RESUMO
Photoexcitation of a dimeric gold complex showed the activation of a C(sp(2))-Br bond to generate a vinyl radical in a mild photoredox catalysis process. Use of [Au2(dppm)2]Cl2 with 365 nm LEDs in a photoredox catalysis process to produce polycyclic scaffolds using vinyl radicals is reported. This method achieved the synthesis of a small library of butenolide polycyclic compounds and naphthol polycyclic compounds. The efficacy of this photoredox process was further demonstrated by accomplishing the concise formal synthesis of (±)-triptolide.
RESUMO
Remote coordination of a Ru(hfac)2 moiety to a chelating N-benzyl tetrazine lowers the C-N homolytic bond dissociation enthalpy by approximately 20 kJ mol(-1). The significant bond strength perturbation is believed to arise as a consequence of metal-ligand redox non-innocence.
RESUMO
The optimum experimental geometry for visible-infrared sum-frequency generation experiments depends rather sensitively on the molecules adsorbed at the surface, their orientation, and the nature of the adjacent bulk media. We consider the commonly encountered case of methyl groups situated at air-water, air-gold, and polymer-water interfaces. We provide expressions that may be used to determine the optimal visible and IR beam incident angles, considering the symmetric and antisymmetric modes separately and then together. The analysis is carried out for co-propagating (collinear and non-collinear geometries) and counter-propagating configurations. We first consider that one or more vibrational modes are of interest, and the goal is to study them quantitatively under a single polarization scheme; our results enable the user to set the beam angles for such an experiment. In the second case, molecular orientation information is desired, and so the calibrated response is required in all accessible polarization schemes for full characterization of the nonlinear susceptibility tensor.