An Isolable Silicon Analogue of a Ketone that Contains an Unperturbed Si=O Double Bond

Abstract

Despite tremendous efforts to synthesize isolable compounds with an Si = Ob ond, silicon analogues of ketones that contain an unperturbed Si=Obond have remained elusive for more than 100 years.Herein, we report the synthesis of an isolable silicon analogue of ak etone that exhibits at hreecoordinate silicon center and an unperturbed Si = Obond, thus representing the first example of ag enuine silanone.M ost importantly,t his silanone does not require coordination by Lewis bases and acids and/or the introduction of electrondonating groups to stabilizethe Si=Obond. The structure and properties of this unperturbed Si=Ob ond were examined by asingle-crystal X-ray diffraction analysis,NMR spectroscopy, and theoretical calculations.B imolecular reactions revealed high electrophilicity on the Si atom and high nucleophilicity on the Oa tom of this genuine Si = Ob ond.

Bonding Relationship between Silicon and Germanium with Group 13 and Heavier Elements of Groups 14–16

“…isolated a cyclic(amino)(phosphonium‐bora‐ylide)silanone, stabilized by two different π‐donating substituents, an amino group and a more electropositive boron‐based π‐donating phosphonium boraylide functional group [85b] . Later in 2019, Iwamoto and co‐workers synthesized and isolated kinetically stabilized silicon analogue of a ketone with the unperturbed Si=O moiety, which represents the first example of isolable genuine silanone compound [85c] . The oxidation of cyclic dialkylsilylene ( 123 ) with gaseous N 2 O at room temperature led to the formation of silanone ( 124 ) in 100% yield as a white solid (Scheme 46).…”

Strained and Reactive Donor/Acceptor‐Supported Metallasilanone

“…[6] Even though some recent studies have demonstrated that bulky or/and strongly s-or/and p-donating substituents efficiently stabilize silanones, the synthesis of stable silanones I remains a great challenge and, to date, only a limited number of isolable silanones are available. [7][8][9][10][11][12] A drastic improvement in the stability was achieved by Driesss group, using donor (II) [13] or donor/acceptor (III) [14] systems. [15][16][17][18][19] Thanks to that, several stable and easy-tomanipulate silanone derivatives have been prepared.…”

“…S8 Si = 360.0. 3 : Mn-Si1 2.268(1), Si1-O1 1.592(2), O1-Mn 2.147(2), N1-Si1 1.791(2), Si1-P 2.310(1), Mn-C (average) 1.820, C-O (average) 1.142, O1-Si1-Mn 64.85(8), Si1-O1-Mn 72.99(8), O1-Mn-Si1 42.16(6), N1-Si1-P 89.90(8), N1-Si1-Mn 133.72( 9), Mn-Si1-P 132.77(4), Si1-Mn-C3 90.58 (10), Si1-Mn-C4 87.26 (11), Si1-Mn-C5 143.61 (11), Si1-Mn-C6 118.19 (13), C3-Mn-C4 174.84( 16), C5-Mn-C6 98.19 (17). (S8 Si(N,P,Mn) = 356.39).…”

Synthesis of a Stable N‐Hetero‐RhI‐Metallacyclic Silanone

“…Indeed, although the recent studies demonstrated that bulky or/and strongly s-or/and p-donating substituents efficiently stabilize silanones I-V enough to be isolated in the crystalline form, [10][11][12][13][14] most of them remain unstable in solution at room temperature. To the best of our knowledge, only two silanones, such as the chromium-substituted cationic silanone I [10] and cyclic dialkylsilanone V, [14] are stable in solution at RT. However, even silanone V, protected by extremely bulky substituents, dimerizes above 60 8C.…”

“…This spectral pattern, showing a large transcoupling constant ( 2 J PA-PB = 324.4 Hz) and two small ciscoupling constants ( 2 J PA-PC = 26.0 Hz and 2 J PB-PC = 23.7 Hz), is typical for square planar Rh I complexes, suggesting a classical geometry around the Rh I -center in 2, instead of the unusual distorted tetrahedral geometry observed for silylene 1. [18] The molecular structure of silanone 2 [19] reveals a planar geometry around the three-coordinated silicon atom (S si 8 = 358.398) and a short Si=O bond length [1.540 (3) ] which is longer than those of chromium-substituted silanone I (1.526 ) [10] and of dialkylsilanone V (1.518 ) [14] but is similar to those observed for other p-donor substituted silanones II-IV (1.533-1.543 ). [11][12][13] The N1-Si1 bond length [1.775 3] is almost identical to that of silylene 1 (1.771-1.781 ).…”