“…After pentane extraction the two products were separated using chromatography on a silica gel column with dichloromethane eluent and were shown to be the chlorophosphirene 19 and [CpFe(CO) 2 F] (20) (Scheme 12). The spectra of 19 [29] and 20 [30] are consistent with the published data.…”
“…After pentane extraction the two products were separated using chromatography on a silica gel column with dichloromethane eluent and were shown to be the chlorophosphirene 19 and [CpFe(CO) 2 F] (20) (Scheme 12). The spectra of 19 [29] and 20 [30] are consistent with the published data.…”
“…Quite surprisingly, the reactivity of 2a , b strongly differs from that of 2c . Whereas both metallacycles ( 2a , b ) do not react with PhPCl 2 , whatever the solvent used, they react with PCl 3 in dichloromethane to give the corresponding 1-chlorophosphirenes 3a,b , as attested by 31 P NMR spectroscopy (δ( 3a in CH 2 Cl 2 ) −83.4 ppm; δ( 3b in CH 2 Cl 2 ) −71.3 ppm) (eq 2). …”
Section: Resultsmentioning
confidence: 99%
“…Phosphirenes 3a,b have recently been synthesized by us using a metallacycle transfer reaction from the corresponding titanacyclopropene complex . It must be noted that this transformation in the case of zirconium is not totally unprecedented.…”
A synthetic approach toward mixed phosphinine−phosphole and phosphinine−phosphaferrocene tridentate ligands has been studied. In the first step, the metallacycle transfer
reaction from 2,5-bis(trimethylsilyl)zirconacyclopentadienes to the corresponding phospholes
has been investigated. Three metallacycles 2a−c, bearing different groups at the β-positions
of the ring (a, R = Ph; b, R = n-Bu; c, R = Me), have been synthesized. Whereas the reaction
of PCl3 with 2a,b respectively leads to 1-P chlorophosphirenes 3a,b, complex 2c is readily
transformed into the corresponding 1-P bromophosphole 4 upon reaction with PBr3 in
dichloromethane. This approach was extended to the synthesis of the bis(dimethylpropynylsilyl)zirconacyclopentadiene compound 5, which was then further converted into the
corresponding 1-P chlorophosphole 6. Phospholyl anion 7 was obtained from the reaction of
6 with lithium in THF at room temperature. Three 1-R-2,5-bis(dimethylpropynylsilyl)phospholes (8a, R = CH2CH2Cl; 8b, R = CH2CH2CN; 8c, R = CH2CH2CO2Et) have been
obtained from the reaction of anion 7 with the corresponding species RCH2CH2X (X = Cl,
Br). The X-ray crystal structure of compound 8b has been determined. The reaction of anion
7 with [FeCp(η6-C9H12)][PF6] and FeCl2 respectively yielded the monophosphaferrocene 9
and the diphosphaferrocene 10. The X-ray crystal structure of 10 has been determined. The
three phosphinine−phosphole tridentate ligands 12a−c have been assembled by reacting
phospholes 8a−c with diazaphosphinine 1 followed by reaction of the 2,5-bis(dimethyl(1,2-azaphosphininyl)silyl)phospholes 11a−c with (trimethylsilyl)acetylene in excess. Ligands
12b,c have been converted into the anion 13 upon reaction with LDA at low temperature.
The 2,5-bis(dimethyl(phosphininyl)silyl)phosphaferrocene ligand 15, which was structurally
characterized, has been prepared by following the strategy devised for the synthesis of ligands
12. Reaction of ligands 12a and 15 with [Rh(COD)Cl]2 gave respectively the corresponding
Rh chloride complexes 16 and 17. Both complexes adopt a square-planar geometry, and
complex 17 has been structurally characterized.
“…(20)]. [51] Electron-poor phosphaalkenes, generated at low temperature by a phospha-Wittig reaction [Eq. (11)], readily cycloadd to electron-rich alkenes or alkynes [Eq.…”
Since the beginning of the seventies, organophosphorus chemistry has been completely rejuvenated by the discovery of stable derivatives in which phosphorus has the coordination numbers one or two. The chemistry of these compounds mimics the chemistry of their all-carbon analogues. In this Review article this analogy is discussed for the phosphorus counterparts of alkenes, alkynes, and carbenes. In each case, the synthesis, reactivity, and coordination modes are briefly examined. Some special electronic configurations are also discussed, which include one-electron Pbond;P bonds, strained bonds, and aromatic systems. To conclude, some potential applications of this chemistry in the areas of molecular materials and homogeneous catalysis are presented.
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