Transmetallation vs adduct: Diverse reactivity of N,O-ketiminato germylene with [Cp*MCl2]2 (M = Rh or Ir; Cp* = η5-C5Me5) and MCl5 (M = Nb and Ta)

Tridentate NacNac Stabilized Tin and Nickel Complexes: Access to a Monomeric Nickel Hydride and Its Catalytic Application

The transmetalation reaction of picolyl-supported tridentate nacnac germylene monochloride [2,6-iPr₂-C₆H₃NC(Me)CHC(Me)NH(CH₂py)]GeCl (1) (py = pyridine) with SnCl₂ results in an analogous stannylene chloride (2). The three-coordinated stannylenium cation [{2,6-iPr₂-C₆H₃NC(Me)CHC(Me)NH(CH₂py)}Sn]⁺ with SnCl₃^- as a counteranion (3) has been generated through the abstraction of chloride ligand from 2 using an additional equivalent of SnCl₂. Instead of forming a donor-acceptor complex, 2 undergoes a facile redox transmetalation reaction with Ni(COD)₂ (COD = cyclooctadiene) and CuCl to afford analogous nickel and copper complexes [2,6-iPr₂-C₆H₃NC(Me)CHC(Me)NH(CH₂py)]MCl [M = Ni (4) and Cu (5)]. The reactions of 4 with potassium tri-sec-butylborohydride (commonly known as K-selectride) and AgSbF₆ provide access to monomeric Ni(II) hydride, [2,6-iPr₂-C₆H₃NC(Me)CHC(Me)NH(CH₂py)]NiH (6) and a Ni(II) cation, [{2,6-iPr₂-C₆H₃NC(Me)CHC(Me)NH(CH₂py)}Ni][SbF₆] (7), respectively. 6 was found to be an effective catalyst for the hydroboration of amides.

Access to diverse germylenes and a six-membered dialane with a flexible β-diketiminate

A nacnac-based tridentate ligand containing a picolyl group (L) was employed to isolate chlorogermylene (1). The reaction of 1 with another equivalent of GeCl2·dioxane surprisingly gave pyridylpyrrolide-based chlorogermylene (2) via C-N bond cleavage and C-C coupling, while with AlCl3, it afforded a transmetalated product, 4. The reaction of L with AlH3·NMe2Et led to an unusual cyclohexane type six-membered dialane heterocycle (5).