Reaktive EC(p-p)π-Systeme, XXVI. Einfache Synthese für Methylenphosphane (Phosphaalkene) des Typs HPC(F)NR2 und das Phosphaalkin PC-N(iPr)2 (original) (raw)
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Zeitschrift für Naturforschung B, 1996
The easily accessible phosphaalkene HP=C(F)NEt2 (lb) reacts with halophosphanes or -arsanes R2EX (X = Cl, I) in the presence of NEt3 to give P-phosphino- or -P-arsino substituted fluorophosphaalkenes of the type RiE-P=C(F)NEti (2 - 6) in high yields (60 - 85 %) [R2E: (CF3)2P (2), Me2N(CF3)P (3), Me2P (4), (CF3)2As (5), Me2As (6)]. The analogous reaction of ib with CF3PI2 (molar ratio 1:2) unexpectedly leads to the triphosphetene Et2N - C=P-PCF3-PCF3 (7). The stability of compounds 2 - 6 as a function of R2E decreases from As to P and from CF3 to Me, respectively. Compounds 2 - 6 generally show the Z-configuration and have been characterized by thorough spectroscopic investigations (MS,IR; 1H, 19F, 11C, 31PNMR). A single crystal X-ray diffraction study of 2 proves the π-type interaction of the nitrogen lone pair with the P=C bond thus enhancing the stability of the system and the PP bond order
Zeitschrift für Naturforschung B, 1985
Pyrolysis of the Diels-Alder adducts 2-4 yields F3CP = CF2 (1) and the corresponding dienes. For the thermal cleavage of 3 an alternative pathway in addition to the retro-diene reaction is observed, giving the new phosphetane F3 [xxx] and C4H4 dimers. The enthalpy of the cycloreversion reaction of 2 as well as estimated bond energies for the phosphorus-carbon σ- and π-bond have been determined from appearance potentials and thermochemical literature data. The products were characterized by mass and NMR spectra.
Zeitschrift für Naturforschung B
The reactions of F3C P = C F 2 (1) with M e,G eH. Me3SnH, and (C5R5)(C O)3MH (M = C r. Mo, W; R = H , Me) proceed via addition to the PC double bond yielding tertiary phosphanes of the type Me3M 'P (C F 3)C F2H [M' = Ge (2), Sn (3)] or (C5R5)(C O)3MP(CF3)CF2H [R = H; M-Cr (6), Mo (7). W (8); R = Me; M = Mo (9), W (10)]. 2 and 3 are labile compounds, which decompose by elimination of M e3M 'F , a reaction which in the case of 3 has been used to prepare the new phosphaalkene F3C P = C (H)F (5) and its [2+4]-cycloaddition product 4 with 2.3-dimethyl-1.3butadiene. The H substituent (instead of F) in 5 and its derivatives has a surprising influence not only on the stability of the com pounds but also on their spectroscopic data, as shown by com pari son with 1 and derivatives of the type Me3M 'P (C F 3)2 and (C5H 5)(C O)3M P(CF3)2. respectively. New com pounds are characterized by NM R, MS. GC/MS and IR measurem ents.
Zeitschrift für Naturforschung B, 1993
Trifluoromethyl-1,3-diphosphane tBu(H)PCF2P(H)CF3 (2) is formed regioselectively in almost quantitative yield by addition of tert-butylphosphane to perfluoro-2-phosphapropene F3CP=CF2 (1) as a 1:1 mixture of two diastereomers 2 a and 2b. 2 reacts with nickel tetracarbonyl to give the binuclear complex [tBu(H)PCF2P(H)CF3Ni(CO)2]2 (3) as the only isolable product. The mixture contains four of the eight possible isomers; one of them (3 a) could be isolated in pure form by crystallization from n-pentane solution. Attempts to generate the phosphaalkene tBu(H)PC(F)=PCF3 or the 1,3-diphosphaallene tBuP=C=PCF3 by HF elimination from 2 with NEt3, HNMe2 or HNEt2 lead to complicated mixtures of products. On the other hand, reaction of 3 a with isopropylamine affords the binuclear complex [(CO)Ni(F3CP=CFP(H)tBu)Ni(CO)2tBu(H)PCFHP(CF3)NHiPr] (4) with both a 16 eand an 18 e-nickel(O) fragment and a side-on coordinated F3CP=CF group. The new compounds were characterized by spectroscopic investigat...
Chemische Berichte, 1981
Die Titel-Triphosphaalkane (n = 0 -2; R, R' = Me, Ph) (3ad) wurden durch radikalische Addition primarer oder disekundarer Phosphane an die Allylgruppe der Ester R'P(O)(OiPr)-CH2CH = CH2 und nachfolgende LiAIH,-Reduktion der dabei erhaltenen Produkte dargestellt. 3 b (R = Me, R' = Ph. n = 1) laBt sich durch Metallierung mit Methyllithium und Umsetzung des erhaltenen Phosphidophosphans mit Methyliodid in guter Ausbeute in das permethylierte Derivat Me2P -[CH& -PPh -[CH& -PMe2 (3e) iiberfiihren. Die Liganden 3a -e bilden mit NiBr2 . 3 H 2 0 oder K2MCI, Komplexe MX2L (4 -6) (M = Ni", Pd" oder Pt''; X = CI, Br; L = 3ae), deren Konstitution durch Messung der elektrischen Leitfahigkeit, UV/VIS-und "P-NMR-Spektroskopie ermittelt wurde. Bei den Nickelkomplexen liegt ein losungsmittelabhangiges Gleichgewicht zwischen pentakoordiniertem NiX2L und quadratisch planarem [NiXL]+ vor. Im Falle des Pd-Komplexes [PdCI2(3 b)] (5 b) spielt sich in Methanol-Losung ein Isomerisierungsprozen an den terminalen P-Atomen ab, der wahrscheinlich auf einer reversiblen Abspaltung von HCI beruht.
Zeitschrift für Naturforschung B, 1986