The electronic structure of a β-diketiminate manganese hydride dimer

Abstract

The absence of a metal–metal multiple bond in a dimeric manganese hydride catalyst supported by β-diketiminate ligands, [(2,6-iPr2PhBDI) Mn(μ-H)]2, was investigated with density functional theory in conjunction with experimental evidence.

Synthesis of Aminosilane Chemical Vapor Deposition Precursors and Polycarbosilazanes through Manganese-Catalyzed Si–N Dehydrocoupling

“…Finally, when 2 equiv of isopropylamine ( 1f ) was added to 1 , complete conversion to the amido dimer [( 2,6‑ i Pr2Ph BDI)­Mn­(μ-NH i Pr)] 2 ( 2 , Figure a) was observed after 24 h. This complex was found to exhibit paramagnetically broadened 1 H NMR resonances over a 35 ppm range, and its magnetic susceptibility of 6.3 μ B (25 °C) is consistent with the presence of high-spin Mn­(II) and the value of 6.5 μ B (25 °C) reported for imino­(amido) dimer [( 2,6‑ i Pr2Ph BDI)­Mn­(μ-NCHPh)] 2 . The solid-state structure of 2 (Figure b) revealed a pseudo-tetrahedral coordination environment around each metal center and a Mn–Mn distance of 3.0487(6) Å, indicative of a weak Mn–Mn bonding interaction . One hydrogen atom on each bridging amido ligand was located in the difference map, confirming that these ligands are monoanionic and that the Mn centers of 2 are divalent.…”

“…In 2018, we reported the synthesis, hydrosilylation activity, and silicone curing ability of the β-diketiminate manganese hydride dimer [( 2,6‑ i Pr2Ph BDI)­Mn­(μ-H)] 2 ( 1 , Figure f) . This catalyst has also been found to mediate the hydroboration of nitriles to generate diborylamines, and an electronic structure investigation revealed that 1 easily dissociates into monomers to enable catalysis . In this study, we demonstrate that 1 is active for the dehydrogenative coupling of amines to the widely utilized industrial gas SiH 4 .…”

“…37 This catalyst has also been found to mediate the hydroboration of nitriles to generate diborylamines, 38 and an electronic structure investigation revealed that 1 easily dissociates into monomers to enable catalysis. 39 In this study, we demonstrate that 1 is active for the dehydrogenative coupling of amines to the widely utilized industrial gas SiH 4 . In the patent literature, the halogen-free preparation of aminosilane CVD precursors is known to proceed upon heating amines with SiH 4 to 125 °C in the presence of Ru/C; 40 however, this remains the only mention of commercial aminosilane CVD precursor synthesis by way of catalytic Si−N dehydrocoupling.…”

“…38 The solid-state structure of 2 (Figure 4b) revealed a pseudotetrahedral coordination environment around each metal center and a Mn−Mn distance of 3.0487(6) Å, indicative of a weak Mn−Mn bonding interaction. 39 One hydrogen atom on each bridging amido ligand was located in the difference map, confirming that these ligands are monoanionic and that the Mn centers of 2 are divalent.…”

Sustainable preparation of aminosilane monomers, oligomers, and polymers through Si–N dehydrocoupling catalysis

“…35, 38 ) in 2018. 109 This catalyst, which features weak antiferromagnetic coupling between its manganese centres, 110 has been found to catalyse the hydrosilylation of olefins to cure silicones, 109 and the dihydroboration of nitriles. 111 Notably, when exploring the scope of 38 -based olefin hydrosilylation, we observed that 4-aminostyrene addition to 38 resulted in the evolution of gas (presumably H 2 ) and that subsequent addition of PhSiH 3 led to polymer formation (presumably via amine silylation and olefin hydrosilylation).…”