Disproportionation and Ligand Lability in Low Oxidation State Boryl-Tin Chemistry.

ABSTRACT: Boryltin compounds featuring the metal in the+1 or 0 oxidation states can be synthesized from the carbene-stabilized tin(II) bromide (boryl)Sn(NHC)Br (boryl={B(NDippCH)₂ }; NHC=C{(Nⁱ PrCMe)₂ }) by the use of strong reducing agents. The formation of the mono-carbene stabilized distannyne and donor-free distannide systems (boryl)SnSn(IPrMe)(boryl) (2) and K₂ [Sn₂ (boryl)₂ ] (3), using Mg(I) and K reducing agents mirrors related germanium chemistry. In contrast to their lighter congeners, however, systems of the type [Sn(boryl)]_n are unstable with respect to disproportionation. Carbene abstraction from 2 using BPh₃ , and two-electron oxidation of 3 both result in the formation of a 2 : 1 mixture of the Sn(II) compound Sn(boryl)₂ , and the hexatin cluster, Sn₆ (boryl)₄ (4). A viable mechanism for this rearrangement is shown by quantum chemical studies to involve a vinylidene intermediate (analogous to the isolable germanium compound, (boryl)₂ Ge=Ge), which undergoes facile atom transfer to generate Sn(boryl)₂ and trinuclear [Sn₃ (boryl)₂ ]. The latter then dimerizes to give the observed hexametallic product 4, with independent studies showing that similar trigermanium species aggregate in analogous fashion.

SUBMITTER: Zheng X 

PROVIDER: S-EPMC10947314 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature