Syntheses and Crystal Structures of Novel Functionalized Lithium Silylamides R(4–n)Si(N(Li)CH2CH2NR'2)n (R = Me, Ph, R' = Me, iPr; n = 2, 3)1. Issue 14 (18th October 2013)

• Record Type: Journal Article
• Authors: Lechner, Bob‐Dan; Hahn, Sven; Wagner, Christoph; Merzweiler, Kurt
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 639:Issue 14(2013)
• Page Start: 2597
• Page End: 2603
• Publication Date: 2013-10-18
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.201300372
• Languages: English
• ISSNs: 0044-2313

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The difunctional aminosilanes Ph<sub>2</sub>Si(NHCH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>)<sub>2</sub> (<bold>1</bold>), Me<sub>2</sub>Si(NHCH<sub>2</sub>CH<sub>2</sub>N<italic>i</italic>Pr<sub>2</sub>)<sub>2</sub> (<bold>2</bold>) and Ph<sub>2</sub>Si(NHCH<sub>2</sub>CH<sub>2</sub>N<italic>i</italic>Pr<sub>2</sub>)<sub>2</sub> (<bold>3</bold>) were prepared by aminolysis of the chlorosilanes R<sub>2</sub>SiCl<sub>2</sub> (R = Ph, Me) and the corresponding ethylenediamine derivatives H<sub>2</sub>NCH<sub>2</sub>CH<sub>2</sub>NR'<sub>2</sub> (R' = Me, <italic>i</italic>Pr). The trifunctional aminosilane MeSi(NHCH<sub>2</sub>CH<sub>2</sub>N<italic>i</italic>Pr<sub>2</sub>)<sub>3</sub> (<bold>4</bold>) was synthesized from MeSiCl<sub>3</sub> and H<sub>2</sub>NCH<sub>2</sub>CH<sub>2</sub>N<italic>i</italic>Pr<sub>2</sub> in the presence of triethylamine as auxiliary base. Compounds <bold>1–4</bold> were obtained as pale yellow viscous oils that have been characterized by <sup>1</sup>H, <sup>13</sup>C and <sup>29</sup>Si NMR spectroscopy. Treatment of the aminosilanes <bold>1–3</bold> with two equivalents and <bold>4</bold> with three equivalents of <italic>n</italic>BuLi in hexane led to the corresponding lithium salts, which were recrystallized from <italic>n</italic>‐hexane at –25 °C. The crystal structure analysis of Ph<sub>2</sub>Si(N(Li)CH<sub>2</sub>CH<sub>2</sub>NMe<sub>2</sub>)<sub>2</sub> (<bold>5</bold>) and Me<sub>2</sub>Si(N(Li)CH<sub>2</sub>CH<sub>2</sub>N<italic>i</italic>Pr<sub>2</sub>)<sub>2</sub> (<bold>6</bold>) revealed dimeric molecules which contain a central Li<sub>4</sub>N<sub>4</sub> heterocubane core. Additionally, the lithium atoms are coordinated intramolecularly by NR<sub>2</sub> donor groups. For Ph<sub>2</sub>Si(N(Li)CH<sub>2</sub>CH<sub>2</sub>N<italic>i</italic>Pr<sub>2</sub>)<sub>2</sub> (<bold>7</bold>) dimers with Si<sub>2</sub>N<sub>4</sub>Li<sub>4</sub> adamantane core were observed. MeSi(N(Li)CH<sub>2</sub>CH<sub>2</sub>N<italic>i</italic>Pr<sub>2</sub>)<sub>3</sub> (<bold>8</bold>) displays dimers with a rhombododecahedral Si<sub>2</sub>N<sub>6</sub>Li<sub>6</sub> core. Like in compounds <bold>5–7</bold> the cluster structure is supported by intramolecular coordination of the N<italic>i</italic>Pr<sub>2</sub> donor group.</p> </abstract>