Alkaline Earth Metals: Organometallic ChemistryUpdate based on the original article by Jacob S. Alexander, Marites Guino‐o, Maria Felisa Zuniga, Roger C. Hahn and Karin Ruhlandt‐Senge,Encyclopedia of Inorganic ChemistrySecond Edition, © 2005, John Wiley & Sons, Ltd.

Abstract

The organometallic chemistry of the alkaline‐earth metals has undergone a renaissance during the last 20 years with heavy organoalkaline‐earth metal compounds becoming recognized as an area of organometallic chemistry with significant potential. Intense research efforts have provided a series of synthetic methodologies that provided access to a rapidly growing family of compounds not thought possible only recently. As a result, this improved insight did not only provide the basis for a more detailed understanding of the metal‐ligand bonding characteristics but also paved the way toward a number of applications including uses as diverse as in polymerization initiation, organic synthetic chemistry, catalysis, and materials chemistry. This article summarizes some of the recent, exciting developments in regards to alkaline‐earth organometallics.

bis‐Silyl‐triazenide ligands in alkaline‐earth metal chemistry

“…β-Diketiminate ligands are clearly superior for stabilizing heteroleptic complexes. [1,[3][4][5][6][7]10] For the smaller Ae metal Mg we succeeded in isolating a heteroleptic complex. The deprotonation of [(tBu 3 Si) 2 N 3 ]H by MgnBu 2 in benzene at room temperature is instantaneous.…”

“…[42] From this it can be concluded that the steric pressure of the (tBu 3 Si) 2 N 3 Scheme 2. Synthesis of the triazene proligand [(tBu 3 Si) 2 N 3 ]H and conversion into s-block metal complexes (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11).…”

“…[1][2][3] Their chelating bidentate nature, combined with considerable bulk, renders these ligands highly suitable for blocking coordination spheres of larger metals, thus stabilizing heteroleptic alkaline-earth (Ae) metal complexes. [4,5] This unique ability has especially been exploited for superbulky β-diketiminate ligands [6][7][8][9][10] and culminated in unusual Ae metal chemistry. [11][12][13] The synthetic potential of the smaller N,N-chelating NCNligands like the guanidates, [14][15][16] amidinates [17][18][19] and formamidinates [20,21] (Scheme 1a) is hitherto much less explored in s-block metal chemistry.…”