Donor–acceptor stabilized silaformyl chloride

Abstract

Formyl chloride (H(Cl)C=O) is unstable at room temperature and decomposes to HCl and CO. Silicon analogue of formyl chloride, silaformyl chloride IPr·SiH(Cl)=O·B(C(6)F(5))(3) (3) (IPr = 1,3-bis(2,6-diisopropyl-phenyl)imidazol-2-ylidene), was stabilized by Lewis donor-acceptor ligands. Compound 3 is not only the first stable acyclic silacarbonyl compound but also the first silacarbonyl halide reported so far.

An Isolable Bis(Silanone–Borane) Adduct

“…The silicon center in 3 adopts a distorted tetrahedral geometry with a short Si−O distance of 1.557(4) and 1.537(4) Å in accordance with related four‐coordinated Lewis acid stabilized silanones (1.531–1.579 Å) containing a Si=O double bond . The Si−O distance is only slightly elongated when compared with recently reported genuine silanones (1.518–1.537 Å) .…”

“…Similarly, Roesky et al. reported also the silaformyl chloride complex C , resulting from an NHC‐stabilized silylene and H 2 O⋅B(C 6 F 5 ) 3 . In 2019, the isolation of the first donor–acceptor‐supported silaaldehyde D was accomplished by the Inoue group .…”

Recent Advances in the N-Heterocyclic Carbene-Supported Chemistry of Silicon

“…Silylazides, such as Ph 3 SiN 3 , also participate in clean oxidation chemistry with 15 to give stable silylamido adducts [78] (e.g., 39; Scheme 6). A novel donor-acceptor complex featuring a silicon(IV) oxo bonding environment, IPr•SiHCl(O)•B(C 6 F 5 ) 3 (40), was prepared recently [79]. This formal silaformyl chloride complex was obtained from the condensation reaction between IPr•SiCl 2 (15) and the arylfluoroborane hydrate adduct H 2 O•B(C 6 F 5 ) 3 in toluene (Scheme 7); the HCl produced in this reaction was sequestered by IPr to form the insoluble imidazolium salt [IPrH]Cl.…”

“…Theoretical studies show that some Si-O π-bond character exists in 40; however, the extremely large polarization (96% towards Si based on NBO analysis) suggests that this bonding interaction is still considerably reduced with respect to free HClSi¼O where the Scheme 6 Representative chemistry of IPr•SiCl 2 (15); Ad ¼ adamantyl; Dipp ¼ 2,6-i Pr 2 C 6 H 3 ; Tipp¼2,4,6-i Pr 3 C 6 H 2 π-bonding component is polarized 80% towards Si. Notably, the calculated C IPr -Si bond dissociation energy in 40 was 51.1 kcal/mol (77.9 kcal/mol when corrected for dispersion effects) [79].…”

E–H Bond Activation of Ammonia and Water by a Geometrically Constrained Phosphorus(III) Compound

“…[23] Theo xidative activation of water is of immense current interest, representing ac rucial step in metal-catalyzed water splitting.D espite this fact, there are few transition-metal complexes that are able to effect this transformation. [2] Although there are several reports outlining similar reactivity at main group centers, [33][34][35][36][37][38][39][40][41] there are currently only two examples that are able to do so without the use of forcing conditions,n on-equimolar loadings of water, or secondary activating substrates. [37,41] Ther oom-temperature reaction of 3 with one equivalent of deuterium oxide results in exchange of the hydroxyl proton.…”