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 ].