skip to main content

Search for: All records

Award ID contains: 1664799

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Acyl(chloro)phosphines RC(O)P(Cl)( t -Bu) have been prepared by formal insertion of tert -butyl phosphinidene ( t -Bu–P) from t -BuP A ( A = C 14 H 10 or anthracene) into the C–Cl bond of acyl chlorides. We show that the under-explored acyl(chloro)phosphine functional group provides an efficient method to prepare bis(acyl)phosphines, which are important precursors to compounds used industrially as radical polymerization initiators. Experimental and computational investigations into the mechanism of formation of acyl(chloro)phosphines by our synthetic method reveal a pathway in which chloride attacks a phosphonium intermediate and leads to the reductive loss of anthracene from the phosphorus center in a P( v ) to P( iii ) process. The synthetic applicability of the acyl(chloro)phosphine functional group has been demonstrated by reduction to an acylphosphide anion, which can in turn be treated with an acyl chloride to furnish dissymmetric bis(acyl)phosphines. 
    more » « less
  2. Formal addition of diazomethane's terminal nitrogen atom to the 9,10-positions of anthracene yields H 2 CN 2 A ( 1 , A = C 14 H 10 or anthracene). The synthesis of this hydrazone is reported from Carpino's hydrazine H 2 N 2 A through treatment with paraformaldehyde. Compound 1 has been found to be an easy-to-handle solid that does not exhibit dangerous heat or shock sensitivity. Effective umpolung of the diazomethane unit imbues 1 with electrophilicity at the methylene carbon center. Its reactivity with nucleophiles such as H 2 CPPh 3 and N-heterocyclic carbenes is exploited for CC bond formation with elimination of dinitrogen and anthracene. Similarly, 1 is demonstrated to deliver methylene to a nucleophilic singlet d 2 transition metal center, W(ODipp) 4 ( 2 ), to generate the robust methylidene complex [ 2 CH 2 ]. This behavior is contrasted with that of the Wittig reagent H 2 CPPh 3 , a more traditional and Brønsted basic methylene source that upon exposure to 2 contrastingly forms the methylidyne salt [MePPh 3 ][ 2 CH]. 
    more » « less
  3. Targeted as an example of a compound composed of a carbon atom together with two stable neutral leaving groups, 7-isocyano-7-azadibenzonorbornadiene, CN 2 A ( 1 , A = C 14 H 10 or anthracene) has been synthesized and spectroscopically and structurally characterized. The terminal C atom of 1 can be transferred: mesityl nitrile oxide reacts with 1 to produce carbon monoxide, likely via intermediacy of the N -isocyanate OCN 2 A . Reaction of 1 with [RuCl 2 (CO)(PCy 3 ) 2 ] leads to [RuCl 2 (CO)( 1 )(PCy 3 ) 2 ] which decomposes unselectively: in the product mixture, the carbide complex [RuCl 2 (C)(PCy 3 ) 2 ] was detected. Upon heating in the solid state or in solution, 1 decomposes to A , N 2 and cyanogen (C 2 N 2 ) as substantiated using molecular beam mass spectrometry, IR and NMR spectroscopy techniques. 
    more » « less
  4. Tungsten( iv ) tetrakis(2,6-diisopropylphenoxide) ( 1 ) has been demonstrated to be a competent platform for decarbonylative formation of anionic terminal pnictide complexes upon treatment with pnictaethynolate anions: cyanate, 2-phosphaethynolate, and 2-arsaethynolate. These transformations constitute the first examples of terminal phosphide and arsenide complex formation at a transition metal center from OCP − and OCAs − , respectively. The phosphide and arsenide complexes are also the first to be isolated in a tetragonal, all-oxygen ligand environment. The scalar NMR coupling constants between tungsten-183 and nitrogen-15 or phosphorus-31 have been measured and contextualized using natural bond orbital (NBO) methods in terms of s orbital character in the σ bonding orbital and pnictide lone pair. 
    more » « less