The photolysis of dichlorotriphenylbismuth(V) in chloroform.
Under 254 nm irradiation in chloroform, Bi(C6H5)3Cl2 reacts to yield HBiCl4 and H2BiCl5, in contrast to its behavior in acetonitrile, in which bismuth metal appears to be the eventual product, unless anhydrous HCl is present, in which case H2BiCl5 is also formed. The photolysis in CHCl3 is not significantly solvent-initiated. The rate depends directly on the light intensity absorbed by the metal complex, and the quantum yield is 0.026. In CCl4 a portion of the reaction occurs through absorption of light by the solvent.
Photoredox Chemistry of Chloro Complexes of Antimony(III) and (V)
Abstract The complex [SbCl 6 ] 3− in CHCl 3 shows a phosphorescence (λ max = 520 nm, o = 2.4 X 10 −3 , τ ⩽ 50 ns) originating from the lowest sp excited state. Oxygen quenches this luminescence and participates in the photooxidation of Sb(III): [SbCl 6 ] 3− + O 2 → [SbCl 6 ] − + O 2 2− . At λ irr = 263 nm the quantum yield was o = 0.081. The photoproduct [SbCl 6 ] − in CHCl 3 is light-sensitive too. Ligand to metal charge transfer excitation induces a reduction of Sb(V): [SbCl 6 ] − + 2Cl − → [SbCl 6 ] 3− + Cl 2 . At λirr = 272 nm the quantum yield was o = 0.1. The photogenerated chlorine undergoes secondary reactions.
Highly enantio- and diastereoselective synthesis of β-methyl-γ-monofluoromethyl-substituted alcohols.
Enanatiopure β-methyl-γ-monofluoromethyl alcohols were prepared from the allylic alkylation between fluorobis(phenylsulfonyl)methane with Morita-Baylis-Hillman carbonates. The reaction was catalyzed by using the Cinchona alkaloid derivative, (DHQD)(2)AQN. The origin of the stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed stereoselectivity.