language: en

DOI: 10.1002/zaac.200700543

Synthesis and X-ray Structures of the Polycyclic Dimers {[PhB(μ-NtBu) 2 AsN(tBu)H]LiI} 2 and [PhB(μ-NtBu) 2 AsN(tBu)Li] 2

Jari Konu and Tristram Chivers*
Calgary AB / Canada,
University of Calgary, Department of Chemistry

[Received October 5 th , 2007; accepted December 15 th , 2007.]

Abstract. The metathesis of [PhB(μ-NtBu) 2 ]AsCl and tBuN(H)Li in 1:1 molar ratio in diethyl ether produced the amido derivative [PhB(μ-NtBu) 2 AsN(tBu)H] (1) in good yield. The lithiation of 1 with one equivalent of nBuLi afforded the lithium salt [PhB(μ-NtBu) 2 AsN(tBu)Li] (2a). Both 1 and 2a were characterized by multinuclear NMR spectroscopy. The crystal structure of 2a is comprised of a U-shaped, centrosymmetric dimer in which the monomeric [PhB(μ-NtBu) 2 AsN(tBu)] 񮽙 Li 񮽙 units are linked by Li-N interactions to give a six-rung ladder. Oxidation of 2a with one-half equivalent of I 2 in diethyl ether resulted in hydrogen abstraction from the solvent to give the dimeric lithium iodide adduct {[PhB(μ-NtBu) 2 AsN(tBu)H]LiI} 2 (1 · LiI) with a central Li 2 I 2 ring.

Keywords: Arsenic; Boraamidinate; Lithium; Polycyclic compounds; Crystal structures Introduction