Bildung siliciumhaltiger Verbindungen, XXVII. Carbosilane mit vier Si‐Atomen

Abstract

Es werden Carbosilane mit vier Si‐Atomen isoliert und ihre Reaktionen untersucht. Aus den Pyrolyseprodukten von CH3SiCl3 wurde 2,2,4,4,6,6,8,8,‐octachlor‐2,4,6,8‐tetrasilabicyclo[3.3.0]oct‐1(5)en (1) isoliert. Es bildet mit CH3MgJ 2,2,4,4,6 6 8 8‐octamethyl‐2 4 6 8‐tetrasilabicyclo[3.3.0]oct‐1(5)en (2), das mit Brom zu 1,5‐dibrom‐2,2,4,4,6,6,8,8‐octamethyl‐2,4,6,8‐tetrasilabicyclo[3.3.0]octan (3) reagiert. Mit LiAlH4 wird aus (3) Verbindung (2) zurückgebildet. (3) spaltet um 130°C zu (2) und Br(CH3)2SiCH2Si(CH3)2CCSi(CH3)2CH2Si(CH3)2Br (4). Aus dem Umsetzungsprodukt von CH2Cl2 mit Silicium wurde [SiCl2CH2]4 (5) isoliert, deren SiCl Gruppen mit CH3MgJ zu [Si(CH3)2CH2]4 (6) reagieren, mit LiAlH4 die Verbindung [SiH2CH2]4 (7) bilden. Das zu Verbindung (5) isomere 1‐trichlorsilymethylen‐1,3,3,5,5‐pentachlor‐1,3,5‐trisilacyclohexan (8) tritt zusammen mit (5) auf. (8) bildet mit LiAlH4 das 1‐silylmethylen‐1,3,5‐trisilacyclohexan (9). Es werden die PMR‐Spektren der Verbindungen angegeben. Zu den Verbindungen vgl. noch Tab. 1 im Text.

Phosphine-Catalyzed Si−C Coupling of Bissilylmethanes: Preparation of Cyclic (Cl2SiCH2)2 and Linear Cl2Si(CH2SiCl3)2 via Silylene and Silene Intermediates

“…Either cyclic (2) or linear (3) carbosilane was produced depending on the second addition of the silene intermediates. From a series of Si-C coupling reactions with bissilylmethanes (7)(8)(9), there appeared to be a general substituent effect, where a chlorine substituent at the silicon atom was found to be most effective.…”

“…Later, Fritz, and Matern 7 examined the same reaction using a fluidized-bed reactor at 320 °C and isolated more than 40 carbosilanes ranging from one to 12 silicon atoms, including six-and eight-membered cyclic carbosilanes, (Cl 2 SiCH 2 ) 3 8 and (Cl 2 SiCH 2 ) 4 . 9 Although the reactions were carried out on a large scale using a continuous process, the yields of distillable products were only ∼20%, partly due to the decomposition of methylene chloride. Methylene chloride degradation caused carbon deposition on the surfaces of the elemental silicon and copper catalyst, which deactivated the solid reactants.…”

Adamantane-type clusters: compounds with a ubiquitous architecture but a wide variety of compositions and unexpected materials properties

“…Please do not adjust margins Please do not adjust margins Please do not adjust margins (2,6-dimethoxyphenyl)K, CaI2 / THF, 3 days K [30] [Fe4(Ph)6(THF)4] ( 28) Fe(acac)3, PhMgBr / THF, -30 °C, 25 min C [31] [Fe4(p-tolyl)6(THF)4] ( 29) Fe(acac)3, p-tolylMgBr / THF, -30 °C, 25 min C [31] [Fe4(p-tolyl)6(THF)3] ( 30) Fe(acac)3, p-tolylMgBr / THF, -30 °C, 25 min C [31] [Fe4(4-F-Ph)6(THF)4] ( 31) Fe(acac)3, 4-F-PhMgBr / THF, -30 °C, 25 min C [31] [BMIm]2[{Fe(CO)3}4Sn6I10] ( 32 Ni(COMe)Cl(PMe3)2, PMe3, Tl[BF4] / CH2Cl2, RT, 30 min C [34] [(NiPMe3)4(CO)6] (36) bis(cod)nickel, PMe3, CO / toluene, RT, 6h F [35] [(NiP n Bu3)4(CO)6] (37) bis(cod)nickel, P n Bu3, CO / toluene, RT, 6h F [35] [(PdP n Bu3)4(CO)6] (38) Pd4(CO)5(PBu n 3)4, CH3COOH / EtOH, Pentane, RT, 2 days or Pd(OAc)2, CH3COOH, CO, PBu n 3 / dioxane, Me2CO, 5 days J/F [36] cod 39). [37][38][39][40] In subsequent work, access to such compounds was made at considerably lower temperatures and in higher yields. [(SiMe)4(CH2)6] (40, Figure 4) could be obtained from an AlBr3 induced rearrangement of (Me2SiCH2)3 at 100 °C, which could then in turn be reacted with Cl2 and I2 to form 39 or be treated with Li[AlH4] to form the hydrogen terminated [(SiH)4(CH2)6] (41).…”

“…[(SiMe)4(CH2)6] (40, Figure 4) could be obtained from an AlBr3 induced rearrangement of (Me2SiCH2)3 at 100 °C, which could then in turn be reacted with Cl2 and I2 to form 39 or be treated with Li[AlH4] to form the hydrogen terminated [(SiH)4(CH2)6] (41). [39,41,42] Via both of these routes, tetrasilaadamantanes with mixed methyl and halide positions can be isolated as well. [41][42][43] These clusters described so far are used as the basis for ligand exchange reactions at the Si sites (method Q, leading to 42-55), often by exchanging the halides found in various positions.…”

“…[52] It was also possible to obtain the corresponding stannasilaadamantanes [(SiSiCl3)4(SnMe2)6-x(SiCl2)x] ((88-89, x = 1-2) by substituting the Ge component for the higher homolog Me2SnCl2 in the reaction. [37,39,42] [(SiMe)4(CH2)6] (40) SiMe4 / 700 °C or (Me2SiCH2)3, AlBr3 / 100 °C A [38,40,41] [(SiH)4(CH2)6] (41) Li[AlH4], [(SiMe)4(CH2)6] (40) Q [39] [(SiMe)3SiBr(CH2)6] (42) (Me2SiCH2)3, AlBr3 / 100 °C J [41,43] [(SiMe)2(SiBr)2(CH2)6] (43) (Me2SiCH2)3, AlBr3 / 100 °C J [41] [(SiMe)3SiCl(CH2)6] (44) (Me2SiCH2)3, AlCl3 / 100 °C J [41] [(SiMe)2(SiCl)2(CH2)6] (45) (Me2SiCH2)3, AlCl3 / 100 °C J [41] [SiMe(SiCl)3(CH2)6] ( 46)…”