993-11-3Relevant academic research and scientific papers
A simple access to tetramethylphosphonium iodide
Herrmann, Florian,Kuhn, Norbert
, p. 853 - 854 (2012/11/13)
Tetramethylphosphonium iodide is prepared from calcium phosphide and methyl iodide in methanol/water in good yield.
Advances in trifluoromethylating phosphorus compounds
Kolomeitsev, Alexander,Goerg, Michaela,Dieckbreder, Uwe,Lork, Enno,Roeschenthaler, Gerd-Volker
, p. 597 - 600 (2007/10/03)
The System CF3IMe3P is re-investigated and Me2PCF3, Me4P+I-, (CF3)2PMe3, Me3PI2, [Me3(CF3)P]+I- are found as products. Using CF3Br/P(NEt2)3 the phosphines R12PCF3 and R1P(CF3)2 (e.g. R1 = Me, iPr, NEt2) can be obtained which are precursors either for phosphoranes (e.g. 1,2λ5σ5-oxaphosphetanes) or phosphonium salts (e.g. [R12(Me)PCF3]+X- or [R1(Me)P(CF3)2X-]. The latter are deprotonated to furnish methylene phosphoranes R12(CH2=)PCF3 or R1(CH2=)P(CF3)2, reactive synthons. From CF3Br/ P(NEt2)3/P(OPh)3 the phosphine P(CF3)3 is available, which turned out to be a potent electrophile. Amido phospites ROP(NEt2)2 and halides R2X (R2= CCl2CF3, X= Cl; R2= CF=CFCF3, X= F; R2= C6F5, X= Br, I; R2= C(CF3)3, X= Br; R2= SCF3, X= CF3) undergo an ARBUZOV reaction.
Twelve-electron organochromium species: Synthesis and characterization of high-spin square-planar chromium(II) alkyls and aryls
Hermes, Ann R.,Morris, Robert J.,Girolami, Gregory S.
, p. 2372 - 2379 (2008/10/08)
Alkylation of the chromium phosphine complex [CrCl2(dippe)]2 (dippe = 1,2-bis(diisopropyl-phosphino)ethane) with Grignard or dialkylmagnesium reagents gives the unusual 12-electron chromium(II) alkyls cis-CrR2(dippe) (R = CH2CMe3, CH2SiMe3, C6H2Me3). The unidentate phosphine complex trans-Cr(C6H2Me3)2(PMe 3)2 may be prepared similarly by treatment of CrCl2(THF) with dimesitylmagnesium in the presence of PMe3. All of these four-coordinate alkyls possess magnetic moments characteristic of high-spin species, μ = 4.9 μB, and exhibit broadened 1H NMR resonances consistent with the paramagnetism. X-ray crystal structures of Cr(CH2CMe3)2(dippe) and Cr(CH2SiMe3)2(dippe) reveal tetrahedrally distorted square-planar structures, where the dihedral angle between the C-Cr-C and P-Cr-P planes is larger in the neopentyl complex, 28.4° vs 15.8°, due to steric effects. For similar reasons, the Cr-C and Cr-P distances in the neopentyl compound of 2.149 (8) and 2.556 (2) A? are slightly longer than those of 2.128 (4) and 2.517 (1) A? in the (trimethylsilyl)methyl derivative, and the C-Cr-C angle is also larger in the neopentyl complex at 101.9 (3)° vs 95.7 (2)°. In contrast to these results, the mesityl complex Cr(C6H2Me3)2(PMe3) 2 is essentially flat: the ipso carbon atoms and the phosphorus atoms are +0.9° and -0.9° out of the mean CrC2P2 plane, respectively. The Cr-C and Cr-P distances in this molecule are 2.130 (6) and 2.462 (2) A?, while all the C-Cr-P angles fall between 89.3 (2)° and 90.8 (2)°. Crystal data: for Cr(CH2CMe3)2(dippe), space group C2/c, a = 15.867 (5) A?, b = 10.401 (4) A?, c = 18.154 (6) A?, β = 106.67 (3)°, V = 2870 (2) A?3, Z = 4, RF = 5.9%, RwF = 7.7% on 126 variables and 1205 data; for Cr(CH2SiMe3)2(dippe), space group C2/c, a = 15.666 (4) A?, b = 10.983 (3) A?, c = 18.099 (6) A?, β = 102.43 (2)°, V = 3041 (1) A?3, Z = 4, RF = 4.1% RwF = 4.6% on 128 variables and 1472 data; for Cr(C6H2Me3)2(PMe3) 2, space group P21/n, a = 9.710 (2) A?, b = 14.121 (3) A?, c = 19.446 (3) A?, β = 98.36 (1)°, V = 2638.0 (9) A?3, Z = 4, RF = 5.1%, RwF = 6.1% on 260 variables and 2199 data. The chromium alkyls are able to polymerize ethylene slowly at 25°C and 10 atm.
