Molecular Zinc Hydride Cations [ZnH]+: Synthesis, Structure, and CO2 Hydrosilylation Catalysis.

Molecular Zinc Hydride Cations [ZnH]+: Synthesis, Structure, and CO2 Hydrosilylation Catalysis.
Angew Chem Int Ed Engl. 2020 Sep 15;:
Authors: Okuda J, Ritter F, Spaniol TP, Douair I, Maron L
Abstract
Protonolysis of thermally unstable and insoluble [ZnH2]n with the conjugated Brønsted acid of the bidentate diamine TMEDA (N,N,N',N'-tetramethylethane-1,2-diamine) and TEEDA (N,N,N',N'-tetraethylethane-1,2-diamine) gave the zinc hydride cation [(L2)ZnH]+, isolable either as the mononuclear THF adduct [(L2)ZnH(thf)]+[BArF4]- (L2 = TMEDA; BArF4- = [B(3,5-(CF3)2-C6H3)4]-) or as the dimer [{(L2)Zn)}2(μ-H)2]2+[BArF4]-2 (L2 = TEEDA). In contrast to [ZnH2]n, the cationic zinc hydrides are thermally stable and soluble in THF. [(L2)ZnH]+ was also shown to form di- and trinuclear adducts of the elusive neutral [(L2)ZnH2] containing both terminal and bridging hydrido ligands. All hydride-containing cations readily inserted CO2 to give the corresponding formate complexes. [(TMEDA)ZnH]+[BArF4]- catalyzed the hydrosilylation of CO2 with tertiary hydrosilanes to give stepwise formoxy silane, methyl formate, and methoxy silane. The unexpected formation of methyl formate was shown to result from the zinc-catalyzed transesterification of methoxy silane with formoxy silane, which was eventually converted into methoxy silane as well.
PMID: 32931656 [PubMed - as supplied by publisher]

Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Okuda J, Ritter F, Spaniol TP, Douair I, Maron L Tags: Angew Chem Int Ed Engl Source Type: research