Synthesis of an N‐Heterocylic Boryl‐Stabilized Disilyne and Its Application to the Activation of Dihydrogen and C−H Bonds

Abstract

AbstractThe synthesis of low‐valent silicon compounds that enable the activation of small molecules has been of great current interest. Reduction of N‐heterocyclic boryltribromosilane (NHB)SiBr3 (2, NHB=[ArN(CMe)2NAr]B, Ar=2,6‐iPr2C6H3) with three equiv. of lithium in diethyl ether yielded the NHB‐stabilized disilyne (NHB)Si≡Si(NHB) (3). Disilyne 3 slowly reacted with toluene, leading to the activation of one benzylic C−H bond and one C=C double bond with the formation of 4. Treatment of 3 with dihydrogen under 1 atm at room temperature resulted in the exclusive formation of the first boryl‐stabilized 1,2‐dihydrodisilene. Compounds 3–5 have been characterized by single‐crystal X‐ray diffraction studies, which indicated the co‐planarity of the B−Si−Si−B plane with the NHB rings in compounds 3 and 5. DFT calculations indicated the significant π electron delocalization of the Si−Si multiple bonds to the B−N bonds in NHB rings.