Phosphino[tris(trimethylsilyl)methyl]Boranes and 2,4‐Bis[tris(trimethylsilyl)methyl]‐1,3,2,4‐diphosphadiboretanes [1] |
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| Authors: | R Jetzfellner H Nöth Prof Dr R T Paine Prof Dr |
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| Institution: | 1. Munich, University, Department of Chemistry and Biochemisty;2. Munich, University, Department of Chemistry and BiochemistyDepartment Chemie, Universit?t München, Butenandtstr. 5–13, D‐81377 München, Germany;3. Department of Chemistry, University of New Mexico Albuquerque, New Mexico 87131 / USA |
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| Abstract: | The reaction of tris(trimethylsilyl)methylboron dihalides (Me3Si)3CBX2 (X = Cl, F) with the lithium phosphides LiPHtBu and LiPHmes leads to the phosphinoboranes (Me3Si)3CBX‐(PHR), (Me3Si)3CB(PHR)2 or the 1,3,2,4‐diphosphadiboretanes (Me3Si)3CB(PR)]2, depending on the ratio of the reagents, the reaction temperature and concentration. High dilution and low temperatures are required for the synthesis of (Me3Si)3CB(Hal)PHR ( 1–3 ) in order to prevent the formation of (Me3Si)3CB(PHR)2 ( 4 and 5 ). The latter compounds are best prepared in a two step phosphination from (Me3Si)3CBHal2 and LiPHR. At higher temperatures the four‐membered 1,3,2,4‐diphosphadiboretanes (Me3Si)3CB(PR)]2 6 and 7 are the most stable compounds. On the other hand, compounds of type (Me3Si)3CB(Hal)PR2, 8 and 9 , are thermally more stable than the monophosphinoboranes 1 – 3 . Phosphinoboranes of type (Me3Si)3CB(PR2)2 (R = tBu, mes) could not be prepared. NMR and mass spectral data are in accord with the monomeric nature of compounds 1 to 9 . |
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| Keywords: | Phosphinoboranes Diphosphadiboretanes Steric effects |
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