Fe‐Phthalocyanine Driven by NO2 Exposure

“…The adoption of the molecular cluster approach to model a periodic system implies the saturation of the oxygen dangling bonds with hydrogen/pseudo‐hydrogen atoms [49] . Therefore, the coordinated system resulting from low NO 2 dosing has been modelled by considering the free molecular complex I (see its optimized structure in Figure 4) characterized by the presence of a single oxygen atom of water molecule placed at 1.8 Å from the Fe II ion [50] . The Fe L‐edge NEXAFS modelling has been carried out for both s ‐ and p ‐polarized excitation.…”

“…[49] Therefore, the coordinated system resulting from low NO 2 dosing has been modelled by considering the free molecular complex I (see its optimized structure in Figure 4) characterized by the presence of as ingle oxygen atom of water molecule placed at 1.8 from the Fe II ion. [50] The Fe Ledge NEXAFS modelling has been carriedo ut for both s-a nd p-polarized excitation.T he final good agreement between theory and experiment is ac lear indication of the adopted model feasibility.…”

Tris-{Hydridotris(1-pyrazolyl)borato}lanthanide Complexes: Synthesis, Spectroscopy, Crystal Structure and Bonding Properties

“…The bonding properties of the complexes were analyzed using the extended transition state (ETS) energy decomposition [15,18] and the quantum theory of atoms in molecules (QTAIM) models [16]. These theoretical models have been successfully applied in numerous studies of bonding trends in organometallic complexes [14,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34].…”