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(C(6)H(6))][Al(OC{CF(3)}(3))(4)] (1a) the hydridostannylene complex [Cp(2)TaH(2)–Sn(H)Ar*][Al(OC{CF(3)}(3))(4)] (2) was synthesized. Hydride bridged adducts [Cp(2)WH(2)EAr*][Al(OC{CF(3)}(3))(4)] (E = Sn 3a, Pb 3b) were isolated as products of the reaction between Cp(2)WH(2) and cations [Ar*E(C(6)H(6))][Al(OC{CF(3)}(3))(4)] (E = Sn 1a, Pb 1b). The tin adduct 3a exhibits a proton migration to give the hydridostannylene complex [Cp(2)W(H)[double bond, length as m-dash]Sn(H)Ar*][Al(OC{CF(3)}(3))(4)] 4a. The cationic complex 4a is deprotonated at the tin atom in reaction with base (Me)NHC at 80 °C to give a hydrido-tungstenostannylene [Cp(2)W(H)SnAr*] 5a. Reprotonation of metallostannylene 5a with acid [H(Et(2)O)(2)][BAr(F)] provides an alternative route to hydridotetrylene coordination. Complex 4a adds hydride to give the dihydrostannyl complex [Cp(2)W(H)–SnH(2)Ar*] (7). With styrene 4a shows formation of a hydrostannylation product [Cp(2)W(H)[double bond, length as m-dash]Sn(CH(2)CH(2)Ph)Ar*][Al(OC{CF(3)}(3))(4)] (8). The lead adduct 3b was deprotonated with (Me)NHC to give plumbylene 5b [Cp(2)W(H)PbAr*]. Protonation of 5b with [H(Et(2)O)(2)][Al(OC{CF(3)}(3))(4)] at −40 °C followed by low temperature NMR spectroscopy indicates a hydridoplumbylene intermediate [Cp(2)W(H)[double bond, length as m-dash]Pb(H)Ar*](+) (4b). Hydrido-tungstenotetrylenes of elements Ge (5c), Sn (5a) and Pb (5b) were also synthesized reacting the salt [Cp(2)W(H)Li](4) with organotetrylene halides. The metallogermylene [Cp(2)W(H)GeAr*] (5c) shows an isomerization via 1,2-H-migration to give the hydridogermylene [Cp(2)W[double bond, length as m-dash]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 [Cp(2)ZrH(2)](2) reacts with tin cation 1a to give the trinuclear hydridostannylene adduct 10 [({Cp(2)Zr}(2){μ-H})(μ-H)(2)μ-Sn(H)Ar*][Al(OC{CF(3)}(3))(4)]. Deprotonation of 10 was carried out using benzyl potassium to give neutral [({Cp(2)Zr}(2){μ-H})(μ-H)μ-Sn(H)Ar*] (11). 11 was also obtained from the reaction of low valent tin hydride [Ar*SnH](2) with two equivalents of [Cp(2)ZrH(2)](2). The trihydride Ar*SnH(3) reacts with half of an equivalent of [Cp(2)ZrH(2)](2) under evolution of hydrogen and formation of a dihydrostannyl complex 13 [Cp(2)Zr(μ-H)SnH(2)Ar*](2) and with further equivalents of Ar*SnH(3) to give bis(hydridostannylene) complex [Cp(2)Zr{Sn(H)Ar*}(2)].