Synthesis of Cobalt-Tin and -Lead Tetrylidynes-Reactivity Study of the Triple Bond

Angew Chem Int Ed Engl. 2023 Aug 28;62(35):e202305951. doi: 10.1002/anie.202305951. Epub 2023 Jul 21.

Abstract

Tetrylidynes [TbbSn≡Co(PMe3 )3 ] (1 a) and [TbbPb≡Co(PMe3 )3 ] (2) (Tbb=2,6-[CH(SiMe3 )2 ]2 -4-(t-Bu)C6 H2 ) are accessed for the first time via a substitution reaction between [Na(OEt2 )][Co(PMe3 )4 ] and [Li(thf)2 ][TbbEBr2 ] (E=Sn, Pb). Following an alternative procedure the stannylidyne [Ar*Sn≡Co(PMe3 )3 ] (1 b) was synthesized by hydrogen atom abstraction using AIBN from the paramagnetic hydride complex [Ar*SnH=Co(PMe3 )3 ] (4) (AIBN=azobis(isobutyronitrile)). The stannylidyne 1 a adds two equivalents of water to yield the dihydroxide [TbbSn(OH)2 CoH2 (PMe3 )3 ] (5). In reaction of the stannylidyne 1 a with CO2 a product of a redox reaction [TbbSn(CO3 )Co(CO)(PMe3 )3 ] (6) was isolated. Protonation of the tetrylidynes occurs at the cobalt atom to give the metalla-stanna vinyl cation [TbbSn=CoH(PMe3 )3 ][BArF 4 ] (7 a) [ArF =C6 H3 -3,5-(CF3 )2 ]. The analogous germanium and tin cations [Ar*E=CoH(PMe3 )3 ][BArF 4 ] (E=Ge 9, Sn 7 b) (Ar*=C6 H3 (2,6-Trip)2 , Trip=2,4,6-C6 H2 iPr3 ) were also obtained by oxidation of the paramagnetic complexes [Ar*EH=Co(PMe3 )3 ] (E=Ge 3, Sn 4), which were synthesized by substitution of a PMe3 ligand of [Co(PMe3 )4 ] by a hydridoylene (Ar*EH) unit.

Keywords: Cobalt; Lead; Tetrylidyne; Tin; Triple Bond.