Photosensitized Hydride Transfer. Highly Regioselective 1,4-Photoreduction of NAD(P)+Models under Visible Light with an Organometallic Rhodium(III) Porphyrin as Sensitizer
Solvent Effects on Hydride Transfer from Cp*(P-P)FeH to BNA+ Cation
摘要:
Examining of the hydride transfer reaction between Cp*((Ph2PNPPh2)-P-tBu)FeH ((Ph2PNPPh2)-P-tBu = N,N-bis(diphenylphosphanyl)tert-butylamine, 1-H) and 1-benzyl-3-carbamoylpyridinium cation (BNA(+)) in different solvents, we found that the solvents exert considerable influence on the hydride transfer processes. A coordinating solvent molecule such as MeCN is not only a ligand which stabilizes the organo-iron fragment producing [Cp*((Ph2PNPPh2)-P-tBu)Fe(NCMe)](+) ([1(NCMe)](+)), but also assists the hydride transfer. In THF, reaction of 1-H with BNA+ under high pressure of nitrogen (60 psi) giving the iron(II)-nitrogen complex [Cp*((Ph2PNPPh2)-P-tBu)Fe(N-2)](+) ([1-N-2](+)) and BNAH. In CH2Cl2, [1-N-2](+) catalyzes the conversion of 1-H to Cp*((Ph2PNPPh2)-P-tBu)FeCl (1-Cl), which hampers the expected hydride transfer reaction. In the presence of MeCN, the hydride transfer process in THF, CH2Cl2, or benzene was achieved affording the reduced BNAH and [1(NCMe)](+). New iron complexes in the [Cp*((Ph2PNPPh2)-P-tBu)FeX](n+) series (where n = 0, X = H or Cl; n = 1, X = MeCN, N-2, or Cl-) were obtained and well characterized.