Hydridotetrylene [Ar*EH] (E = Ge, Sn, Pb) coordination at tantalum, tungsten, and zirconium

In a reaction of tantalocene trihydride with the low valent aryl tin cation [Ar*Sn(C6H6)][Al(OC{CF3}(3))(4)] (1a) the hydridostannylene complex [Cp2TaH2-Sn(H)Ar*][Al(OC{CF3}(3))(4)] (2) was synthesized. Hydride bridged adducts [Cp2WH2EAr*][Al(OC{CF3}(3))(4)] (E = Sn 3a, Pb 3b) were isolated as products of the reaction between Cp2WH2 and cations [Ar*E(C6H6)][Al(OC{CF3}(3))(4)] (E = Sn 1a, Pb 1b). The tin adduct 3a exhibits a proton migration to give the hydridostannylene complex [Cp2W(H)=Sn(H)Ar*HAE(OC{CF3}(3))(4)] 4a. The cationic complex 4a is deprotonated at the tin atom in reaction with base me (NHC)-N-Me at 80 degrees C to give a hydrido-tungstenostannylene [Cp2W(H)SnAr*] 5a. Reprotonation of metallostannylene 5a with acid [H(Et2O)(2)][BArF] provides an alternative route to hydridotetrylene coordination. Complex 4a adds hydride to give the dihydrostannyl complex [Cp2W(H)-SnH2Ar*] (7). With styrene 4a shows formation of a hydrostannylation product [Cp2W(H)=Sn(CH2CH2Ph)Ar*][Al(OC{CF3}(3))(4)] (8). The lead adduct 3b was deprotonated with m (NHC)-N-Me to give plumbylene 5b [Cp2W(H)PbAr*]. Protonation of 5b with [H(Et2O)(2)] [Al(OC{CF3}(3))(4)] at -40 degrees C followed by low temperature NMR spectroscopy indicates a hydridoplumbylene intermediate [Cp2W(H)=Pb(H)Ar*](+) (4b). Hydrido-tungstenotetrylenes of elements Ge (5c), Sn (5a) and Pb (5b) were also synthesized reacting the salt [Cp2W(H)Li](4) with organotetrylene halides. The metallogermylene [Cp2W(H)GeAr*] (5c) shows an isomerization via 1,2-H-migration to give the hydridogermylene [Cp2W=Ge(H)Ar*] (9), which is accelerated by addition of AIBN. 9 is at rt photochemically transferred back to 5c under light of a mercury vapor lamp. Zirconocene dihydride [Cp2ZrH2](2) reacts with tin cation la to give the trinuclear hydridostannylene adduct 10 [({Cp2Zr}(2){mu-H})(mu-H)(2)R-Sn(H)Ar*][Al(OC{CF3}(3))(4)]. Deprotonation of 10 was carried out using benzyl potassium to give neutral [[{Cp2Zr}(2){mu-H})(mu-H)mu-Sn(H)Ar*] (11). 11 was also obtained from the reaction of low valent tin hydride [Ar*SnH](2) with two equivalents of [Cp2ZrH2](2). The trihydride Ar*SnH3 reacts with half of an equivalent of [Cp(2)ZrH2](2) under evolution of hydrogen and formation of a dihydrostannyl complex 13 [Cp2Zr(mu-H)SnH2Ar*](2) and with further equivalents of Ar*SnH3 to give bis(hydridostannylene) complex [Cp2Zr{Sn(H)Ar*}(2)].

Automated summary

Hydridostannylene complexes and related complexes have been successfully synthesized under different reaction conditions, which are of significance for studying transition metal catalyzed reactions.