M. E. Bedrina

Highly symmetrical phthalocyanines and perfluorophthalocyanines: The quantum-chemical study

By the quantum-chemical method (U)B3LYP/6-31G(d5,p) are determined point symmetry group (D4h) and equilibrium structure of phthalocyanine (PcH2), phthalocyaninates PcBe, PcMg, PcCo, PcNi, PcCu, PcZn, perfluorophthalocyaninates FPcNi, FPcCu, FPcZn, cations Pc+Mt, FPc+Mt and anion PcCo−. In the approximation (U)B3LYP/6-311++G(3d5f7,p)//6-31G(d5,p) is achieved the satisfactory accuracy of the calculation of ionization potentials of the studied molecules. Effect of nuclear relaxation at the ionization is 0.07±0.06 eV; correction for “zero” vibrations does not exceed 0.01 eV. Perfluorination increases ionization potentials by 0.7–0.8 eV.

Computer simulation of the structure of large molecules: IV. 2D polybuckminsterfullerenes and their boraza analogs with bisingle nitrogen-boron bonds

The equilibrium structure of the dimer (C60)2, clusters (C60)9, and (C60)7 simulating the poly-C60 (VIII) and poly-C60 (XII), as well as their boraza analogs with bisingle nitrogen-boron bonds was determined by the quantum-chemical methods B3LYP/6-31G and PBE0/6-31G. The boraza analogs are characterized by the positive values of calculated (B3LYP/PBE0) energies of the interpolyhedral bonds: 10/20, 35/74, and 54/109 kcal mol−1 respectively per a pair of monomers. The PBE0 method predicts shorter bond than B3LYP, and, in accordance with calorimetric data, positive bonding energy of the polyhedra in (C60)n.

A quantum chemical study of the Fe@C 60 endocomplex

At the DFT (U)PBE0/cc-pVDZ level the structural parameters of a hypothetical Fe@C60 endocomplex are determined. The (A1//C3v)–Fe@C60 state characterized by the electron spin square of 3.07 au, the free valence of 4.15, the dipole moment of 1.15 D, and the 172 pm Fe nuclear shift relative to the center of inertia of С60 corresponds to the energy minimum. The Stone–Wales rearrangement in the quasi-triplet state increases the endocomplex energy by 1.56 eV and by 0.79 eV in the quasi-quintet state.

Quantum-chemical study of ytterbium fluorides and of complex F2YbF2CeF2

The structural parameters of the (2Σ+//C∞v)-YbF, (1A1//C2v)-YbF2, (2A2′//D3h)-YbF3, (1Ag//D2h)-YbF2Yb, (1Ag//C2h)-FYbF2YbF, (1A1//C2v)-FYbF2YbF, (1A1//C2v)-YbF2YbF2, (3B3u//D2h)-F2YbF2YbF2, (2A′//Cs)-FYbF2YbF2, and (3B2//С2v)-F2YbF2CeF2 molecules have been determined. Disproportionation of ytterbium monofluoride (2YbF → YbF2 + Yb + 0.46 eV) is less exothermic than dimerization (2YbF → YbF2Yb + 2.10 eV). The bond energy of the ytterbium difluoride molecules in the trans dimer (2.93 eV) exceeds those in the cis dimer (2.86 eV) and the coaxial dimer (1.66 eV). Ytterbium trifluoride dimerizes exothermically (2.95 eV) without spin pairing. The dipole and quadrupole moments of the molecules as well as the charges and spin populations of the atoms and the valence electron configurations of the lanthanides have been calculated.

Quantum-chemical study of lutetium, ytterbium, and gadolinium phthalocyaninates PcLnCl

Structural parameters and IR spectra of the (1A1//C4v)-PcLuCl, (2B2//C4v)-PcYbCl, and (8A2//C4v)-PcGdCl molecules, (2A2//C4v)-Pc+LuCl, (3B1//C4v)-Pc+YbCl, and (9A1//C4v)-Pc+GdCl cations, (1Ag//D2h)-PcLuCl2LuPc dimer, and PcLuCl···PcLuCl coaxial molecular pair have been simulated using the DFT (U) PBE0/SDD method. The PcLnCl (Ln = Lu, Yb, Gd) molecules have exhibited the equilibrium Ln–N bond length of 222, 223, and 230 pm, the Ln–Cl bond length of 245, 246, and 253 pm, the dipole moment of 4.73, 4.57, and 4.84 D directed from Cl to Ln, and ionization potential of 6.6 eV. β-Decay (1A1//C4v)-Pc177LuCl → (1A1//C4v)-(Pc177mHfCl)+ occurs with no significant change of the charge on the metal atom.

