scholarly journals Generation of Iminophosphoranes and Phosphorus Ylides from (Alkylamino) phosphonium Salts and their Reactions with Isocyanates. Mechanism Elucidation by the DFT Method

2006 ◽  
Vol 74 (9) ◽  
pp. 758-767 ◽  
Author(s):  
Yuichi OKAZAKI ◽  
Akimasa TAKEUCHI ◽  
Fumio ANDO ◽  
Jugo KOKETSU
2014 ◽  
Vol 68 (5) ◽  
Author(s):  
Seyyed Sabounchei ◽  
Mohammad Panahimehr ◽  
Hamid Khavasi ◽  
Fateme Bagherjeri ◽  
Collete Boscovic

AbstractThe reaction of dppm (1,1-bis(diphenylphosphino)methane) with 2-bromo-4-phenylacetophenone and benzyl bromoacetate in chloroform produces new phosphonium salts, [Ph2PCH2PPh2CH2C(O) C6H4Ph]Br (I) and [Ph2PCH2PPh2CH2COOCH2Ph]Br (II). By allowing the phosphonium salts to react with the appropriate base, the bidentate phosphorus ylides, Ph2PCH2PPh2=C(H)C(O)C6H4Ph (III) and Ph2PCH2PPh2=C(H)C(O)OCH2Ph (IV), were obtained. The reaction of these ligands with mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX2[(Ph2PCH2PPh2C(H)C(O)C6H4Ph)]} (X = Cl (V); X = Br (VI); X = I (VII)) and {HgX2[(Ph2PCH2PPh2C(H)COOCH2Ph)]} (X = Cl (VIII); X = Br (IX); X = I (X)). The FTIR and 1H, 31P and 13C NMR spectra were studied. The structure of compound III was unequivocally determined by the single-crystal X-ray diffraction technique. Single-crystal X-ray analysis of the {HgBr2[(Ph2PCH2PPh2C(H)C(O)C6H4Me)]} complex (XI) revealed the presence of a mononuclear complex containing the Hg atom in a distorted tetrahedral environment. In all complexes, the ylides referred to above were coordinated through the ylidic carbon and the phosphine atom.


1984 ◽  
Vol 39 (5) ◽  
pp. 618-622 ◽  
Author(s):  
Graham A. Bowmaker ◽  
Cornelia Dörzbach ◽  
Hubert Schmidbaur

The reaction of CuCl2 with equimolar quantities of an ylide R3P=CH2 (1a-c, R=CH3, C2H5, C6H5) in anhydrous tetrahydrofuran at low temperature leads to oxidative coupling, with ethylidene-1,2-bis-phosphonium salts R3P⊕-CH2-CH2-P⊕R3 2X⊖ (2, 3a-c) as high- yield products. The process is interpreted as a one-electron transfer to give radical cations R3P⊕-ĊH2 (II) which subsequently undergo dimerization. The initial counterions CuCl2⊖ (in 2a-c) can be replaced by PF6⊖ (as in 3a-c). (C2H5)3P=CHCH3 (1d) yields the cation (C2H5)3P⊕-*CH(CH3)-*CH(CH3)P⊕(C2H5)3 with two chiral centers as a mixture of diasteromers RR/SS, RS. The ratio of the components is 2,8:1. as evaluated by NMR spectroscopy.The analogous reaction with (C6H5)3P=CHCH3 and (C6H5)3P=C(CH3)2 (1e, f) takes a very different course. Along with minor quantities of (C6H5)3P⊕CH2CH3/(C6H5)3P⊕CH(CH3)2 species, mainly 1-chloroalkyl-phosphonium cations are formed, which were again isolated as the hexafluorophosphates (4a, 4b: [(C6H5)3P⊕CH(CI)CH3]PF6⊕, [(C6H5)3P⊕C(Cl)(CH3)2]Pf6⊖). H-radical trapping from the medium by II ist proposed for the formation of the former, while a two- electron oxidation followed by addition of Cl⊖ is the most plausible mechanism for the generation of the latter


1977 ◽  
Vol 32 (11) ◽  
pp. 1268-1270 ◽  
Author(s):  
Lothar Knoll

Triphenylmethylene- and triphenylethylidenephosphorane react with h5-cyclopentadienyl-dicarbonylironiodide to yield the yellow stable complexes of the type[h5-C5H5Fe(CO)2-CHRP(C6H5)3]I (R = H (1), CH3 (2)).By reaction of 1 and 2 with AgBF4 the corresponding BF4-salts can be isolated. The new compounds are characterized by their 1H NMR, 31P NMR and IR spectra as well as by elemental analysis.


Polyhedron ◽  
2015 ◽  
Vol 87 ◽  
pp. 349-353 ◽  
Author(s):  
Ali Naghipour ◽  
Khadijeh Badpa ◽  
Behrouz Notash

2019 ◽  
Author(s):  
Minho Kim ◽  
won june kim ◽  
Tim Gould ◽  
Eok Kyun Lee ◽  
Sébastien Lebègue ◽  
...  

<p>Materials design increasingly relies on first-principles calculations for screening important candidates and for understanding quantum mechanisms. Density functional theory (DFT) is by far the most popular first-principles approach due to its efficiency and accuracy. However, to accurately predict structures and thermodynamics, DFT must be paired with a van der Waals (vdW) dispersion correction. Therefore, such corrections have been the subject of intense scrutiny in recent years. Despite significant successes in organic molecules, no existing model can adequately cover the full range of common materials, from metals to ionic solids, hampering the applications of DFT for modern problems such as battery design. Here, we introduce a universally optimized vdW-corrected DFT method that demonstrates an unbiased reliability for predicting molecular, layered, ionic, metallic, and hybrid materials without incurring a large computational overhead. We use our method to accurately predict the intercalation potentials of layered electrode materials of a Li-ion battery system – a problem for which the existing state-of-the-art methods fail. Thus, we envisage broad use of our method in the design of chemo-physical processes of new materials.</p>


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