ISSN:
0009-2940
Keywords:
1,3,2,4-Diphosphadisiletanes
;
Hindered rotation of aryl group
;
Inversion at phosphorus
;
Silanes, diorganodi(phosphino)- and fluoro-diorgano(phosphino)
;
Chromium complexes
;
Tungsten complexes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Reaction of the bulkily substituted dichlorodiorganosilanes R1R2SiCl2 (R1 = Mesityl, R2 = Mesityl, tBu, OtBu, Xylyl, iBu) with LiPH2. dme in a 1 : 2 molar ratio in THF at -30°C leads to the new organo-substituted 1,3,2,4-diphosphadisiletanes 1a - e. Compounds 1c - e are isolated as mixtures of diastereomers. The crowded dichlorosilane Is(tBu)SiCl2 (Is = 2,4,6- triisopropylphenyl) reacts with LiPH2. dme above 10°C to yield the disubstituted products Is(tBu)Si(PH2)2 (2f) in 87% yield and only minor amounts of the corresponding four-membered ring [Is(tBu)SiPH]2 (1f), detected by 31P- and 29Si-NMR spectroscopy. Treatment of 2f with 2 equivalents of nBuLi in Et2O gives Is(tBu)Si(PHLi)2 (3f), which with Is(tBu)SiCl2 forms 1f. The reaction of difluorodiisitylsilane with LiPH2.dme in THF leads to different products, depending on the reaction temperature. At - 30°C Is2Si(PHLi)F (7g) is obtained as sole product, whereas at 28°C the air-stable diphosphino-substituted Is2Si(PH2)2 (2g) is formed. Elimination of LiF from 7g affords the tetraisityl-substituted P2Si2-cyclobutane 1g, and treatment with H2O and Me3SiCl leads to Is2Si(PH2)F (8g) and Is2Si(PHSiMe3)F (9g). The temperature-dependent 1H-NMR spectra of 1a - g exhibit two dynamic processes: hindered rotation of the aryl groups at silicon and inversion at phosphorus. - The solid state structures of 1a, 1b, 1g, and 2g are established by X-ray crystallography. Reaction of 1a with 2 equivalents of M(CO)5.thf (M = Cr, W) yields the P,P′-bis(pentacarbonylmetal) complexes 10a (M = Cr) and 11a (M = W). A single-crystal X-ray diffraction analysis of 10a is performed.Concerning New 1,3,2,4-Diphosphadisiletanes and Diorganodi(phosphino)silane Derivatives
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19911240908
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