We document soil and groundwater contamination caused by industrial airborne PFAS emission over an area of ∼200 km2 that has impacted over 1200 wells.

The implicit rigidity imparted by the alkene backbone in cisand trans-1,2-bis(diphenylphosphino)ethylene (dppee) has made

The crystal structures for cis‐(Ph2PCH=CHPPh2)(AuI)2 and trans‐(Ph2PCH=CHPPh2)(AuI)2 are reported. The structure of cis‐(Ph2PCH=CHPPh2)(AuI)2 reveals a short intramolecular Au–Au distance of 2.9526(5) Å, while the structure of trans‐(Ph2PCH=CHPPh2)(AuI)2 shows intermolecular Au–Au distances of 3.2292(7) Å. Structural data for the iodide complexes are compared to previously reported crystal structural data for cis‐ and trans‐(Ph2PCH=CHPPh2)(AuCl)2 and dppbz(AuCl)2. The quantum yields for the photochemical isomerization of cis‐(Ph2PCH=CHPPh2)(AuX)2 with 334‐nm light, Φ(cis → trans), are 0.204, 0.269, and 0.363 for X = Cl, Br, and I, respectively. Prior results from ab initio calculations on the model cis‐ and trans‐Au2X2C2H2(PH2)2 complexes aid in the interpretation of the correlation between the quantum yield for isomerization and the calculated aurophilic attraction potential V(Re). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

No abstract

The unusual yellow color of Au2(dppm)(SR)2 (R = 4-tolyl; dppm = diphenylphosphinomethane) is attributed to a red-shift in the S→Au charge transfer caused by destabilization of the sulfur highest occupied molecular orbital (HOMO). Variable temperature experiments show two broad bands at -80°C in the 31P{1H} NMR spectrum of Au2(dppm)(SR)2 and the activation energy for interconversion is 10 kcal/mol. Only one sharp band is observed down to -80°C in the spectrum of the white complex, Au2(dppe)(SR)2 (dppe = diphenylphosphinoethane). Molecular mechanics calculations on Au2(dppm)(SR)2 and Au2(dppe)(SR)2 reveal that, for Au2(dppe)(SR)2, a series of maxima and minima, separated by 2.5 kcal/mol, occur every 120° which is consistent with rotation around an unhindered carbon-phosphorus single bond. The Au atoms are not within bonding distance in any conformation. Computational results for Au2(dppm)(SR)2 indicate one minimum energy structure in which the Au-P bonds are anti. There is a high energy conformation (9 kcal/mol above the global minimum) where overlap between golds is maximized. The implications of gold-gold bonding in this complex are discussed. The steric influence of the thiolate ligand has been examined by synthesizing a series of dinuclear gold(I) complexes in which the steric properties of the thiolate are varied: Au2(dppm)(SR)2 (R = 2,6-dichlorophenyl; 2,6-dimethylphenyl; 3,5-dimethylphenyl). The 2,6-disubstituted complexes are white, while the 3,5-dimethyl complex is yellow. These results, along with VT-NMR experiments, are consistent with the conclusion that the more sterically-bulky thiolates hinder the close approach of the golds in the dinuclear complexes.

No abstract

No abstract

No abstract