Theoretical study of M+ RG2: (M+= Ca, Sr, Ba and Ra; RG= He–Rn)

Ab initio calculations were employed to investigate M+ RG2 species, where M+ = Ca, Sr, Ba and Ra and RG= He–Rn. Geometries have been optimized, and cuts through the potential energy surfaces containing each global minimum have been calculated at the MP2 level of theory, employing triple-ζ quality basis sets. The interaction energies for these complexes were calculated employing the RCCSD(T) level of theory with quadruple-ζ quality basis sets. Trends in binding energies, De, equilibrium bond lengths, Re, and bond angles are discussed and rationalized by analyzing the electronic density. Mulliken, natural population, and atoms-in-molecules (AIM) population analyses are presented. It is found that some of these complexes involving the heavier Group 2 metals are bent whereas others are linear, deviating from observations for the corresponding Be and Mg metal-containing complexes, which have all previously been found to be bent. The results are discussed in terms of orbital hybridization and the different types of interaction present in these species

Mechanistic Studies of Ethylene Hydrophenylation Catalyzed by Bipyridyl Pt(II) Complexes

This article discusses mechanistic studies of ethylene hydrophenylation catalyzed by bipyridyl Pt(II) complexes

Calculations of the Relative Energies of the 2

Article on a proposed experimental test of the prediction of a triplet ground state for (CO)4

Naphthalenyl, anthracenyl, tetracenyl, and pentacenyl radicals and their anions

Electronic structure theory has been applied to the naphthalene-, anthracene-, tetracene-, and pentacene-based radicals and their anions. Five different density functional methods were used to predict adiabatic electron affinities for these radicals. A consistent trend was found, suggesting that the electron affinity at a site of hydrogen removal is primarily dependent upon steric effects for polycyclic aromatic hydrocarbons. The results for the 1-naphthalenyl and 2-naphthalenyl radicals were compared to experiment, and it was found that B3LYP appears to be the most reliable functional for this type of system. For the larger systems the predicted site specific adiabatic electron affinities of the radicals are 1.51 eV (1-anthracenyl), 1.46 eV (2-anthracenyl), and 1.68 eV (9-anthracenyl); 1.61 eV (1-tetracenyl), 1.56 eV (2-tetracenyl), and 1.82 eV (12-tetracenyl); and 1.93 eV (14-pentacenyl), 2.01 eV (13-pentacenyl), 1.68 eV (1-pentacenyl), and 1.63 eV (2-pentacenyl). These electron affinities are 0.5-1.5 eV higher than those for the analogous closed-shell singlet polycyclic aromatic hydrocarbons (PAHs); i.e., EA(anthracene) = 0.53 eV. The global minimum for each radical does not have the same hydrogen removed as the global minimum for the analogous anion. With this in mind, the global (or most preferred site) AEAs are 1.37 eV (naphthalenyl), 1.64 eV (anthracenyl), 1.81 eV (tetracenyl), and 1.97 eV (pentacenyl)

The structure of ScC2 (X̃2A1): A combined Fourier transform microwave/millimeter-wave spectroscopic and computational study

Pure rotational spectra of Sc13C2 (X̃X̃2A1) and Sc12C13C (X̃X̃2A′) have been measured using Fourier transform microwave/millimeter-wave methods. These molecules were synthesized in a DC discharge from the reaction of scandium vapor, produced via laser ablation, with 13CH4 or 13CH4/12CH4, diluted in argon. The NKa,Kc = 10,1 → 00,0, 20,2 → 10,1, 30,3 → 20,2, and 40,4 → 30,3 transitions in the frequency range of 14 GHz–61 GHz were observed for both species, each exhibiting hyperfine splittings due to the nuclear spins of 13C (I = 1/2) and/or Sc (I = 7/2). These data have been analyzed with an asymmetric top Hamiltonian, and rotational, spin-rotation, and hyperfine parameters have been determined for Sc13C2 and Sc12C13C. In addition, a quartic force field was calculated for ScC2 and its isotopologues using a highly accurate coupled cluster-based composite method, incorporating complete basis set extrapolation, scalar relativistic corrections, outer core and inner core electron correlation, and higher-order valence correlation effects. The agreement between experimental and computed rotational constants, including the effective constant (B + C), is ∼0.5% for all three isotopologues. This remarkable agreement suggests promise in predicting rotational spectra of new transition metal-carbon bearing molecules. In combination with previous work on Sc12C2, an accurate structure for ScC2 has been established using combined experimental (B, C) and theoretical (A) rotational constants. The radical is cyclic (or T-shaped) with r(Sc–C) = 2.048(2) Å, r(C–C) = 1.272(2) Å, and ∠(C–Sc–C) = 36.2(1)°. The experimental and theoretical results also suggest that ScC2 contains a C2− moiety and is largely ionic.12 month embargo; published online 16 July 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]