Evidence of the occurrence, detection, and ecotoxicity studies of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in aqueous environments.

Perflorochemicals (PFCs), among which are the most commonly detected perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are persistent emergent contaminants of concern in recent times. These compounds have been reported for their cytotoxicity, genotoxicity, carcinogenicity, immunotoxicity, and developmental toxicities. Meanwhile, they have been detected in diverse matrices such as soil, sediment, and, surprisingly, in serum and even breastmilk.

Understanding Anionic Hyperporphyrins: TDDFT Calculations on Peripherally Deprotonated -Tetrakis(4-hydroxyphenyl)porphyrin.

Presented herein is a DFT/TDDFT study of -tetrakis(4-hydroxyphenyl)porphyrin (H[THPP]) and its -deprotonated tetraanionic form; the latter was modeled as both a free tetraanion and with various counterions. Based on our calculations, the experimentally observed hyperporphyrin spectra are attributed to an admixture of phenol/phenoxide character into the a-type HOMO of tetraphenylporphyrin. The admixture results in an elevation of the orbital energy of the HOMO in relation to other frontier orbitals, which accounts for the observed spectral redshifts.

Assessing Computational Methods to Calculate the Binding Energies of Dimers of Five-Membered Heterocyclic Molecules.

Computational electronic structure methods, including ab initio and density functional theory (DFT), have been assessed in calculating the binding energies of 14 five-membered heterocyclic dimers. The configurations were generated using classical molecular dynamics before optimization at the MP2/aug-cc-pVTZ. Benchmark binding energies are calculated at the CCSD(T)/CBS level of theory.

Unexpected XPS Binding Energy Observations Further Highlighted by DFT Calculations of Ruthenocene-Containing [Ir(ppy)(RCOCHCORc)] Complexes: Cytotoxicity and Crystal Structure of [Ir(ppy)(FcCOCHCORc)].

The series of iridium(III) complexes, [Ir(ppy)(RCOCHCOR')], with R = CH and R' = CH (), Rc (), and Fc (), as well as R = Rc and R' = Rc () or Fc (), and R = R' = Fc (), ppy = 2-phenylpyridinyl, Fc = Fe(η-CH)(η-CH), and Rc = Ru(η-CH)(η-CH), has been investigated by single-crystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS) supplemented by DFT calculations. Here, in the range of 3.74 ≤ Σχ ≤ 4.