Cationic Gold(II) Complexes: Experimental and Theoretical Study**

Abstract

Gold(II) complexes are rare and their application for catalysis of chemical transformations is unexplored. The reason is their easy oxidation or reduction to the more stable gold(III) or gold(I) complexes, respectively. We explored the thermodynamics of the formation of the [(L)Au II X] + complexes (L = ligand, X = halogen) from their gold(III) precursors and investigated the stability and the spectral properties in the IR and VIS range of the formed gold(II) complexes in the gas phase. The results show that the best ancillary ligands L for stabilizing gaseous [(L)Au II X] + complexes are bidentate and tridentate ligands with nitrogen donor atoms. The electronic structure and spectral properties of the investigated gold(II) complexes were correlated with the quantum chemical calculations. The results show that the molecular and electronic structure of the gold(II) complexes as well as their spectroscopic properties are very similar to the analogous stable copper(II) complexes.

Highly oxidized U(vi) within the smallest fullerene: gas-phase synthesis and computational study of boron-doped U@C27B

“…Localization index (LI), a QTAIM-based index that defines the population of an atomic basin minus the shared electrons, has been used recently to measure the oxidation state of electropositive atoms. 44,45 The difference between the LI and atomic number provides a measure of the charge of an atom after the ionic approximation for heteroatomic bonds, which corresponds to the IUPAC definition of oxidation state. Measure of LI U in U@C 27 B also confirms the U(VI) oxidation state.…”

[Sc©[3]CPP]+: A Viable Metal-Centered [3]Cycloparaphenylene

“…To verify the formal charge state of center metal atoms, we calculated the localization indices (LI) , for [M©[3]­CPP] complexes, and the values are 9.80, 9.90, 17.64, 17.88, and 7.69 |e| for Na, Mg, Ca, Sc, and Y in [Na©[3]­CPP] − , [Mg©[3]­CPP], [Ca©[3]­CPP], [Sc©[3]­CPP] + , and [Y©[3]­CPP] + complexes, respectively. Considering the number of electrons in neutral metals, 11, 12, 20, 21, and 11 for Na, Mg, Ca, Sc, and Y, the differences of 1.20, 2.10, 2.36, 3.12, and 3.31 |e| indicate that these metals should be Na + , Mg 2+ , Ca 2+ , Sc 3+ , and Y 3+ , respectively.…”

“…To verify the formal charge state of center metal atoms, we calculated the localization indices (LI) 54,55 for [M© [3] 3+ , and Y 3+ , respectively. Please note that when the def2-TZVPP basis set is used, 28 core electrons of Y are included in the effective core potential, so Y only has 11 electrons (39−28) in this case.…”

Copper(II)‐TEMPO Interaction

“…Our laser source loses power below 420 nm (dotted lines in Figure 3); hence, the bands are likely broad towards the lower wavelength. Recently, we analyzed electronic excitations of the [Cu(bipy)X] + (X=Cl and Br) complexes [37] . The spectra contained a band corresponding to the σ(M−X)>π(M−X)* transition (<450 nm for X=Cl and 500 nm for X=Br).…”

“…Recently, we analyzed electronic excitations of the [Cu-(bipy)X] + (X=Cl and Br) complexes. [37] The spectra contained a band corresponding to the σ(MÀ X) > π(MÀ X)* transition (< 450 nm for X=Cl and 500 nm for X=Br). In analogy, the bands in the spectra presented here most likely correspond to the transition σ(MÀ OR) > π(MÀ OR)* (OR = the alcoholato or phenolato ligand).…”