Synthesis and Structures of Monomeric Divalent Germanium and Tin Compounds Containing a Bulky Diketiminato Ligand

Reaction of the β-diketiminato lithium salt Li(OEt2)[HC(CMeNAr)2] (Ar = 2,6-i-Pr2C6H3) with GeCl2·(dioxane) and SnCl2 in diethyl ether provided the monomeric complexes [HC(CMeNAr)2]MCl (M = Ge (2), Sn (3), respectively) with a three-coordinated metal center. The reductive dehalogenation reactions of 3 with C8K and LiAlH4 afforded [HC(CMeNAr)2]2Sn (7) and [HC(CMeNAr)2]AlH2, respectively. The metathesis reactions of 3 with t-BuLi, AgSO3CF3, and NaN3 resulted in the formation of [HC(CMeNAr)2]Sn(t-Bu) (4), [HC(CMeNAr)2]Sn(OSO2CF3) (5), and [HC(CMeNAr)2]SnN3 (6), respectively. Compounds 2, 3, 5, and 7 were characterized by single-crystal X-ray structural analysis. The structures indicate that the β-diketiminato backbone is essentially planar and the metal centers reside in distorted-tetrahedral environments with one vertex occupied by a lone pair of electrons. The bond angles at the metal center are in the range 85.2(8)−106.8(2)°, and the most acute angle is associated with the bite of the chelating ligand.