13C and 31P NMR Studies of Some Aminophosphonium Chlorides
Krannich, Larry K.,Kanjolia, Ravindra K.,Watkins, Charles L.
, p. 320 - 324 (2007/10/02)
The multinuclear NMR spectral data for an homologous series of tertiary phosphines R(3-n)P(NMe2)(n), aminophosphonium ions, (+), and phosphonium ions, (+), where R=Me, Et, (n)-Pr and Ph, R' and/or R''=H, Me and n=0 and 1 are reported and discussed.Quaternization by alkylation or alkylation or chloramination causes an increase in the 31P chemical shift (ΔδP is positive), a decrease in the 13C chemical shift (ΔδC is negative) for all carbons, an increase in the magnitudes of 1J(PC), 3J(PC), 3J(PNCH) and 2J(PCH) and a decrease in the magnitude of 2J(PC).Substitution of a Me2N group for an alkyl or aryl group produces an increase in the 31P chemical shift and in the magnitude of 1J(PC). α- and β-deshielding and γ-shielding effects are noted in the 13C NMR spectra and β-deshielding and γ-shielding effects are noted in the 31P NMR spectra with substitution on the phosphorus and nitrogen atoms. - Key words: 13C NMR, 31P NMR, Tertiary phosphines, Aminophosphonium ions, Phosphonium ions
ZUR REAKTION VON METALL-KOORDINIERTEM KOHLENMONOXID MIT YLIDEN. VIII. TRIMETHYL(METHYLEN)PHOSPHORAN-KATALYSIERTE ISOMERISIERUNG EINES EISENACYL-PHOSPHORYLIDS. UEBERTRAGUNG DER Cp(CO)2FeC(O)-EINHEIT ZWISCHEN YLIDISCHEN ZENTREN
Blau, Herbert,Malisch, Wolfgang
, p. C1 - C6 (2007/10/02)
The addition of MeI to the ironacyl phosphorusylide Cp(CO)2FeC(O)CH=PMe3 (I) gives the phosphonium salt I (II), which can be dehydrohalogenated with Me3P=CH2 to the corresponding ylide Cp(CO)2FeC(O)(Me)C=PMe3 (III).III is thermally stable in the pure state, but rearranges irreversibly with the addition of a trace of Me3P=CH2 to the thermodynamically favored isomer Cp(CO)2FeC(O)HC=PEtMe2 (IV).A plausible mechanism for the rearrangement is established, involving the intermolecular transfer of the Cp(CO)2FeC(O)-group between the tautomeric ylides Me3P=CHMe and EtMe2P=CH2.It is proved by the simple reaction of Cp(CO)2FeC(O)(Me)C=PEt3 (V) with Me3P=CH2 to give quantitatively I and Et3P=CHMe.The first ylide rearrangement involving the shift of a transition metal group is mainly induced by the better electronic stabilization of the ylidic function, when the Cp(CO)2FeC(O) moiety is combined with a hydrogen atom.
Functional Derivatives of Trimethylphosphane, XVII. Methyl-bis(dimethylphosphinomethyl)phosphane, (Me2PCH2)2PMe
Karsch, Hans H.
, p. 284 - 291 (2007/10/02)
(Me2PCH2)2PMe (3) is obtained from MePCl2 (2a) or MeP(OPh)2 (2b) and LiCH2PMe2 (1).The oxides 2PMe (4) and 2P(O)Me (5), are formed on the reaction with air.Quaternisation with MeI gives the salts I2 (6) and I3 (12).For comparison, also the isoelectronic (Me3SiCH2)2PMe (7), and (Me3SiCH2)2PtBu (8), are synthesized and transformed to their methylphosphonium salts 10 and 11.With CH2Br2 3 forms the six-membered heterocycle Br2 (13a), which could not be isolated in a pure state, however. 3 may be m etalated by LiBu: Li (15), is obtained, but a second metalation step could not be observed.The hydrolysis of 12 under unusual mild conditions (H2O or H2O/CH3OH) gives I (16), and I (17), as main products.Properties and NMR data of the new compounds are described. - Key words: Triphosphane (PCPCP), Phosphonium Salts, Hydrolysis, NMR Spectra
