35387-44-1Relevant articles and documents
31P NMR spectroscopic analysis on photooxidation of 1,n-bis(diphenylphosphino)alkanes with the aid of DFT calculations
Yasui, Shinro,Yamazaki, Shoko
, (2020/02/15)
The chloroform-d solution of diphosphine, 1,n-bis(diphenylphosphino)alkane (Ph2P(CH2)nPPh2; n = 1-6), was photolyzed with light from a xenon lamp in air. The progress of the reaction was followed by 31P NMR spectroscopy. The observed spectral change showed that the diphosphine is initially oxidized to diphosphine monoxide, Ph2P(═O)(CH2)nPPh2, which is further oxidized to diphosphine dioxide, Ph2P(═O)(CH2)nP(═O)Ph2. The oxidation of the diphosphine to the diphosphine monoxide took place according to first-order kinetics with respect to the concentration of the diphosphine, the first-order rate constant, kobs, being larger with increasing number of the methylene units in the spacer. The observation in kinetics is interpreted based on the conformation of the diphosphine radical cation intermediate initially generated by electron transfer from the photoexcited diphosphine to oxygen. Density functional theory (DFT) calculations predict that the diphosphine radical cation takes “folded” conformation where two phosphorus atoms are arranged closely to each other. The “folded” conformer of the diphosphine radical cation results from electrostatic interaction of these two phosphorus atoms. This conformer explains the observed dependency of kobs on the length of the spacer in the diphosphine.
Syntheses and crystal structures of organoindium(III) 1-D coordination polymers with bis(diphenylphosphino)alkane dioxides
Peppe, Clovis,Mello, Melina De Azevedo,Martins, Felipe Terra,Vargas, Jaqueline Pinto,Wouters, Felipe Christoff,Burrow, Robert Alan,Cangussu, Danielle,Das Chagas, Rafael Pav?o
, p. 813 - 827 (2018/03/01)
Bromomethyl-dibromo-indium(III), Br2InCH2Br, obtained from indium monobromide and methylene dibromide, reacts with hard and soft donor ligands to afford the corresponding indium(III) organometallic complexes. In this work, we investigated the conditions to prepare adducts of Br2InCH2Br using bis(diphenylphosphino)alkane dioxides acting as hard ligands. We report here the synthesis and crystal structures of two 1-D coordination polymers with the hard donor ligands Ph2P(O)(CH2)mP(O)Ph2 (m?=?2, dppeO2 and m?=?6, dpphO2). Compounds 1 and 2 with formulas [Br2In(CH2Br)(dppeO2)]n (1) and [Br2In(CH2Br)(dpphO2)]n (2) were characterized by IR and Raman spectroscopy and elemental analysis. We also obtained an ionic indium(III) compound with dppeO2 acting as a chelating ligand with formula [InBr2(dppeO2)2][InBr3(CH2Br)] (3). The crystal structures were determined for 1–3 using single crystal X-ray diffractometry. The geometry around the In(III) can be described as a trigonal bipyramid in 1 and 2, and the chains were packed onto the plane giving layers that are stabilized mainly by intermolecular interactions. Compound 3 has a square bipyramidal In(III) cation with formula [Br2L2In]+ and tetrahedral organoindium(III) anion with formula [Br3InCH2Br]–. Hirshfeld surface analysis employing 2-D fingerprint plots have been used to analyze intramolecular and intermolecular interactions present in the solid state of the structures.
Reduction of tertiary phosphine oxides with DIBAL-H
Busacca, Carl A.,Raju, Ravinder,Grinberg, Nelu,Haddad, Nizar,James-Jones, Paul,Lee, Heewon,Lorenz, Jon C.,Saha, Anjan,Senanayake, Chris H.
, p. 1524 - 1531 (2008/04/12)
(Chemical Equation Presented) The reduction of tertiary phosphine oxides (TPOs) and sulfides with diisobutylaluminum hydride (DIBAL-II) has been studied in detail. An extensive solvent screen has revealed that hindered aliphatic ethers, such as MTBE, are optimum for this reaction at ambient temperature. Many TPOs undergo considerable reduction at ambient temperature and then stall due to inhibition. 31P and 13C NMR studies using isotopically labeled substrates as well as competition studies have revealed that the source of this inhibition is tetraisobutyldialuminoxane (TIBAO), which builds up as the reaction proceeds. TIBAO selectively coordinates the TPO starting material, preventing further reduction. Several strategies have been found to circumvent this inhibition and obtain full conversion with this extremely inexpensive reducing agent for the first time. Practical reduction protocols for these critical targets have been developed.
