Disilicon Dicarbonyl Complex: Synthesis and Protonation of CO with O–H Bond

Abstract

Reaction of solid NHB-stabilized disilyne (NHB)Si�Si(NHB) (1, NHB = [ArN(CMe) 2 NAr]B, Ar = 2,6-iPr 2 C 6 H 3 ) with 1 atm of carbon monoxide yielded the first 1,2-disilicon dicarbonyl complex (NHB)(OC)SiSi(CO)(NHB) (2). Hydrolysis and methanolysis of 2 led to the C−C coupling and protonation of two CO oxygen atoms giving disilacyclobutene derivatives 3 and 4. In contrast, reaction of 2 with iodomethane resulted in the oxidative addition to the silicon atoms with the formation of 1,2-diiododisilane 5 with the liberation of CO molecules. Single-crystal X-ray diffraction analysis of 2 disclosed the coordination of CO to the two silicon atoms with a unique 1,2-dicarbonyl-disilane skeleton, in which the pronounced backbonding from the lone pairs of silicon p orbitals to CO π* orbitals was elucidated by DFT calculations.

Recent advances in the chemistry of isolable carbene analogues with group 13–15 elements

“…Simultaneously, Inoue reported the silicon-carbonyl complexes 65 , underscoring the potential of disilylsilylene in CO coordination. 239 Moreover, in 2022, Cui introduced the disilicon dicarbonyl complex 66 , which enables the protonation of CO. 240 These discoveries show that the strong σ-donating boryl, 241 silyl and gallyl substituents play a vital role in the reactivity of the silylenes. In compound 64 , the C–Si bond length is reported to be 1.865 Å, which is indicative of a Si–C single bond.…”

Boryl-substituted low-valent heavy group 14 compounds

“…In 2022, Cui and co-workers reported on the reaction of an NHB-substituted disilyne with CO. 71 Previous studies had suggested that the stability of transition metal carbonyl compounds is primarily attributed to the back-donation of d electrons into the π* orbitals of CO. Main group elements, due to the lack of d-valence electrons, are typically reluctant to generate stable carbonyl complexes under standard conditions. However, when a solid sample of disilyne 43 was exposed to CO at room temperature, it led to the formation of the unusual disilene dicarbonyl compound (NHB)(CO)Si–Si(CO)(NHB) 79 (Scheme 45).…”

Applications of low-valent compounds with heavy group-14 elements

“…The strong back-bonding interactions from the n(Si) to π*(CO) orbitals were revealed by both DFT calculations and single-crystal X-ray diffraction investigations. 208…”

“…The strong back-bonding interactions from the n(Si) to p*(CO) orbitals were revealed by both DFT calculations and single-crystal X-ray diffraction investigations. 208 3.3.5 H 2 3.3.5a Low-valent silicon species. In many homogeneous catalytic processes, including the hydrogenation of unsaturated chemical molecules and hydroformylation reactions, the cleavage of dihydrogen is an essential step.…”