Effect of the Lead(II) Bond Angle on the Reactivity of Diaminoplumbylenes toward Ammonia: From Inertness to Immediate Ammonolysis
Robin Guthardt, Clemens Bruhn, Christian Färber, Ulrich Siemeling
Abstract
The reactivity of the N-heterocyclic plumbylenes o-C6H4(NSiRMe2)2Pb (R = Me, t-Bu), nap(NSiRMe2)2Pb (nap = naphthalene-1,8-diyl; R = Me, t-Bu), and [Fe{(η5-C5H4)NSit-BuMe2}2Pb] as well as of the acyclic diaminoplumbylene [(Me3Si)2N]2Pb toward ammonia depends critically on the N–Pb–N bond angle. The five-membered-ring congeners have the smallest angles (ca. 78°) and are inert toward NH3. The acyclic and the ferrocene-based congeners exhibit the largest PbII bond angles (ca. 104 and 99°, respectively) and undergo immediate ammonolysis. The naphthalene-based six-membered-ring congeners have intermediate bond angles (ca. 83°) and show significantly slower ammonolysis, which allowed the isolation of the reactive intermediate [Pb(μ-NH2){nap(NSiMe3)(NHSiMe3)}]2 at low temperatures. The plumbylenes of this study which undergo ammonolysis also react readily with aniline.