Quantum-chemical study of lutetium and ytterbium bis- and tetrakis(phthalocyaninates)

DFT calculations with B3LYP and PBE0 functionals have been carried out to determine the structural parameters, vibrational frequencies, and quadrupole moments of double-decker heavy lanthanide phthalocyaninates Pc2Lu, (Pc2Lu)+, (Pc2Lu)–, Pc2Yb, (Pc2Yb)+, and (Pc2Yb)–. Free valence of the Pc moiety [0.5 in Pc2Lu and Pc2Yb; 1.0 in (Pc2Lu)+ and (Pc2Yb)+] is delocalized in small fractions over the carbon atoms. The Pc2Lu и Pc2Yb molecules have a high electron affinity (3.2 eV) and a low ionization potential (6.1–6.3 eV). Calculations predict formation of quadruple-decker supercomplex Yb(Pc2Lu)2 from two Pc2Lu molecules and an Yb atom via an exothermic process. The equilibrium structure of the molecules and ions can be characterized by D4d point symmetry group.

A Quantum Chemical Study of C60Cl30, C60(OH)30 Molecules and Fe@C60(OH)30 Endocomplex

Abstract(U)PBE0/cc-pVDZ method is used to study the structure of C60Cl30, C60(OH)30 molecules and Fe@C60(OH)30 endocomplex. The triplet state of the endocomplex is shown to be the lowest in energy among its four states corresponding to different spin multiplicities and positions of Fe nucleus within the fullerene cavity. This state is characterized by bonding between the iron atom and one of two benzenoid cycles of the carbon cage, six internuclear Fe–C distances (208 pm), and 1s22s22p63s23p63d7.24s0.14p0.3 electron configuration of iron with spin population of 2.36.

Simulation of metal ion coordination sphere in crystals with fluorite structure

Using quantum-chemical methods, it has been found that the structure of fluorite coincides with the symmetry and coordination number of central calcium atom in the (Oh)-Ca7F14 cluster. The Ca–F and F–F interatomic distances in the cluster are 3–4% shorter than in the crystal. The symmetry of the (Oh)–(ScCa6F14)+ cluster mimicking the cationic defect after the β-decay of 45Ca does not correspond to the energy minimum. The increase in the cation charge from 1.79 to 2.80 a. u. reduces the radius of the first coordination sphere by 0.14 Å. For ytterbium dihalides, the bond lengths Yb–F 2.344, Yb–Cl 2.897 Å and the cation charges 1.81, 1.64 a. u., respectively, have been found.

A quantum chemical study of gallium(III) (μ-oxo)bis[phthalocyaninate] and gallium(III) (μ-oxo)bis[perfluorophthalocyaninate] molecules

By the DFT (U)PBE0 method the structural parameters of molecules, cations, dications, and anions of gallium(III) (μ-oxo)bis[phthalocyaninate], gallium(III) (μ-oxo)bis[perfluorophthalocyaninate], and heteroleptic bis-phthalocyaninate FPcGaOGaPc are determined. The ∠GaOGa bond angle and the Ga⋯Ga internuclear distance depend non-monotonically on the charge. The ionization potential of the (PcGa)2O molecule of 5.71 eV, the second electron detachment energy of 7.94 eV, and the electron affinity of 2.14 eV increase to 6.14 eV, 8.37 eV, and 2.72 eV after the perfluorination of one Pc moiety and to 6.60 eV, 8.70 eV, and 3.13 eV respectively after complete fluorination.

Quantum chemical calculation of spectroscopic and photoelectronic characteristics of [n]staffanes

Structural parameters, IR spectra, 1H and 13C NMR spectra, quadrupole moments, and dipole polarizabilities of seven [n]staffanes with a distance between the terminal carbon atoms of up to 22.0 Å have been determined by DFT quantum chemical calculations at the PBE0/cc-pVTZ level of theory.